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SFUND RECORDS CTR 2109386 UNTIED STATES ENVIRONMENTAL PROTECTION AGENCY REGION IX 75 Hawthorne Street San Francisco, CA 94105 September 28, 2006 Samantha Roberts, Section Manager Remedial Programs Section Arizona Department of Environmental Quality 1110W. Washington St Phoenix, AZ 85007-2935 Re: Five-Year Review Concurrence, Motorola 52 nd Street Superfund Site, Operable Unit 1 (OU1) and Operable Unit 2 (OU2), Phoenix, AZ Dear Samantha: Thank you for the opportunity to concur on the Five-Year Review for the Motorola 52 nd Street Superfund Site (Site), dated September 25, 2006. The U.S. Environmental Protection Agency, Region 9 (EPA) has reviewed the Third Five-Year Review Report for OU1 and the Second Five-Year Review Report for OU2 for the Motorola 52 nd Street Superfund Site. This Five-Year Review is required pursuant to Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) §121 and the National Contingency Plan (NCP). Together, these regulations require that the remedial actions resulting in any hazardous substances, pollutants, or contaminants remaining at the site above levels that allow for unlimited use and unrestricted exposure be reviewed every five years to assure protection of human health and the environment. Since hazardous substances, pollutants, or contaminants are left on site above levels that allow for unlimited use and unrestricted exposure, this review is required for the Site. EPA has reviewed ADEQ's Five-Year Review and concurs with their recommendations. Although ADEQ has incorporated EPA's previous comments, the attached comments clarify several issues that were not completely addressed. Enclosed please also find the signature pages for the FYR concurrence. Thanks to you and your staff for working to get this done within our targeting deadline. EPA appreciates the opportunity to work with you on this report. If you have any questions, Page 1 of 2

FIVE YEAR REVIEW · Motorola 52nd Street Superfund Site, Five-Year Review Comments OU1 Five-Year Review ARARs, Section 7.2.1: We appreciate the State's preliminary analysis of potential

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SFUND RECORDS CTR

2109386

UNTIED STATES ENVIRONMENTAL PROTECTION AGENCYREGION IX

75 Hawthorne StreetSan Francisco, CA 94105

September 28, 2006

Samantha Roberts, Section ManagerRemedial Programs SectionArizona Department of Environmental Quality1110W. Washington StPhoenix, AZ 85007-2935

Re: Five-Year Review Concurrence, Motorola 52nd Street Superfund Site, Operable Unit 1(OU1) and Operable Unit 2 (OU2), Phoenix, AZ

Dear Samantha:

Thank you for the opportunity to concur on the Five-Year Review for the Motorola 52nd

Street Superfund Site (Site), dated September 25, 2006. The U.S. Environmental ProtectionAgency, Region 9 (EPA) has reviewed the Third Five-Year Review Report for OU1 and the SecondFive-Year Review Report for OU2 for the Motorola 52nd Street Superfund Site. This Five-YearReview is required pursuant to Comprehensive Environmental Response, Compensation andLiability Act (CERCLA) §121 and the National Contingency Plan (NCP). Together, theseregulations require that the remedial actions resulting in any hazardous substances, pollutants, orcontaminants remaining at the site above levels that allow for unlimited use and unrestrictedexposure be reviewed every five years to assure protection of human health and the environment.Since hazardous substances, pollutants, or contaminants are left on site above levels that allow forunlimited use and unrestricted exposure, this review is required for the Site.

EPA has reviewed ADEQ's Five-Year Review and concurs with their recommendations.Although ADEQ has incorporated EPA's previous comments, the attached comments clarifyseveral issues that were not completely addressed. Enclosed please also find the signature pagesfor the FYR concurrence.

Thanks to you and your staff for working to get this done within our targeting deadline.EPA appreciates the opportunity to work with you on this report. If you have any questions,

Page 1 of 2

please feel free to contact Nadia Hollan of my staff at 415-972-3187.

Sincerely,

Kathleen Johnson, Branch ChiefFederal Facilities and Site Cleanup BranchSuperfund Division

Enclosures

Cc: Kris Paschall, ADEQ

Page 2 of 2

Motorola 52nd Street Superfund Site, Five-Year Review Comments

OU1 Five-Year Review

ARARs, Section 7.2.1:

We appreciate the State's preliminary analysis of potential ARARs for the finalremedy. As is noted in the Five-Year Review, the OU1 ROD and LOD did not selectparticular ARARs for the interim remedy and the agencies have been depending on theregulatory framework set forth in the State's CO with the PRPs to ensure that statutorycleanup levels are met.

Because the ARARs process is discussed in the Five Year Review, the process bywhich ARARs are selected must be clarified. ARARs are cleanup standards,requirements or criteria, promulgated under state or federal law, that either specificallyaddress a contaminant, activity, or location at a CERCLA Site or a sufficiently similarsituation at the site that they are relevant and appropriate. TBCs, or To-Be-Considereds,are guidance that are not promulgated thus are not legally binding on their own but maybe used to determine the necessary level of cleanup for a particular site in the absence ofARARs.

There is a hierarchy to the selection of ARARs at a CERCLA site. In the firstinstance, federal environmental laws - along with state programs implementing federalenvironmental laws - are considered as ARARs. Where there are equivalent state lawsthat are more stringent than their federal counterparts, those more stringent requirementscan be the site ARARs. Finally, where there are no federal or state laws that areapplicable or.relevant and appropriate, federal and state guidance may be considered indetermination of risk-based cleanup levels for a site.

Applying this process for groundwater standards discussed in Section 7.2.1 of theFive Year Review would work as follows: EPA MCLs would be considered ARARs forgroundwater cleanup unless Arizona's AWQSs that apply to the same contaminants aremore stringent. And where there is no MCL or AWQS for a particular contaminant, theagencies may establish risk-based cleanup levels using as guidance the EPA Region IXPRGs and other non-promulgated guidance, such as Arizona's HBGLs.

The Morgan Well:

It is unclear from the Five-Year Review what the status is of the Morgan Well,located at 4626 East Granada Street, north of McDowell Road, that was installed in 1996northwest of the Freescale facility. The ATSDR Heath Assessments conducted in the1990s recommended increased frequency of well monitoring. The original Morgan Wellapparently went dry, but it had apparently not been used for domestic purposes with theexception of six months in the 1980s. But ATSDR's 1996 Site Review explains that theMorgan Well installed in 1996 is used for both irrigation and domestic purposes. In the

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most recent assessment, conducted by ADHS in April 2002, the well use was notverified, but assumed based on previous information it was used for swimming pool useand irrigation. This implies that the Morgan Well is not being used for domesticpurposes, such as drinking water. Two upgradient wells have had TCE concentrationssince 2001 of between 18 and 26 ppb TCE, well above the MCL of 5ppb. Therefore itshould be determined whether there is current domestic exposure at the Morgan Well. Ifit is determined that the Morgan Well is being used for domestic purposes, EPArecommends considering how to prevent such use. If the wellowner insists on utilizationof the Morgan well, TCE wellhead treatment could be offered. Alternatively, hookup toCity water supply could be offered.

Regardless of the use of the Morgan Well, the Five Year Review indicates thatthere has not been direct sampling of that well despite the recommendations in the 1990'sto increase its sampling frequency. Should ADEQ require assistance in gaining access tothe Morgan Well, EPA could provide both guidance and assistance in obtaining access.

Both OU1 and OU2 Five-Year Reviews

Institutional Controls:

In the discussion of follow-up actions from the previous OU1 Five-Year Reviewon page 28, there is no discussion of the potential for exposure to contaminatedgroundwater through exempt wells and the need for institutional controls at the Site.Although the ROD and LOD for OU1 and the ROD for OU2 did not identify particularinstitutional controls for the interim remedies, through the years, institutional controlshave been developed at this Site that have been successful in ensuring the protectivenessof the interim remedies and preventing exposure to Site contaminants. The State hasaddressed the concerns in part through conducting a well survey to identify exempt wells.Additionally, recommendation 13 in the OU1 Five Year Review is to provide notice topotential well owners through the Site fact sheet. EPA recommends that theseinstitutional controls become formalized either in the final remedy or through an interimdecision document.

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TTHHIIRRDD FFIIVVEE YYEEAARR RREEVVIIEEWW

OOPPEERRAABBLLEE UUNNIITT 11

MMOOTTOORROOLLAA 5522NNDD SSTTRREEEETT SSUUPPEERRFFUUNNDD SSIITTEE

PPHHOOEENNIIXX,, AARRIIZZOONNAA

SSEEPPTTEEMMBBEERR 2255,, 22000066

LFR Inc.

ACRONYMS AND ABBREVIATIONS

º F degrees Fahrenheit :g/kg micrograms per kilogram :g/l micrograms per liter A.A.C. Arizona Administrative Code ADEQ Arizona Department of Environmental Quality ADHS Arizona Department of Health Services ADWR Arizona Department of Water Resources ARAR Applicable or Relevant and Appropriate Requirements A.R.S. Arizona Revised Statutes AS air sparging ASRAC Arizona Superfund Response Action Contract AST aboveground storage tank ATP Acid Treatment Plant ATSDR Agency for Toxic Substance and Disease Registry AWQS Aquifer Water Quality Standard bgs below ground surface CAG Community Advisory Group CERCLA Comprehensive Environmental Response, Compensation and Liability Act CIP Community Involvement Plan cis-1,2-DCE cis-1,2-dichloroethylene or cis-1,2-dichloroethene CO Consent Order COC contaminant of concern COP City of Phoenix COS City of Scottsdale 1,2-DCB 1,2-dichlorobenzene 1,1-DCA 1,1-dichloroethane 1,1-DCE 1-dichloroethene DNAPL dense non-aqueous phase liquid DO dissolved oxygen EPA U.S. Environmental Protection Agency ERA Early Response Action Freescale Freescale Semiconductor, Inc. FS Feasibility Study FSP Field Sampling Plan ft/day feet per day ft/ft foot per foot GAC granular activated carbon gpd/ft2 gallons per day per square foot GPI Gutierrez-Palmenberg, Inc. GPL Groundwater Protection Limit gpm gallons per minuteHASP Health and Safety Plan IGWTP Integrated Groundwater Treatment Plant KOC organic carbon partition coefficient lbs/day pounds per day LFR LFR Inc. LOD Letter of Determination

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LFR Inc.

MCL maximum contaminant level MDL method detection limit MEK methyl ethyl ketone mg/kg milligrams per kilogram mg/l milligrams per liter ml milliliters Motorola Motorola Inc. MRL method reporting limit msl mean sea level MTBE methyl tertiary-butyl ether NAAQS National Ambient Air Quality Standards NCP National Contingency Plan NFA no further action NIOSH National Institute of Occupational Health and Safety NPL National Priority List OSHA Occupational Safety and Health Administration OSWER Office of Solid Waste and Emergency Response OU1 Operable Unit 1 OU2 Operable Unit 2 OU3 Operable Unit 3 PA Preliminary Assessment PCE tetrachloroethylene or tetrachloroethene PID photoionization detector ppb parts per billion ppm parts per million ppmv parts per million by volume PQGWWP Poor Quality Groundwater Withdrawal Permit PRP Potentially Responsible Party PSC Preliminary Site Characterization psi pounds per square inch PTP Pilot Treatment Plant PVC polyvinyl chloride QAPP Quality Assurance Project Plan QA/QC Quality Assurance/Quality Control RAO Remedial Action Objective RAP Remedial Action Plan RCRA Resource Conservation and Recovery Act redox oxidation-reduction RI Remedial Investigation ROD Record of DecisionRSRL Residential Soil Remediation Level SARA Superfund Amendments and Reauthorization Act of 1986 scfm standard cubic feet per minute SI Site Inspection SRL Soil Remediation Level SRP Salt River Project SVE soil vapor extraction SVETS Soil Vapor Extraction and Treatment System SVM soil vapor monitoring

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LFR Inc.

SWPL Southwest Parking Lot TAG Technical Assistance Grant TBC To Be Considered TCA 1,1,1-trichloroethane TCE trichloroethylene or trichloroethene TCLP Toxicity Characteristic Leaching Procedure TCZ Target Capture Zone TOC total organic carbon trans-1,2-DCE trans-1,2-dichloroethylene or trans-1,2-dichloroethene UST underground storage tank VOC volatile organic compound WQARF Water Quality Assurance Revolving Fund

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[This page intentionally left blank.]

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LFR Inc.

EXECUTIVE SUMMARY

The Third Five-Year Review for the Motorola 52nd Street Superfund Site, Operable Unit 1(OU1), located in Phoenix, Arizona was conducted by LFR Inc. (LFR) on behalf of ArizonaDepartment of Environmental Quality (ADEQ). The second Five-Year Review for OperableUnit 2 (OU2) is being conducted concurrently by ADEQ and LFR.

ADEQ is the lead agency for OU1 and is required to conduct this five-year review pursuant toComprehensive Environmental Response, Compensation and Liability Act (CERCLA) § 121 andthe National Contingency Plan (NCP). Together, these regulations require that the remedialactions resulting in any hazardous substances, pollutants, or contaminants remaining at the siteabove levels that allow for unlimited use and unrestricted exposure be reviewed every five yearsto assure protection of human health and the environment. Since hazardous substances,pollutants, or contaminants are left on site above levels that allow for unlimited use andunrestricted exposure, this review is required for OU1. The purpose of this five-year review is todetermine whether OU1 continues to meet remedial action objectives and is protective of humanhealth and the environment.

The five-year review consisted of the following activities: (1) review of relevant documents(Appendix A); (2) interviews with appropriate operations staff, state and federal agencies, localgovernment officials, and concerned community members; and (3) a site inspection.

The assessment identified several issues in the review of the OU1 treatment system. Based on aconservative interpretation of the data, using converging lines of evidence, it appears that thetarget capture zone (TCZ) in bedrock and to the north is questionable. ADEQ is also concernedthat the source area interim remedy is not significantly effective in reducing the levels ofcontaminants due to the dense non-aqueous phase liquid (DNAPL) in the fractured bedrock andthat high concentrations of trichloroethene (TCE) will continue in the source area wells for along period of time. In addition, groundwater concentrations in the shallow bedrock ports ofDM-125 and DM-601 appear to be increasing suggesting that the on-site groundwater extractionsystem may not be reducing or eliminating contaminant migration from the source area.

Several data gaps need to be filled in order to fully evaluate the OU1 capture effectiveness. Asthe OU1 Area conditions continue to change, additional groundwater elevation and quality dataare needed to adequately evaluate the OU1 interim remedy. The monitoring network needs to beevaluated and updated based on current site conditions and issues.

A review of applicable or relevant and appropriate requirements (ARARs) determined that thereare no newly promulgated standards; however, new ARARs and To Be Considereds (TBCs) arelikely to be determined for the final remedy.

A protectiveness determination of the OU1 interim remedy cannot be made at this time untilfurther information is obtained. The necessary follow-up actions and recommendations identifiedin this Report are needed to evaluate protectiveness. The actions will require the efforts ofFreescale and ADEQ to be completed. It is expected that these actions will take approximately 1year to complete, at which time a protectiveness determination will be made.

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___________________________________________________________________________________________LFR Inc.

Site Name: Motorola 52nd Street

EPA ID: AZD009004177

Region: 9 State: Arizona City/County: Phoenix/Maricopa

NPL Status: Final Deleted Other (specify)___________________________

Remediation Status: (choose all that apply): Under Construction Operating Complete

Multiple OUs? Yes No Construction Completion Date: Interim Remedy

Has site been put into reuse? Yes No (Site was never out of use.)

Reviewing Agency: EPA State Tribe Other___________________

Author Name: Robert Forsberg c/o LFR, Inc.

Author Title: Senior Hydrogeologist Author Affiliation: ADEQ Consultant

Review Period: September 2001 to July 2006

Date(s) of Site Inspection: June 8 and 9, 2006

Type of Review: Statutory Policy Post-SARA Pre-SARA NPL-Removal Only

Non-NPL Remedial Action Site NPL State/Tribe-Lead Regional Discretion

Review Number: First Second Third Other________________

Triggering Action:

Actual RA Onsite Construction at OU Actual RA Start at OU

Construction Completion Previous Five-Year Review Report

Other (Specify)_____________________________________________________________

Triggering Action Date: September 28, 2001

Due Date (five years after triggering action date): September 28, 2006

FIVE-YEAR REVIEW SUMMARY FORM

SITE IDENTIFICATION

REVIEW STATUS

SITE STATUS

xii

___________________________________________________________________________________________LFR Inc.

FIVE-YEAR REVIEW SUMMARY FORM

15. All PVC piping, valves, and other appurtenances showed signs of ultraviolet light weathering (eg., brittle appearance)..

16. The stainless steel steam pressure tanks were stress corroded and cracked.

17. Most steel appurtenances showed signs of rusting and/or corrosion.

DEFICIENCIES/ISSUES AND NOTED CONCERNS

10. Changes to the toxicity levels for certain contaminants have occurred since the last five-year review.

Health Assessment Issues

13. There is a potential for unregistered, private wells to exist in the OU1 Area.

xiii

11. New methodology is being developed for indoor air risk evaluation. Once the methodology is finalized or EPA and ADEQ can agree to the process for evaluating the pathway, an indoor air risk evaluation should be performed for the OU1 area.

12. The Baseline Risk Assessment and Health Assessments recommended to sample Mr. Morgan's well. Access may be an issue for sampling this well. A plan should be developed regarding this well.

1. Capture and containment can only be confirmed with an adequate monitor well network that provides both groundwater level data to demonstrate hydraulic capture and groundwater quality data to demonstrate overall reduction of mass within and outside the capture zone(s). Additional groundwater elevation and quality data are needed to adequately evaluate the OU1 system. The monitoring network needs to be evaluated and updated based on current site conditions and issues.

2. Based on a conservative interpretation of the data, using converging lines of evidence, it appears that capture of the TCZ in bedrock is uncertain. Additional bedrock monitor wells are needed to address the uncertainty of capture in bedrock both downgradient of the on-site system (DM-125, DM-601, and DM-606 areas) and the OCC system (between OCC and DM-118, DM-119, DM-120, DM-122, DM-123, DM-502, and DM503 area). Freescale has installed one multiport bedrock well; however, an increased monitor well network is needed to support the assessment of capture in bedrock.

5. Concentrations in extraction well DM-313 are currently very close to the MCL for TCE. Concentrations in this well have been increasing slightly over the last three years. If concentrations continue to increase and exceed the MCL, this well must be put back into operation.

3. Based on a conservative interpretation of the data, using converging lines of evidence, it appears the TCZ in the vicinity of EW-18 is questionable. Additional alluvial and bedrock monitor wells are needed in the vicinity of EW-18 to address the extent of contamination and evaluate capture of the TCZ.

4. Extraction primarily from the alluvial aquifer is credited for hydraulic capture at substantial depth in the bedrock aquifer. ADEQ is concerned that declining groundwater elevations at the site due to both regional decline and OU1 pumping will reduce the effectiveness of bedrock capture. As yield from the alluvial aquifer decreases, resulting changes in the predicted vertical capture needs to be addressed. The potential finite capacity of the system to capture bedrock contamination as the regional aquifer continues to decline represents a potential remedy problem.

14. The secondary containment system's protective coating showed signs of weathering (eg., cracking, peeling, lifting).

6. ADEQ is concerned that the source area interim remedy is not significantly effective in reducing the levels of contaminants due to the DNAPL in the fractured bedrock. ADEQ is concerned that high concentrations of TCE will continue in the source area wells for a long period of time.

7. Groundwater concentrations in the shallow bedrock ports of DM-125 and DM-601 appear to be increasing. These data indicate that the onsite groundwater extraction system may not be reducing or eliminating contaminant migration from the source area.

Operations and Maintenance Issues

Soil Issues

8. Confirmatory soil sampling should be conducted at the Courtyard to obtain closure. Soil sampling should be conducted once the Arizona Soil Rule and guidance has been finalized.

9. The CO required that an SVE system be installed at the ATP. No active soil remediation has been conducted in the ATP area to date. Soil sampling should be conducted at the ATP to obtain closure once the Arizona Soil Rule and guidance has been finalized.

Groundwater Issues

___________________________________________________________________________________________LFR Inc.

FIVE-YEAR REVIEW SUMMARY FORM

19. Air emissions and influent/effluent analytical data are an important tool for evaluating the effectiveness of the treatment system and should be reported in the annual Effectiveness Reports.

12. ADEQ and Freescale should develop a plan to collect groundwater samples from Mr. Morgan’s well and take further actions if necessary.

19. Freescale needs to include the air emission and groundwater influent/effluent analytical data in the annual Effectiveness Reports.

11. Freescale has previously prepared a work plan to address the vapor intrusion to indoor air pathway. Once the guidance for evaluating the vapor intrusion to indoor air pathway is finalized or EPA and ADEQ can agree to the process for evaluating the pathway, an indoor air risk evaluation should be conducted at the Site. The work plan should be updated to meet the final guidance requirements.

Groundwater Issues Corrective Actions

1, 2, and 3. A work plan should be prepared and submitted to ADEQ to address the OU1 data gaps identified in Section 8.1.1. The work plan should include a summary of the current conceptual site model, a review of the existing OU1 groundwater monitoring well network and other available data, identify the data gaps, and propose the work necessary to fill the data gaps.

17. Steel appurtenances that show signs of rusting and/or corrosion should be replaced.

7. Freescale should prepare a plan to evaluate the effectiveness of the source area treatment system.

General Issues Corrective Actions

14. The IGWTP secondary containment system's protective coating should be repaired.

CORRECTIVE ACTIONS AND RECOMMENDATIONS

Operations and Maintenance Issues Corrective Actions

Soil Issues Corrective Actions

8. Freescale should develop a work plan to evaluate the vadose zone at the Courtyard area. The work plan should include evaluation criteria for clean-up. ADEQ will provide Freescale with the evaluation criteria once the Soil Rule and guidance is finalized.9. A work plan should also be developed for obtaining closure at the ATP. The closure criteria will be established once the Soil Rule and guidance is finalized and should be included in the work plan.

18. ADEQ and Freescale should establish a list of COCs for the Site. Once the list has been established, Freescale should conduct a sampling round to evaluate the COC list for the RAOs for the final remedy.

18. The COCs should be identified for the final remedy.

xiv20. ADEQ will conduct a PRP search for upgradient sources and will evaluate whether these sources will impact the remedy.

15. The PVC piping, valves, and other appurtenances that show signs of weathering should be replaced.

16. The stainless steel steam pressure tanks should be replaced if they are brought back into use.

Health Assessment Issues Corrective Actions

10. A review of the toxicity values for COCs at the Site should be conducted before the final remedy is selected.

13. ADEQ will include a note in the next fact sheet requesting land owners to notify ADEQ of any private well.

4. A work plan should be prepared and submitted to ADEQ to address the bedrock hydraulic conductivity and extraction issues. The work plan should include the installation of a deep bedrock extraction and monitor wells such that a bedrock extraction pilot study may be completed to evaluate bedrock hydraulic conductivity. The results of the study should be incorporated into the feasibility study for the final remedy.

5. Freescale should prepare a plan to monitor the concentrations in DM-313. If these concentrations continue to increase and exceed the MCL, the well should be put back into operation.6. Freescale submitted a Groundwater Remedial Alternatives Analysis report in September 2005 followed by an Addendum to the Groundwater Remedial Alternatives Analysis report in December 2005 evaluating treatment technologies for DNAPL. The report is currently under review by ADEQ.

General Issues

20. Additional upgradient sources to groundwater contamination may exist.

___________________________________________________________________________________________LFR Inc.

FIVE-YEAR REVIEW SUMMARY FORM

xv

A protectiveness determination of the OU1 interim remedy cannot be made at this time until further information is obtained. The necessary follow-up actions and recommendations identified in this report are needed to evaluate protectiveness. The actions will require the efforts of Freescale and ADEQ to be completed. It is expected that these actions will take approximately 1 year to complete at which time a protectiveness determination will be made.

PROTECTIVENESS STATEMENT

LFR Inc.

1.0 INTRODUCTION

LFR Inc. (LFR) has prepared the Third Five-Year Review Report for Operable Unit 1(OU1) at the Motorola 52nd Street Superfund Site in Phoenix, Arizona on behalf of theArizona Department of Environmental Quality (ADEQ). The second Five-Year Reviewfor Operable Unit 2 is being conducted concurrently. The work was performed underArizona Superfund Response Action Contract (ASRAC) EV03-0073 and TaskAssignment 04-0071 dated September 29, 2005. The review period was from September30, 2001 through July 2006.

The purpose of the five year review is to determine whether OU1 meets remedial actionobjectives and is protective of human health and the environment. The methods, findings,and conclusions of the review are documented in this Report.

As the lead agency, ADEQ is required to conduct this five year review pursuant toComprehensive Environmental Response, Compensation and Liability Act (CERCLA) §121 and the National Contingency Plan (NCP). Together, these regulations require thatthe remedial actions resulting in any hazardous substances, pollutants, or contaminantsremaining at the site above levels that allow for unlimited use and unrestricted exposurebe reviewed every five years to assure protection of human health and the environment.Since hazardous substances, pollutants, or contaminants remain above levels that allowfor unlimited use and unrestricted exposure at OU1, this review is required for OU1.

This review was prepared according to Office of Solid Waste and Emergency Response(OSWER) Directive 9355.7-03B-P, Comprehensive Five-Year Review Guidance, June2001.

OU1 has been evaluated, monitored, and remediated since 1983 by Motorola Inc.(Motorola) and by Freescale Semiconductor, Inc. (Freescale) on behalf of Motorola. InDecember 2004, Motorola spun off its semiconductor sector to form a new independentcompany (Freescale) who has agreed to continue remedial actions at OU1 and OU2. Forthe purpose of continuity, Freescale will be used to refer to both Motorola and Freescalethroughout the Five-Year Review Report.

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LFR Inc.

2.0 SITE CHRONOLOGY

A chronology of OU1 events is included in Table 1.

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LFR Inc.

3.0 BACKGROUND INFORMATION

3.1 Site Location Information

The OU1 Area is part of the Motorola 52nd Street Superfund Site. The Motorola 52ndStreet Superfund Site consists of three operable units: OU1, OU2, and Operable Unit 3(OU3) (Figure 1). The Motorola 52nd Street Facility (formerly owned/operated byMotorola and currently owned/operated by ON Semiconductor) is located on thesouthwest corner of the intersection of 52nd Street and McDowell Road in the easternpart of Phoenix, Arizona. OU1 is defined by the contaminant plume to the north (PalmLane) and south (Roosevelt Street) and by the zone of hydraulic capture to the west (46thStreet). The property occupies approximately 90 acres and contains more than 20buildings on-site. Major geographic features include: the Papago Buttes about one mileeast of the Facility, the Salt River one mile south of the Facility, the Old Crosscut Canallocated along 46th Street, and the Grand Canal located through the area west of 40thStreet and Van Buren Street. The Phoenix Sky Harbor Airport is located approximately1.5 miles southwest of the Facility. Figure 2 is a site plan of the Facility that shows thelocations and names of the primary features and monitor wells. The following paragraphsprovide a brief summary of the site activities associated with OU1 at the Motorola 52ndStreet Superfund Site.

3.2 Land and Resource Use

The surrounding area is comprised of a mixture of residential, commercial, and industrialuses. The City of Phoenix provides drinking water to residents and does not currently usegroundwater within the OU1 Area as a source of water.

3.3 Site History and OU1 Information

The following sections provide a summary of the main site activities associated withOU1. The majority of the site information was obtained from the review of keydocuments associated with OU1. The list of key documents is included in Appendix A.Table 1 provides a brief summary of the chronological history of OU1.

3.3.1 Site Discovery

The Motorola 52nd Street Facility commenced manufacturing operations in 1956. InNovember of 1982, Freescale discovered a discrepancy in the inventory fortrichloroethane (TCA) in a 5,000 gallon underground storage tank (UST) located in theCourtyard Area (Figure 2). The UST was tested and determined to be leaking. TheArizona Department of Health Services (ADHS; ADHS was the precursor to ADEQ) wasnotified and a preliminary investigation of soil and groundwater contamination wasinitiated. Freescale discontinued the use of the tank and began to order solvents in55-gallon drums.

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LFR Inc.

3.3.2 Preliminary Investigation

In December 1983, a preliminary investigation report entitled “Preliminary Report –Chemical Leak Project,” (Preliminary Report) was submitted to ADEQ that verifiedvadose zone contamination sources at the site and a groundwater contamination plumemigrating west of the Facility. As part of the preliminary investigation, on-site andoff-site monitoring wells were installed and sampled from February 1983 throughNovember 1983. At many of these locations, multiple port wells (or Westbay Wells)were installed to allow sampling at different depths. In addition, private wellsdowngradient from the site were also surveyed and sampled.

The Preliminary Report identified twenty five combined possible sources ofcontamination in the Courtyard, Acid Treatment Plant (ATP), and Southwest Parking Lot(SWPL) areas. These sources included surface discharges, spills, tank and pipe leaks, anddischarges to leach fields and dry wells. The principle source of contamination wasdetermined to be the leaking TCA UST and a former dry well, both located in theCourtyard. This dry well was used for solvent disposal from 1963-1974 (prior toenvironmental regulations) and was abandoned in 1983. It was originally estimated thatapproximately 93,000 gallons of TCE was disposed to the dry well. The results ofsampling on-site and off-site monitoring wells and private wells showed that volatileorganic compounds (VOCs) were present at significant levels in the groundwater. TheReport identified the following chemicals of concern (COCs): TCE, TCA,tetrachloroethene (PCE), 1,1-dichloroethene (1,1-DCE), trans 1,2-dichloroethene(trans-1,2-DCE), and cis-1,2-dichloroethene (cis-1,2-DCE).

3.3.3 Remedial Investigation/Feasibility Study

As a result of the preliminary investigation, a Remedial Investigation/Feasibility Study(RI/FS) was initiated and a task force was formed to monitor the progress of the RI/FSthat included representatives of the U.S. Environmental Protection Agency (EPA),ADHS, the City of Phoenix (COP), the City of Scottsdale (COS), the Salt River Project(SRP), and Freescale. In addition, a Technical Subcommittee was also organized toprovide review and guidance for the implementation of the RI/FS. This subcommitteeincluded representatives of ADHS, Arizona Department of Water Resources (ADWR),EPA, SRP, Freescale, and Dames & Moore (Freescale’s Consultant).

The RI/FS was conducted from October 1984 to January 1987. The purpose of the RIwas to characterize potential sources of contamination, evaluate the physical environmentin which contamination occurred, and identify potential pathways of exposure. Thepurpose of the FS was to evaluate different remedial alternatives that would address theon-site contaminated soil and the on-site and off-site contaminated groundwater. Duringthe implementation of the RI/FS, several interim, or topical, draft reports were generated.Many of these reports included preliminary results from a particular aspect of theinvestigation. Other documents submitted included task specifications which describedhow a particular phase of the investigation would be completed.

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LFR Inc.

The major RI activities performed during the period from October 1984 to January 1987were as follows:

• Part of the RI activities involved installation of monitoring wells to furthercharacterize horizontal and vertical hydrogeologic and water quality conditionson and off-site. Well installation activities commenced in November 1984 andcontinued through August 1986. The locations of these wells are shown in Figure2.

• In November 1984 and February/March 1985, soil-gas investigations wereconducted at the Site.

• Source verification investigations (Stage 1) were performed from October 1985 toFebruary 1986. The distribution of the 18 sources was comprised of 3 sources inthe SWPL area, 3 sources in the ATP area, and 12 sources in the Courtyard area.

• In September and October 1986, a well survey was conducted to identify existingmonitoring wells, public supply wells, and private wells in an area downgradientfrom the Site. The area surveyed was bounded by Oak Street to the north,Washington Street to the south, 52nd Street to the east, and 24th Street to thewest.

The chronology of the major FS activities performed during the period of October 1984to January 1987 are as follows:

• During May 1986, Freescale voluntarily initiated an on-site groundwatertreatment program. Two groundwater extraction wells, DM-301 and DM-302,were installed in the Courtyard area (Figure 4) to supply contaminatedgroundwater to the Pilot Treatment Plant (PTP). DM-301 was drilled next toexisting well MP-3. MP-3 exhibited the highest concentrations of TCE, TCA, andother VOCs and contained dense nonaqueous phase liquid (DNAPL). WellDM-302 was installed in the Courtyard near the dry well, the major source of theVOC contamination.

• On August 8, 1986, the results of the preliminary screening of remedial actiontechnologies and/or alternatives were submitted to ADEQ as a draft report. Thepreliminary screening process identified five technologies to be screened fordetailed evaluation. These technologies included: (1) groundwater extraction andbarriers; (2) water and soil treatment; (3) in situ processes; (4) waste containmentand removal; and (5) water supply and drainage control. The preliminaryscreening of technologies was separated into “on-site source control” and “off-sitemanagement of migration”. The following four alternatives (3 on-site and 1off-site) were advanced to the detailed final alternatives evaluation:

- on-site Source Control Alternatives: groundwater extraction in thealluvium and treatment; groundwater extraction in bedrock and treatment;and in situ soil vapor extraction; and

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- off-site Management of Migration: groundwater extraction from thealluvium and bedrock and treatment of the water.

Other FS activities performed after the screening process included: a detailed costestimate of the design and installation of each alternative; conduct a risk assessment toevaluate exposure pathways and to collect toxicological data on contaminants; a detailedcapital and operations and maintenance cost estimate; and model simulations of remedialalternatives.

• On September 4, 1986, a work plan to implement the groundwater PTP wasissued.

• The PTP was operated from September 15, 1986 until the time the IntegratedGroundwater Treatment Plant (IGWTP) was put online (See Section 3.3.6 and3.3.8).

3.3.4 Remedial Investigation Report

In June 1987, the results of the RI performed at OU1 were presented in a draft report andissued for public review and comment. The purpose of the RI Report is to summarize theresults of source characterization and site investigation. The following conclusionsreached in the RI Report were based on previous data collected during the preliminaryinvestigation, field data collected during the RI activity and groundwater flow andtransport modeling that was performed during the RI.

• The results of the source verification investigation showed contaminantconcentrations at three source locations (Courtyard, ATP, and SWPL). At theselocations, organic contaminants were found in both soil and groundwater. The drywell, located in the Courtyard, had the highest concentration of VOCs in soil andgroundwater. The high levels of VOC concentrations in the saturated andunsaturated zones at the dry well and the TCA UST indicated the presence ofDNAPL.

• Results of the geological studies from the RI, and more recent investigations,identified two distinct geological units. These include: (1) the unconsolidatedalluvium, composed of loose sediment (i.e. - sand, clay, silt, cobbles, andboulders) and (2) the bedrock, consisting of Precambrian metarhyolite and graniteas well as Tertiary volcanics and consolidated sediments. It has beendemonstrated that groundwater and contaminants move between the alluvium andthe bedrock. The shallow alluvium is unsaturated, and therefore, groundwateroccurs only in the deeper alluvium, identified as basin fill. The alluvium varies inthickness from less than 20 feet at the Facility to over 150 feet at 40th Street. Thealluvium generally becomes thicker to the west.

• Groundwater beneath the Facility lies at depths ranging from 20 to 25 feet belowground surface (bgs). Groundwater depths off-site ranged from 20 to 50 feet bgs.The saturated thickness of the alluvium varies from less than 10 feet at the

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Facility to more than 100 feet off-site. The hydraulic characteristics of thealluvium and bedrock indicate that the hydraulic properties of these units vary,with the greatest change at the contact between the alluvium and bedrock. In thealluvium, hydraulic conductivity varies from about 2 feet per day (ft/day) to morethan 60 (ft/day). The thickest alluvium has the highest hydraulic conductivity.The alluvial hydraulic conductivity in the vertical direction is believed to be aboutone-tenth as large as the hydraulic conductivity in the horizontal direction.

• Bedrock underlying the basin fill has undergone several deformational eventsresulting in faulting, fracturing, rotation, and vertical and horizontal displacement.Two dominant fracture, fault, and lineament trends may be observed: anorthwest-southeast trend and a northeast-southwest trend. Hydraulicconductivity in the bedrock is strongly influenced by the presence and frequencyof fractures. Measurements of hydraulic conductivity in bedrock vary from 0.001to 2 ft/day. The alignment of an apparent erosional channel in the Courtyardparallels a probable bedrock fault.

• Soil, groundwater, and bedrock contamination have been documented on-site.TCE is the major VOC contaminant. TCA contamination is more recent and is notas extensive as TCE contamination. Groundwater contamination extends to thewest and then west-southwest of the Facility and consists primarily of VOCs. TheDNAPL is thought to exist primarily within the fractures of the bedrock as afree-phase DNAPL. Since the DNAPL undergoes only limited degradation, itpersists for long periods of time while slowly dissolving into the groundwater.The DNAPL is essentially immobile and recovery using pumping wells isextremely slow.

• Inorganic constituents were detected in groundwater samples collected during theinvestigation. The concentration of major inorganic constituents was about twiceas high in the alluvium than in bedrock. Two zones of inorganic contaminationwere determined: (1) the Courtyard area where total dissolved solids (TDS)concentrations ranged from 1,000 parts per million (ppm) to 4,000 ppm and (2)SWPL where TDS concentrations ranged 2,000 ppm to 7,000 ppm. In addition,fluoride, nitrate, and heavy metals exceeded drinking water standards in on-siteand off-site wells.

• A groundwater flow and contaminant transport model was used to predict existingand potential contaminant migration. These results were sufficient to allow theexamination of remedial action alternatives in the FS Report. The nature andextent of contamination was defined and sufficient data existed to evaluate therelative benefits of the cleanup to protect public health, welfare and theenvironment.

3.3.5 Feasibility Study Report

In June 1987, the results of the FS performed at OU1 were presented in a draft report andreleased for public review and comment. The purpose of the Feasibility Study was

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to: (1) establish remedial objectives; (2) identify alternative remedial approaches; and (3)to evaluate those remedial alternatives.

The OU1 remedial objectives that were identified in the FS were: (1) to protect humanhealth and the environment; (2) reduce contamination levels in groundwater; (3) providecontainment of contaminated groundwater at the Old Cross Cut Canal; (4) expediterecovery of contaminated groundwater; (5) assure beneficial use of contaminatedgroundwater that is extracted and treated; and (6) incorporate permanent solutions andinnovative technologies in the cleanup process to the extent possible.

The FS Report presented the following eight remedial action alternatives: (A)Groundwater Recovery from Alluvium – Courtyard; (B) Groundwater Recovery fromAlluvium and Bedrock – Courtyard; (C) Groundwater Migration Control – Courtyard andOld Crosscut Canal; (D) Groundwater Migration Control – Courtyard and Downgradientin the Alluvium; (E) Downgradient Alluvial Pumping plus Alluvial and BedrockPumping On-Site; (F) Source Removal/Containment; (G) Extensive DowngradientPumping of Alluvium; and (H) Extensive Downgradient Pumping of Alluvium plusRecovery from Bedrock between 50th Street and the Old Crosscut Canal.

During the evaluation, each alternative was reviewed with the following criteria: (1)implementability; (2) cost; (3) technical feasibility; (4) time to accomplish the cleanup;(5) protective of human health and the environment; (6) satisfy applicable or relevant andappropriate requirements (ARARs) and/or remedial objectives; and (7) environmentalimpacts.

The result of this evaluation identified Plan C as the most feasible alternative thataddressed all of the evaluation criteria. Plan C had the following advantages over theother alternatives evaluated in the study:

• effectively reduces the area with VOC contamination in excess of health-basedcriteria within 10 years of operation;

• provides a hydraulic barrier against further migration of VOC contamination fromthe area east of the Old Crosscut Canal;

• provides containment of inorganic contamination west of the SWPL area;

• is cost-effective relative to plans with more extensive pumping areas;

• is essentially equal in present worth and unit removal costs with Plan B, whilereducing off-site contamination better than Plan B;

• decreases the area requiring non-drinking water use restrictions; and

• among the plans which include off-site construction, Plan C minimizes off-siteimpacts and permit requirements.

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The FS Report concluded that Plan C satisfied the evaluation criteria mandated byCERCLA and the Superfund Amendments and Reauthorization Act of 1986 (SARA).Additionally, Plan C would eventually achieve the remedial objectives for groundwatereast of the Old Crosscut Canal. The FS Report further concluded that Plan C meets theSARA alternative technology requirement by employing soil-gas extraction as asupplement to ground-water pumping and treatment in the Courtyard, and as areplacement to pumping and treating groundwater in the areas of the ATP and SWPLareas. Due to the deep migration and high concentrations of VOCs in the Courtyardgroundwater, soil-gas extraction could not replace pumping and treatment. In summary,Plan C was determined to be technically feasible, reliable, efficient, cost effective, andwill protect the public health and the environment.

3.3.6 Remedial Action Plan

A draft Remedial Action Plan (RAP) was prepared by Freescale and submitted to ADEQon June 24, 1988. The purpose of the RAP was to propose a remedy from the remedialalternatives evaluated in the FS and allow the public to review and comment on theselected plan. Alternative C was proposed as an operable unit, meaning a partial orinterim remedial measure. The operable unit would serve as an interim remedy intendedto reduce contaminant concentrations and provide capture of contaminated groundwateruntil a final remedy is selected. Consequently, OU1 was intended to be the first stage ofan expanded program which would involve innovative technologies, such as in situbiodegradation of VOCs.

The RAP provided a detailed description of Plan C which consisted of on-site and off-siteextraction wells, an 810 gallons per minute (gpm) groundwater treatment plant locatedon-site, and on-site soil gas treatment. The treatment plant would include air stripping fororganics removal with air emissions control. Treated effluent would be piped for use atlocations in the Freescale plant to replace water supplied by the City of Phoenix.

The RAP outlined a program to evaluate the effectiveness of OU1 which included: (1)regular sampling and testing of extraction wells, the treatment plant, and soil-gasextraction systems; (2) periodic groundwater quality and soil gas monitoring; (3) periodicperformance assessments that would focus on actual versus predicted achievement ofcleanup levels; (4) testing the assumptions made regarding the DNAPL in the Courtyard;(5) the length of time to achieve cleanup objectives would be evaluated on a regularbasis; (6) semiannual or yearly effectiveness reports, and (7) as required by CERCLA, acomplete reassessment of the operable unit every 5 years.

The well survey conducted during the RI concluded that there were no known wells usedfor drinking water purposes. Therefore, the implementation of the selected remedy wouldprotect human health and the environment from all known current uses of thecontaminated groundwater. The only potential use of groundwater identified in the OU1area was for lawn irrigation and to fill swimming pools.

Freescale proposed to initiate implementation of Plan C as soon as possible. The remedialmeasures were begun in 1988 with the expansion of the PTP.

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3.3.7 Letter of Determination, Record of Decision, and Consent Order

In September 1988, ADEQ issued a Letter of Determination (LOD) and the EPA issued aRecord of Decision (ROD) for OU1. The LOD and ROD provided ADEQ’s and EPA’sapproval of the RAP and outlined precisely what remedies are associated with OU1. TheLOD and ROD also provided an explanation of how these remedies would be protectiveof human health and the environment. The LOD also provided a responsiveness summaryof comments received during the public comment period of the OU1 RAP.

On June 20, 1989, Freescale signed a Consent Order (CO) with ADEQ agreeing toimplement a groundwater and soil remedy for OU1. The purpose of the CO is to serve thepublic interest by protecting public health, welfare, and the environment from releases ofhazardous substances at the Site. Freescale was identified as a responsible party and, asrequired by the LOD/ROD, ordered to contain and control the migration and reduce thelevel of contaminants in the groundwater. The work was to be conducted as described inthe CO. On July 26, 1989, the Motorola 52nd Street CO was lodged with the ArizonaSuperior Court.

The CO was issued to establish an agreement between Freescale and ADEQ to: (1)design, construct, implement, and maintain a groundwater extraction, conveyance, andtreatment system; and (2) to design, construct, and operate three SVE systems on-site.The CO acknowledged that the OU1 LOD/ROD does not constitute the final remedy forthe Site, and no clean up level for the contaminated aquifer was established. The finalremedy will be determined after completion of a Final RI/FS and ROD. However, inoperating OU1, Freescale is still required to comply with Arizona treatment standards forall contaminants attributable to the Motorola 52nd Street Facility.

The following outlines the requirements of the CO that are required to be met byFreescale:

• OU1 shall maintain a zone of capture to contain the migration of contaminationeast of the Old Cross Cut Canal;

• OU1 shall reduce the levels of contamination in groundwater, including bedrock;

• all water from the groundwater extraction and treatment system will bebeneficially used at the Motorola 52nd Street Facility consistent with theGroundwater Code, including applicable area management plans;

• the treatment plant discharges shall meet federal, state, and local standards fortreatment plant discharge levels;

• the total concentration of VOC’s shall not exceed 100 parts per billion (ppb) indischarges of treated groundwater;

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• Total Toxic Organic (TTO) concentrations in the wastewater discharged from theMotorola 52nd Street Facility shall not exceed the average value measured (186ppb) during the 3 years prior to the entry of this CO;

• should the 3-year average of TTO’s be exceeded for 3 consecutive months, thetotal concentration of VOC’s in the treated groundwater must not exceed 50 ppbof VOC’s, of which there must be less than 5 ppb of TCE.

• an SVE system shall be designed to extract and treat soil gas throughout thethickness of the unsaturated zone until VOC concentrations are reduced to levelsthat stabilize at minimal concentrations of recovery, or are so low as to renderextraction uneconomical as agreed to by ADEQ.

As a result of information provided in the RI/FS, ROD, LOD, and CO, the Site wasplaced on the EPA CERCLA National Priorities List (NPL) in October 1989.

3.3.8 Integrated Groundwater Treatment Plant

The groundwater PTP within the Courtyard area was in operation until July 1992 whenthe permanent IGWTP became operational (Figure 2).

• On March 12, 1991, the 100% completion design drawings for the off-sitegroundwater extraction and conveyance system were submitted to ADEQ.

• On May 6, 1992, a Baseline Report prior to the startup of the IGWTP wassubmitted to ADEQ. This Baseline Report was used to compare against thereports for subsequent years in order to evaluate the effectiveness of OU1.

• In July 1992, the IGWTP commenced operations.

Operation of the IGWTP was temporarily suspended in June 1993 due to a vinyl chlorideair emission problem. After a six-month shutdown to fix the problem, the entireextraction system was put back into continuous operation on December 28, 1993. Theeffect of the shutdown was evaluated in the 1993 OU1 Effectiveness Report. Thetreatment system has been operated on a relatively continuous basis since December1993. In December 2001, the treatment system was shut down for an ADEQ-approvedsystem evaluation. The system was restarted in February 2002. The effect of thisshutdown was evaluated in the 2001 OU1 Effectiveness Report. The system wasshutdown again on April 1, 2003 following the discovery of cracks in the vapor phaseactivated carbon vessels. A new “roll-off” type of carbon unit was installed and thetreatment system returned to operation on August 4, 2003. The effect of this shutdownwas evaluated in the 2003 OU1 Effectiveness Report.

In August 2000, the updated Operation and Maintenance (O&M) Manual for the IGWTPwas submitted to ADEQ. The O&M manual consisted of basic system design criteria,operation and maintenance requirements of major system components, and monitoringand reporting requirements. The OU1 system is controlled by computer through a main

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control panel located at the IGWTP and monitored by operational personnel. The manualalso established site specific health and safety requirements necessary for safe andefficient operation of the groundwater treatment system.

The on-site IGWTP Management Team is responsible for the safe operation andcompliance with all safety, environmental, governmental, regulatory, and Freescalerequirements. However, since the IGWTP is located on the ON Semiconductor campus,the Management Team must also coordinate certain activities and communications withpersonnel at ON Semiconductor.

The O&M Manual is intended to be used in conjunction with the OU1 Health andSafety/Emergency Response Plan (HASP). The OU1 HASP is revised occasionally toreflect changes in equipment, operations, and procedures.

3.3.9 Poor Quality Groundwater Withdrawal Permit

On May 8, 1991, ADWR issued Poor Quality Groundwater Withdraw Permit(PQGWWP) #59-530577, for the OU1 groundwater extraction program. The permitrequired quarterly monitoring and reporting for both extraction and monitoring wells.The purpose of the permit was to: (1) provide information about the quality ofgroundwater and determine when the groundwater ceases to be classified as “poorquality”, and (2) ensure that groundwater withdrawal is consistent with the 1991 PhoenixActive Management Area Second Management Plan. The definition of “poor quality” isdetermined by comparing groundwater data to EPA maximum contaminant levels(MCLs), or ADEQ’s aquifer water quality standards (AWQSs), for the contaminants ofconcern. If results of the collected groundwater data exceed the MCL/AWQS for one ormore contaminants, the groundwater remains classified as “poor quality”.

Beginning in October 1991, after appropriate monitoring plans were developed, quarterlygroundwater monitoring of the OU1 wells in accordance with the PQGWWP wasinitiated. The first PQGWWP Progress Report was submitted on January 28, 1992.Quarterly PQGWWP monitoring and quarterly/annual reporting activities continuedthrough the end of 1997. On January 5, 1998, Freescale submitted a Request forModification to the PQGWWP to eliminate chloroform, 1,2-DCE, and carbontetrachloride from the key parameters list, and to reduce the sampling frequency tosemiannually. This modification request was approved by ADWR. An AmendedPQGWWP is included in Appendix B.

3.3.10 Groundwater Monitoring and Progress Reporting

On May 12, 1987, a task specification document was submitted to ADEQ to establish along-term groundwater monitoring plan for the Site. This plan was updated by Freescaleand approved by ADEQ on January 26, 1998. Under this monitoring plan, wellsassociated with OU1 would be sampled on a semiannual or annual basis with water levelsmeasured quarterly. The locations of the OU1 wells are shown in Figure 2.

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In addition to the semiannual Groundwater Monitoring/PQGWWP Report, Freescale alsosubmits an annual Effectiveness Report. The purpose of this report is to provide anassessment of the overall effectiveness of OU1 with respect to hydraulic containment ofcontaminated groundwater. Freescale concluded in each of their yearly evaluations thatOU1 has maintained a capture zone adequate to contain the entire width and depth of theTCE contaminant plume (Appendix C). The total gallons pumped from OU1, frompre-1992 through 2005, were estimated to be 2.52 billion gallons. The total DNAPLremoved at MP-03-D, from 1994 through 2005, was estimated to be 166 pounds. Thetotal VOCs removed from the groundwater in OU1, from 1992 through 2005, wasestimated to be 17,265 pounds. The reports further concluded that the overall trend ofTCE concentrations in the groundwater remained consistent with the trends observed inprevious years; initially high TCE concentrations were steadily decreasing. Additionally,the reports concluded that the reduction in TCE concentrations in the alluvium at anddowngradient from the Old Crosscut Canal indicates that continuous pumping at OU1has had a beneficial effect on the water quality in the alluvium. This was apparent whencomparing the 1992 baseline TCE concentration maps to the September 2001, 2002,2003, 2004, and 2005 TCE concentration maps (Appendix C). Freescale suggests that theincreasing concentrations of TCE around the alluvium/bedrock interface indicates thatTCE is slowly moving upward along fractures in the bedrock, increasing theconcentration in shallow bedrock monitoring ports while migrating toward the extractionwells.

The conclusions presented in the OU1 Effectiveness Report, 2005 Operations datedMarch 2006 indicated that OU1 extraction systems maintained a capture zone adequate tocontain the entire width and depth of the plume. Freescale indicated that the extent ofvertical capture was at least 400 feet in depth. On-site extraction wells maintain capturein the alluvium and bedrock in the Courtyard area to a depth of approximately 150 to 200feet bgs. Further evaluation of these findings is presented in Sections 7 and 8.

In 1999, Freescale submitted the Characterization of Inorganic Constituents inGroundwater, 52nd Street Superfund Site Report. The Report described the nature andextent of inorganic constituents in groundwater at the 52nd Street Superfund Site basedon data collected between 1983 and 1996. Freescale identified arsenic, fluoride, andnitrate as the only inorganic constituents warranting further evaluation. Followinganalysis, Freescale concluded that the elevated concentrations of arsenic, fluoride, andnitrate were likely attributable to historical land use and/or naturally occurring alluvialsources.

3.3.11 Health Assessment Studies

On May 2, 1988, the Agency for Toxic Substance and Disease Registry (ATSDR)submitted the results of a health assessment for contaminants associated with OU1. Thehealth assessment was performed in accordance with SARA. The Health Assessmentreport surmised that: (1) the groundwater, soil, and soil gas at the Motorola 52nd StreetFacility is contaminated with high concentrations of VOCs; (2) the COCs found ingroundwater, soil, and soil gas at the site included TCE; 1,1-DCE; 1,1-DCA; and PCE;

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(3) the contaminated groundwater had migrated off-site to the west; (4) lowconcentrations of the site-related VOCs, specifically 1,1,1-TCA, TCE, and PCE, weredetected in some off-site wells that were currently in use; (5) off-site groundwater wasknown to be used for the irrigation of crops and lawns and filling swimming pools; (6)water from some on-site and off-site wells contained elevated concentrations of inorganicchemicals such as arsenic, cadmium, chromium, lead, and nitrate; and (7) the availableinformation did not indicate whether these inorganics were naturally occurring in thewater or whether their presence was related to industrial activities. In addition, the healthassessment was conducted based upon the assumption that groundwater within the Sitearea would not be used for potable purposes. Environmental pathways for contaminantsfrom the site included groundwater, soil, air, and food. Low concentrations ofcontaminants in surface water indicated that surface water and sediments were notpathways of concern for this Site.

The following exposure routes were evaluated: (1) ingestion or use of contaminatedgroundwater or contaminated agricultural products; (2) dermal contact of groundwatercontaminants and ingestion of water during swimming; (3) inhalation of VOCcontaminants and fugitive dusts; and (4) consumption of plants or animals which mayhave bioaccumulated groundwater contaminants.

The Health Assessment Report concluded that under current conditions (at the time of theHealth Assessment) the Site is unlikely to pose any threats to human health. Althoughon-site and off-site groundwater is contaminated, contaminant levels at the points ofgroundwater extraction were below the levels of concern. However, the Report notes thatfuture migration of groundwater contaminants may increase the level of contaminants atpoints of groundwater extraction and may render the groundwater unsuitable for evennon-potable uses. The Report also concludes that soil and soil-gas contaminants shouldnot pose a threat to human health.

The Health Assessment Report provided the following recommendations in order toensure continued protection of human health: (1) continue to monitor off-sitegroundwater contamination to track the movement of the contaminant plume and definethe extent to which the Site has impacted groundwater quality; (2) continue to monitoroff-site wells in the impacted areas that are being used for irrigation or residential use; (3)workers conducting remedial activities should use adequate personal protectiveequipment which meets Occupational Safety and Health Administration (OSHA)standards and appropriate National Institute for Occupational Safety and Health (NIOSH)recommendations; (4) dust generated during remedial activities should be optimallycontrolled; (5) during remedial activities, real-time work site periphery air monitoringshould be done in addition to on-site air monitoring; and (6) ambient air at the peripheryof the Site should not exceed the National Ambient Air Quality Standards (NAAQS) orthe NIOSH recommendations.

As a follow-up to the 1988 Health Assessment, ATSDR conducted a Site Review andUpdate in 1993 and 1996. Additionally, ADHS completed a Baseline Risk Assessment inNovember 1992. These assessments included both OU1 and OU2, however, for thepurposes of this five year review, only the OU1 issues will be discussed.

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The 1992, 1993, and 1996 assessments discussed two private wells within the OU1 area:Well 4626G (Morgan well) and the Turnage well. The Morgan well is located northwestof the Freescale facility at 4626 East Granada Street, just north of McDowell Road. It is aprivate water supply well registered for domestic use and has been primarily used forresidential swimming pool water and for grounds irrigation. The well was also used forindoor domestic purposes for a period of about six months in the late 1980's. TheBaseline Risk Assessment provided a summary of the analytical data from the Morganwell collected between 1987 and 1992. During this period, boron, fluoride, and lead weredetermined to exceed the MCLs. Four organic compounds were found in the samples butnone exceeded the MCLs. The assessments recommended an increase in the frequency ofmonitoring the Morgan well.

The Turnage well is located at 1502 North 46th Street, just south of McDowell Road.This well was used as a domestic water source for about 20 years, from 1948 to 1969 or1970. The well was sampled by ADEQ for VOCs during the period from 1984 to 1986.Ranges in reported concentrations were: TCE at 1,300 to 8,100 ppb; PCE at 14.2 to 60ppb; 1,2-dichlorobenzene (1,2-DCB) at < 2 to 45 ppb; 1,2-trans DCE at 3.1 to 98.7 ppb;and methylene chloride at < 0.5 to 6,350 ppb. Sampling by ADEQ was discontinued in1986 when Freescale installed monitor well DM-106 in close proximity to the Turnagewell. In 1986, a locked steel housing was installed to protect the well and prevent its use.Access to the well was controlled by Freescale since installing the lock. The well wasabandoned on January 25, 2005. The time at which the well became contaminated is notknown and cannot be established. It is not possible to estimate past risk from domesticuse of the well water for a 20 year period ending approximately in 1970. The risk canonly be calculated for those periods of time that analytical data was collected. Therefore,since data was not collected until approximately 14 years after the well was removedfrom service, and there is no way to predict the VOC concentration levels from 1948 to1970, it is not possible to estimate past risk. ADHS did not use the Turnage well in thequantitative risk assessment due to the lack of data and the fact that the well was notcurrently in use.

A list of recommendations that were made in the ATSDR 1993 Site Review and Updatewere reassessed in the 1996 Site Review and Update Report to ensure that they had beenaddressed. The 1996 Site Review and Update identified several issues specific to OU1that still had not been addressed including (1) institutional controls were to remain inplace, however, none of the agencies contacted were aware of any controls and (2) thefrequency of monitoring the Morgan well had not been increased as recommended.ADEQ reported that it had not been sampled for years because Mr. Morgan did not wanthis well sampled any longer. Also, ATSDR reported that Mr. Morgan installed a newwell in February 1996 because his original well went dry. Mr. Morgan’s new well isregistered with ADWR and is used for irrigation and domestic purposes.

In the early 1990s, ADEQ installed a monitor well, EW-18, directly east (upgradient) ofthe Morgan well. EW-18 was initially sampled in 1992 and had a TCE concentration of23 ppb. EW-18 is sampled semiannually and TCE concentrations in the last five yearshave been between 18 ppb and 26 ppb. Since 2001, TCE concentrations have beenrelatively consistent each year.

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The 1992 Baseline Risk Assessment includes a map which provides the locations of themonitor wells, domestic use wells, and public irrigation wells that are located in the OU1and OU2 areas. A well located at 1050 North 46th Street (south of McDowell Road),referred to as the Willis well, is shown to be “closed”. This well was abandoned in 1990for construction of the Loop 202 and Hohokam freeways. There were no discussionsregarding this well in the 1988, 1992, 1993, or 1996 health assessments.

ADEQ assigned a special task to ADHS to conduct an exposure assessment focusing oncontaminated soil gas. Two exposure scenarios were used: indoor residential and outdoorresidential. It was assumed that soil gas diffused from the soil to the ambient air and intoresidential structures through crawl spaces or via cracks in cement slabs. In April 1992,ADHS issued their report, Addendum to Motorola 52nd Street Baseline RiskAssessment; Soil Gas Sampling, which concluded that residential populations do notappear to be at risk of negative health effects from exposures to soil gases in the areawest of the Motorola 52nd Street Facility. Concentrations of 1,1-DCE are high enough tosuggest that further study of potential indoor exposures may be warranted. TheNovember 1992 Baseline Risk Assessment does not address this issue nor do the ATSDRSite Reviews and Updates.

In April 2002, ADHS conducted a health assessment of the Motorola 52nd StreetSuperfund Site area to identify any current groundwater use that might result in humanexposure to site contaminants. The Report updated the 1992 well use inventory for OU1and OU2 and provided an evaluation of potential groundwater exposure pathways inOU3. The Report concluded that for those wells whose status was verified, no exposureto contaminated groundwater was found; therefore, those wells pose no public healthhazard. However, unregistered private wells might exist within the Motorola 52nd StreetSuperfund Site.

Freescale submitted the Potential Indoor Air Vapor Intrusion Risks for Motorola 52ndStreet Superfund Site Operable Unit 1 memorandum to ADEQ on December 6, 2005(Sciences International, 2005). The memorandum evaluated the risks from potentialvapor intrusion into residences within the OU1 Area using soil gas data collected in1995. Shallow soil gas samples were collected from a depth of approximately five feetbgs from twenty three locations. Screening levels were generally based on EPA’spublished cancer and non-cancer potency factors. If no EPA factors were available,California EPA inhalation potency factors were used. The results show low total potentialrisk levels that are within the presumptively acceptable risk range of 10-6 (or lower) to10-4. Most of the results were below the 10-6 risk level. TCE and PCE were the onlyCOCs detected at concentrations above soil gas risk-based screening levelconcentrations. Only 2 of the 23 locations show estimated values above the 10-5 risklevel. Freescale’s evaluation is currently being reviewed by ADEQ and EPA and nodetermination of risk has been determined.

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3.3.12 Groundwater Modeling of Capture in Alluvium and Bedrock

The April 1995 OU1 Effectiveness Report for 1994 provided a discussion of captureanalysis. The analysis was used to support deep bedrock capture by the OU1 system. Thecapture analysis focuses on interpretation of hydraulic head data to determine hydrauliccapture. The main sections of the document are: discussions of the alluvial aquifer andfractured bedrock systems, a numeric model simulation of OU1, and analysis ofhydraulic head data and hydraulic capture. Horizontal and vertical gradient (both beforeand during pumping) data were used in the capture analysis. A three-dimensionalTARGET 3DS finite-difference code was used to construct a model to simulate the OU1system. The model was designed to simulate the two layer system (alluvium andbedrock) at the Site. Two model simulations were included: one with isotropic bedrockpermeability, another with anisotropic bedrock permeability. According to the captureanalysis, the model is not intended to account for the full detail of the Site, but toimprove understanding of capture in the alluvial aquifer and fractured bedrock systems atOU1.

Freescale submitted an OU1 Evaluation Model Report dated September 28, 2005. Thepurpose of the Report was to (1) simulate groundwater flow in the vicinity of the 52ndStreet Facility and calibrate the model to conditions from 1992 through 2003 and (2)provide a tool to evaluate future changes in the operations of the OU1 system. The modelwas constructed based on field data collected over many years and using the knowledgefrom several previous models of the Site.

The model looked at the following future scenarios:

• continued current conditions;

• continued regional drought;

• continued current conditions with additional bedrock pumping at the Old CrosscutCanal;

• bedrock pumping only at the Old Crosscut Canal;

• increased on-site pumping; and

• continued current conditions with reinjection.

The conclusions drawn from the model results indicated that with the exception ofbedrock pumping at the OCC simulation all the scenarios predict that capture will bemaintained into the future. The continued current conditions and the continued regionaldrought scenarios are essentially the same with respect to operations and show that thecurrent operations will continue to be adequate for at least the next several yearsregardless of the drought. The Report goes on to say in summary that the modelpredictions indicate that the OU1 system will continue to maintain capture with currentrates or gradually reduced rates into the foreseeable future. Increasing on-site pumpingwould enhance mass removal. The other scenarios are feasible, but do not significantly

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enhance the current system.

A detailed review and assessment of the capture analysis is provided in Sections 7 and 8.

3.3.13 Recovery of Dense Non-Aqueous Phase Liquid

In 1994, Freescale initiated a program of weekly to bi-weekly recovery of DNAPL froma monitor well (MP-3-D) located in the Courtyard. MP-3-D is screened in the bedrock ata depth of 162 feet bgs. Through the calendar year 2005, approximately 9 gallons ofDNAPL has been removed, which equates to approximately 166 pounds of TCE.

3.3.14 Courtyard Soil Remedy Implementation

From December 20, 1990 to May 4, 1993, an SVE pilot test was completed at theCourtyard Area. On May 7, 1992, the installation of the Courtyard SVE system wascompleted. The Courtyard SVE blowers were located within the groundwater PTP(Figure 2), and the extracted soil vapor was treated through the existing vapor phasecarbon vessels used during the initial groundwater PTP testing. From May 8 through May13, 1992, the baseline data was collected for the Courtyard SVE system. The pilotprogram was then initiated on September 21, 1992 and completed on March 31, 1993.Upon completion of the pilot program, the Courtyard SVE system was never restarted.

Numerical models were used to evaluate the Courtyard SVE pilot test and to estimate thepotential for residual VOCs in the vadose zone beneath the Courtyard to impact shallowgroundwater. The results of the groundwater impact model were: (1) TCE and PCEconcentrations in the vadose zone near the SVE well are nearly in equilibrium withcurrent groundwater concentrations; (2) SVE was ineffective in eliminating TCE andPCE from vadose zone soils located near the SVE well; (3) VOCs in this zonepresumably reside in low-permeability soils that are not amenable to remediation bySVE; and (4) predicted TCE groundwater concentrations at the property boundary, thatwould result from the residual vadose VOCs in the Courtyard, are nearly two orders ofmagnitude less than existing shallow groundwater concentrations beneath the Site.

In April 1997, a report on the evaluation of the Courtyard SVE system was submitted toADEQ. The Report concluded that additional SVE in the Courtyard area was consideredto have no significant remedial benefit because: (1) SVE was demonstrated to beineffective in eliminating the residual vadose VOCs believed to be present in the lowpermeability soils located near the SVE well, (2) the potential impact of residual vadoseVOCs on existing shallow groundwater conditions would be negligible; and (3) it wasdemonstrated that continued SVE operations were not economically feasible. Freescalesubmitted a letter requesting closure of the Courtyard SVE on April 30, 1998. ADEQreviewed Freescale’s request and recommended preparing a workplan for collection ofsoil or soil gas samples. Once the workplan is finalized, ADEQ will determine anevaluation criteria based on Arizona’s Soil Rule. Arizona’s Soil Rule is in the process ofbeing revised. Once the Soil Rule is promulgated, the CO will be amended to include thenew provisions.

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3.3.15 Voluntary SWPL Groundwater Remedy Implementation

In 1991, Freescale initiated the investigation of groundwater and the implementation of avoluntary groundwater extraction program within the SWPL Area. The voluntaryprogram was implemented because the results of the periodic sampling of well DM-201,located within the SWPL Area (Figure 2), indicated that TCA and 1,1-DCE wereincreasing in concentrations.

The following RI activities were performed in the SWPL Area:

• a soil gas investigation was conducted at 23 locations within the SWPL area;

• on June 28, 1991, a pump was installed in well DM-201-OB1 and groundwaterextraction activities were initiated;

• during the months of January and February 1992, groundwater extraction wellswere installed and completed;

• during the month of May 1992, the extraction wells were put into operation;

• on September 11, 1992, a Final Draft of the SWPL RI Work Plan was submittedto ADEQ. The Work Plan provided additional investigative activities tocharacterize the lateral and vertical extent of VOCs in the SWPL area and todevelop a technical foundation for future remedial activities.

In May 1993, the results of the investigative activities performed at the SWPL area werepresented in a draft report. The specific objectives of the SWPL RI were: (1) to delineatethe lateral and vertical extent of VOCs in the groundwater; (2) characterize thegroundwater flow patterns in soil and bedrock; and (3) develop remedial alternatives forSWPL. The following contains summaries of key findings to the May 1993 Report.

• The groundwater flow gradient in the SWPL Area is to the southwest and iscurrently altered by groundwater pumping. Groundwater flow in the alluvialaquifer is controlled by the saturated thickness of the alluvium and by thecontoured bedrock surface. Groundwater flow in the bedrock is controlled bystructural discontinuities in the rock mass. Zones of increased bedrock fracturingtypically strike northwest/southeast and dip relatively steeply to the southwest.

• The former sump in the Building A-D chemical mixing and bottling room appearsto be the principal source of TCA and DCE found in the groundwater at theSWPL Area. The source of PCE and TCE contamination in the SWPL Area isunknown. The lateral extent of TCA, DCE, and PCE in groundwater is defined tothe northeast, northwest, and southwest directions but not toward the southeast.The lateral extent of TCE in groundwater appears to be adequately defined to thesouthwest, but not in the other directions. The vertical extent of VOCconcentrations is defined at the southern boundary of the SWPL Area.

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• Elevated concentrations of the inorganic constituents (arsenic, fluoride, andnitrate) were identified in groundwater in the SWPL Area and immediatelydowngradient. However, the Report states that there is no demonstratedconnection between this observation and Freescale’s disposal practices in theSWPL Area. These elevated concentrations may be related to background oragricultural activities conducted in the area prior to Freescale acquiring the site.

• The RI Report also provided an evaluation of the SWPL groundwater extractionsystem which indicated that the current extraction wells are effective incontaining and remediating VOCs in the groundwater.

3.3.16 SWPL Soil Remedy Implementation

The SVE system was required by the OU1 ROD. On September 23, 1992, a draft In-SituAS/SVE System Field Test (Pilot Test) Plan was submitted to ADEQ for the SWPLArea. ADEQ approved this plan and in January 1993, three SVE wells (TW-001 throughTW-003) and one air-sparging (AS) well (AS-002) were installed within the SWPL Area.

From February 11 through February 25, 1993, the SWPL SVE and AS/SVE pilot testswere conducted in the parking lot and Building A-D. The results were reported to ADEQon April 21, 1995. The pilot tests confirmed that these technologies proved effective inreducing VOC contamination in the vadose zone at the SWPL Area. In addition, duringthe 4.5 days of testing, 265 pounds of VOCs were recovered around Building A-D. Basedon these findings, ADEQ recommended that Freescale evaluate applying the AS/SVEtechnology on a larger scale in the Building A-D area to remove residual VOCs in thevadose zone and reduce VOC contamination in the groundwater. It was alsorecommended that the current SWPL groundwater treatment system be maintained tocontinue containment of VOC contamination on-site and keep the water table lowered toenhance the effectiveness of the AS/SVE operations.

On April 25, 1995, the design report, plans, and specifications detailing the proposedpermanent SVE/AS system were submitted to ADEQ. The CO required that Freescaleimplement the SVE system; however, Freescale independently proposed the use of an ASsystem to enhance the remediation of VOCs in the groundwater at the SWPL Area.Freescale operated the AS system voluntarily following approval by ADEQ in a letterdated June 1, 1995.

Construction of the SWPL AS/SVE system was conducted during June throughNovember 1996 at which time the system was started-up and continued operationsthrough April 1997. After shutdown in April 1997, the system was never restarted.Detailed descriptions of the SWPL AS/SVE systems are provided in Section 4.1.2 of thisReport.

On December 22, 1998, a report on the evaluation of the SWPL SVE system wassubmitted to ADEQ. The purpose of this Report was to evaluate the construction,start-up, and operation of the SWPL SVE system and assess its effectiveness in reducing

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VOCs within the vadose zone. The Report specified that the SWPL SVE system wasoperated for a period of five months. During that time period, extracted VOCconcentrations in the extraction wells declined to concentrations less than 2 parts permillion by volume (ppmv). Cyclical SVE operations within the source area did notgenerate a substantial increase in VOC mass removal and minimal rebound wasobserved. Extracted VOC concentrations decreased to steady state levels within 12 hoursof cyclical operation commencement. The Report concluded that based on the reductionin extracted VOC concentrations and the reduced vadose zone concentrations, SVEoperations have successfully achieved the objective of removing residual VOCs in thesoil. Freescale submitted a letter to ADEQ on March 21, 2001, requesting closure of theSWPL SVE system. On November 15, 2002, ADEQ granted closure for soil cleanup inthe SWPL Area (Appendix D).

3.3.17 First Five Year Review

In September 1995, ADEQ completed the First Five-Year Review Report for theMotorola 52nd Street Superfund Site. Although the review concluded that the interimremedy was effective in the alluvial portion of the aquifer, ADEQ expressed concernsabout the groundwater containment system attaining complete capture of the plumewithin bedrock. Specifically, well DM-603, immediately downgradient from theextraction wells, had a 40% increase in the concentration of TCE from the sampling portbelow the bedrock/alluvium interface during the past three quarters. TCE increased from8,100 :g/L to 20,000 :g/L. Review of TCE concentration data from 1991 to 1995indicated that the current concentration (at the time of the 1995 review) was at a historichigh. It was believed that the increasing concentrations of TCE were coming from asource upgradient to DM-603 (most likely migrating from the Motorola 52nd StreetFacility) rather than being drawn back from downgradient as an artifact of the extractionwells. On November 16, 1995, EPA accepted and approved the Five-Year ReviewReport.

3.3.18 MI52 Model Documentation Report

In February 1996, Freescale submitted the MI52 Model Documentation Report forMotorola Inc. The purpose of the Report was to define the maximum extent ofgroundwater contamination by VOCs attributable to the Motorola 52nd Street Facility.The Report presented models of predicted groundwater flow and contaminant transport ofVOCs from Freescale and other sources.

3.3.19 Second Five Year Review

In September 2001, ADEQ completed the Second Five-Year Review Report for theMotorola 52nd Street Superfund Site. Although the review concluded that the interimremedy was effective in the alluvial portion of the aquifer, ADEQ identified thefollowing concerns:

• the pump and treat system was not significantly effective in reducing the levels ofcontaminants due to the DNAPL in fractured bedrock;

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• a downward gradient and increasing TCE concentration trend at monitor wellDM-606 may indicate that deep bedrock capture in that area is inadequate;

• increasing concentration in the northernmost three extraction wells may indicatethat the system may need modification to address capture of contaminants withinthe bedrock;

• increasing concentrations in shallow bedrock ports in monitor wells DM-603 andDM-605 may be indicative of TCE contaminant migration from deeper bedrockfractures;

• no monitor wells are located immediately downgradient of the capture zone thatcan be used to confirm that the plume is contained. This is a concern especiallysince the alluvial aquifer is becoming dewatered;

• concentrations of TCE detected in monitor wells EW-18 and DM-125 suggest thatthe northern boundary of the plume is not completely defined;

• groundwater data indicated that vinyl chloride was detected more frequently andat higher concentrations in some of the monitor wells associated with OU1; and

• as water levels decline and the alluvium is dewatered, ADEQ was concerned thatthe effectiveness of the bedrock capture may be reduced.

On September 28, 2001, EPA accepted and approved the Second Five-Year ReviewReport. Freescale provided comments on the Second Five-Year Review Report in a letterdated March 28, 2002.

ADEQ issued a Letter Report Update to the OU1 Second Five-Year Review on August14, 2003. The Letter Report provided a summary of: (1) the established remedial actionobjectives (RAOs), (2) the findings from the Second Five-Year Review, (3) workconducted since the Second Five-Year Review, (4) current and future protectivenessstatements, and (5) additional actions to be taken with a proposed schedule. Freescaleconducted an evaluation of the OU1 system during shut down for maintenance inDecember 2001 through February 2002. In addition, Freescale evaluated the extractionwells at the Courtyard. After evaluating the work Freescale conducted in 2001 and 2002,ADEQ determined the following for OU1:

• the OU1 remedy was protective of human health and the environment;

• the remedy is currently meeting the RAOs (to capture contaminants ingroundwater and to reduce the concentration of contaminants in groundwater).

However, ADEQ noted the following concerns:

• if current site conditions persist, the remedy may not be protective long-term;

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• the issue of dewatering the alluvium will require both extraction and treatmentsystem design changes in order to handle the reduced flow and yet continue toprovide capture of bedrock contamination;

• the indoor air pathway assessment will need to be completed before a futureprotectiveness statement can be determined.

3.3.20 Treatment System Shutdown

In April 2003, Freescale shutdown the OU1 treatment system after discovering cracks inthe carbon vessels that serve as air emission controls. As a result of the shutdown, ADEQrequested that Freescale conduct an evaluation of the potential impacts on groundwaterflow and contaminant migration. The data used for this evaluation was collected during aprevious shutdown from December 2001 to February 2002. Freescale reviewed the dataand determined that the shut down is not expected to have any adverse impacts ondowngradient water quality conditions as the system will recapture the low level VOCswest of the extraction system. The evaluation showed that after more than one month,groundwater in the vicinity of the downgradient DM-600 series wells was still flowing ina southeasterly direction. In addition, Freescale determined that the maximum distancegroundwater could travel during the shutdown would still be within the previous capturezone and that the capture zone would be re-established quite quickly after the wells areturned on again.

3.3.21 Groundwater Remedial Alternative Analysis

Freescale submitted a Groundwater Remedial Alternatives Analysis (GRAA) Report onSeptember 30, 2005 and an Addendum to Groundwater Remedial Alternatives Analysisin December 2005. The GRAA provided a focused evaluation of groundwater remedialalternatives at the former Motorola 52nd Street Facility based on current contaminantdistribution and remediation progress.

Freescale also developed a groundwater flow model to analyze future systemeffectiveness under continuing groundwater decline. The model evaluated the followingfuture scenarios: (1) continued current conditions, (2) continued regional drought, (3)continued current conditions with additional bedrock pumping at the Old Crosscut Canal,(4) bedrock pumping only at the Old Crosscut Canal, (5) increased on-site pumping, and(6) continued current conditions with reinjection. The only simulation that did not predictthat capture would be maintained in the future was the bedrock pumping only at the OldCrosscut Canal scenario.

ADEQ is currently in the process of reviewing these documents. ADEQ met withFreescale on March 7, 2006 to discuss the Reports. At that meeting, Freescale agreed toprepare a work plan for a pilot aquifer test in bedrock.

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4.0 REMEDIAL ACTIONS

4.1 Remedy Selection

ADEQ’s LOD and CO, and EPA’s ROD describes the selected remedy as the Alternative“C”. Alternative “C” is an interim remedy designed to meet the following RAOs whichwere established to provide a cleanup consistent with a more comprehensive, finalsolution:

• protect public health and the environment by recovering and treatingcontaminated groundwater;

• reduce current contamination levels in groundwater;

• provide containment of contaminated groundwater encountered east of the OldCrosscut Canal;

• expedite recovery of contaminated groundwater between the Old Crosscut Canaland the Freescale plant on 52nd Street;

• assure beneficial use of contaminated groundwater that is extracted and treated;

• incorporate permanent solutions and alternatives and innovative technologies inthe cleanup process to the extent possible. In accordance with the LOD and ROD,Alternative C consists of the following basic components:

• on-site extraction and treatment of groundwater from the Courtyard and 50thStreet Area designed to reduce or eliminate contaminant migration;

• on-site extraction and treatment of vapor phase organic contaminants from soilsfrom the Courtyard and 50th Street area, the ATP, and SWPL area;

• off-site extraction of groundwater designed to contain contaminant migration atthe Old Crosscut Canal;

• on-site treatment of extracted groundwater from on-site and off-site wells; and

• use of all treated groundwater at the Motorola 52nd Street Facility.

The OU1 interim remedy evaluated during this five-year review consists of: (1) a SVEremediation system within the Courtyard that included one extraction well; (2) a SVEremedial system within the SWPL Area; and (3) four on-site extraction wells and nineoff-site extraction wells which are all piped to the IGWTP. In addition to these OU1remedial systems, Freescale voluntarily initiated a groundwater remediation programwithin the SWPL Area that included AS wells combined with the SVE wells and twelvegroundwater extraction wells, all of which are also connected to the IGWTP. The generallocations of these remedial systems are shown in Figure 2.

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4.1.1 Groundwater Remedy

The groundwater extraction system consists of 16 on-site and 9 off-site extraction wells.The 16 on-site extraction wells are intended to reduce the high concentrations within thesource areas. The 9 off-site extraction wells provide hydraulic containment west of thesite to approximately the Old Crosscut Canal. There are also a total of 68 monitoringwells within OU1, 27 of which are multiport or Westbay wells.

The IGWTP system consists of two air strippers, four liquid phase GAC vessels and onevent scrub canister. Figure 3 provides a process flow diagram of the IGWTP.Groundwater from the extraction wells is pumped at a current average rate of 283 gpm tothe IGWTP where the groundwater enters one of two 17,080 gallon storage (surge) tanks.From the storage tanks, acid and biocide treatment is applied to the groundwater toinhibit hardness and bio-fouling in the primary air stripper (AS-201). The water thenpasses through a static mixer and enters AS-201. Effluent water from AS-201 is thenpumped to a secondary air stripper AS-301 for additional treatment. Effluent water fromAS-301 is then pumped through two liquid phase GAC vessels connected in series forVOC polishing. After VOC polishing is completed, the water is then routed to a storagetank and used in the Facility RO/DI plant and/or for use in the Facility cooling towers.The stripped effluent vapor from AS-201 is routed through a dehumidifier to reduce therelative humidity of the vapor stream. VOC laden vapors are then treated by one vaporphase vent scrub canister. The spent vapor phase GAC is shipped off-site for regenerationby the vendor. Vapors from the discharge of the GAC are routed to AS-301. The spentliquid phase GAC and all recovered waste solvents are shipped off-site as a hazardouswaste. Based on a review of hazardous waste manifests submitted by Freescale, thequantity of recovered solvents generated on a monthly basis ranges from 100 to 150pounds.

4.1.2 Soil Remedy

The Courtyard SVE remedial system was never modified from the pilot treatment systembecause the effectiveness evaluation performed by Freescale (See Section 3.3.14)concluded that additional SVE in the Courtyard area was considered to have nosignificant remedial benefit. The Courtyard SVE system consisted of one SVE well(EX-1) that was connected to a vapor treatment system within the PTP area. The processflow diagram for this system shows that the extracted vapor from the well was routed tothe vapor treatment system consisting of two vapor phase GAC vessels which remove theVOCs prior to discharge into the atmosphere (Figure 4). The system was designed toproduce an effective radius of influence of 25 feet. The SVE system was in operationfrom September 21, 1992 to March 31, 1993.

The CO required treatment of soil vapor at the ATP. No active soil remediation has beenconducted in the ATP area to date. Data collected by Freescale suggests that soil vaporextraction is not needed at the ATP; however, ADEQ and Freescale have agreed toconduct a soil investigation pending the revision of Arizona’s Soil Rule.

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The SWPL soil remediation system consisted of six combined SVE/AS wells and sixGAC vessels. The process flow diagram for this system is attached as Figure 5. Air isinjected via the AS wells into the groundwater with an air compressor. Prior to injection,the air goes through an oil filter and air dryer. The VOCs in the groundwater werevolatilized and migrate up to the vadose zone. VOCs in the vadose zone were thenextracted by the SVE wells that were connected to a blower and routed to the vaportreatment system housed within Building A-D. The vapor treatment system consists ofsix vapor phase GAC vessels which remove the VOCs. The treated air is then routed to aheat exchanger prior to discharge into the atmosphere. The SVE system was designed toproduce an effective radius of influence from 30 to 40 feet. The AS system was designedto produce an effective radius of approximately 90 feet of sparging influence. TheSVE/AS system was in operation from November 1996 through April 1997.

4.2 Remedy Implementation

The history overview of the implementation of the IGTWP is provided in Section 3.3.8.The IGWTP has been in operation since July 1992. The groundwater extraction system isdesigned to treat approximately 810 gpm and receives groundwater from 23 extractionwells. Currently, due to dewatering of the alluvium, the IGTWP is operated atapproximately 283 gpm. Wells DM-313, DM-312, and DM-311 were taken off-line (withADEQ’s approval) in the summer of 1993, November 1995, and April 2004, respectively,because VOC concentrations decreased to below the MCLs. These wells are currentlybeing used as monitor wells. As of December 31, 2005, the on-site treatment systemprocessed approximately 2.5 billion gallons of groundwater, from which approximately17,265 pounds of VOCs have been removed.

The history overview of the implementation of the Courtyard SVE system is provided inSection 3.3.14. Since the completion of the pilot test (March 31, 1993) the system has notbeen in operation and recommendations have been made by Freescale not to conduct anyfurther SVE remediation within the Courtyard Area. Evaluation of the Courtyard SVE isprovided in Section 6.4.5 of this Report.

The history overview of the implementation of the SWPL SVE/AS system is provided inSection 3.3.16. The SWPL SV/AS system was operated from December 3, 1996 toJanuary 20, 1997. The system was operated with all extraction wells open at all timesuntil March 3, 1997 when cyclical operation of the SVE/AS system was initiated.Cyclical operation of the system within the source area did not generate a substantialincrease in VOC mass removal and minimal VOC concentration rebound was observed.SVE/AS operation was completed on April 18, 1997 when apparent asymptoticconcentrations were achieved. After SVE treatment, soil gas VOC concentrationsdecreased substantially when compared to the soil gas concentrations prior to treatment.On March 21, 2001, Freescale provided a written request for a No Further Action (NFA)of the continued soil remediation at the SWPL Area. ADEQ determined that the soilcleanup in the SWPL Area was complete in a letter dated November 15, 2002 (AppendixD).

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4.3 System Operations

The Courtyard SVE and SWPL AS/SVE systems are not currently in operation. For theoperation of the IGWTP system, Freescale retained the services of Clear CreekAssociates to conduct all monitoring activities described in Section 3.3. Dailymaintenance activities are performed by Gutierrez-Palmenberg, Inc. (GPI) in accordancewith the updated August 2000 O&M Manual for the IGWTP.

From 2001 to 2002, O&M costs for the IGWTP increased from approximately $577,703to $1,206,523. Freescale stated that the increase was related to the ONSemiconductor-Motorola separation and represented the accrual of land and utility costsnot previously captured since the remedy was integrated into the manufacturingoperations at the former Motorola 52nd Street Facility. From 2002 to 2005, the O&Mcosts were generally consistent. Table 2 provides the annual O&M costs from 2001 to2005. These costs do not include other response costs that were incurred for OU1 (e.g.,agency oversight).

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5.0 PROGRESS SINCE THE LAST FIVE YEAR REVIEW

5.1 Protectiveness Statement from Second Five-Year Review

The Second Five-Year Review for OU1 was completed by ADEQ on September 28,2001. At the time of the Report, a protectiveness determination of the OU1 remedy couldnot be made until further information was obtained. ADEQ provided a list of actions thatneeded to be competed before a protectiveness statement could be issued.

A follow-up Letter Report was issued by ADEQ on August 14, 2003. ADEQ issued aprotectiveness statement after evaluating the work conducted by Freescale in 2001 and2002. ADEQ issued the following statement with regard to the OU1 remedy:

ADEQ has determined that the OU1 remedy is currently protective of humanhealth and the environment. The remedy is currently meeting the Remedial ActionObjectives: to capture contaminants in groundwater and to reduce theconcentration of contaminants in groundwater. However, if current siteconditions persist, ADEQ cannot state that the remedy will continue to beprotective in the long-term. The issue of dewatering the alluvium will require bothextraction and treatment system design changes in order to handle the reducedflow and yet continue to provide capture of bedrock contamination. Additionally,the indoor air pathway assessment will need to be completed before a futureprotectiveness statement can be determined.

5.2 Status of Recommendations and Follow-up Actions from Last Review

Table 3 presents a summary of the status of the recommendations and follow-up actionsfrom the Second Five-Year Review. Most of the recommendations and follow-up actionswere addressed by Freescale; however, several of the issues raised continue to beproblematic. Monitor well coverage downgradient and to the north of the Old CrosscutCanal (EW-18 area) remains sparse, especially in bedrock. Additionally, the verticalgradients observed in DM-606 remain a concern to ADEQ.

ADEQ is concerned that Freescale is operating from a fundamentally different conceptualsite model for OU1, particularly with regard to bedrock. ADEQ and Freescale havediscussed these issues at a recent meeting to discuss the Groundwater RemedialAlternative Analysis, Motorola 52nd Street OU1, Phoenix, Arizona Report. Freescale ispreparing a workplan to address the bedrock conductivity issues.

Finally, the status of soil remediation projects at the ATP and Courtyard are currentlyincomplete. Once the Arizona Soil Rule is finalized, ADEQ will develop evaluationcriteria that will be used to determine whether the Courtyard Area soils can be closed out.After the Soil Rule is promulgated and the CO amended, Freescale should prepare aworkplan to evaluate the Courtyard Area.

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Freescale has indicated that soil data in the ATP Area suggests that SVE remediationmay not be applicable. ADEQ and Freescale have agreed to investigate the ATP Areafollowing completion of the Courtyard investigation. The evaluation criteria establishedfor the Courtyard will also be applied to the ATP Area.

5.3 Results of Implemented Actions

The following paragraphs discuss some of the results of the implemented actions fromthe Second Five-Year Review. Table 3 provides a list of the actions taken and outcomesfor each issue raised during the Second Five-Year Review.

Freescale provided an evaluation of several of the issues raised during the SecondFive-Year Review in the 2001 Effectiveness Report for OU1.

Freescale also provided an evaluation of soil data in the SWPL Area to ADEQ andrequested closure on March 21, 2001. ADEQ determined that soil cleanup in the SWPLArea was complete and issued a No Further Action letter in November 2002.

Freescale provided documentation regarding the abandonment of the Turnage and Williswells.

Freescale also addressed the issues regarding the IGWTP following the site inspection.GPI conducts routine maintenance activities and replaces worn or damaged equipment asneeded.

5.4 Other Progress Made During the Review Period

The following progress was made in the operation of OU1 since the last review:

• continued operation of the IGWTP resulting in additional recovery of VOCs inthe groundwater. As of December 31, 2005, approximately 17,265 pounds ofVOCs have been removed. Approximately 3,871 pounds have been removedduring this review period;

• additional recovery of DNAPL from well MP-03-D; approximately 9 gallons ofDNAPL have been recovered as of December 31, 2005. This equates toapproximately 166 pounds of VOCs. Approximately 3.4 gallons have beenremoved during this review period;

• DM-311 was taken off-line (with ADEQ’s approval) in April 2004 because VOCconcentrations decreased to below MCLs.

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6.0 FIVE-YEAR REVIEW PROCESS

6.1 Administrative Components

Section 121(c) of CERCLA requires that the lead regulatory agency conduct a review ofany remedial action selected that results in any hazardous substances, pollutants, orcontaminants remaining at the Site no less often than every five years. The 1988 LODand ROD for the Motorola 52nd Street Superfund Site allow the hazardous substances toremain on Site; therefore, five year reviews are required by statute. Guidance for thisreview is provided in OSWER Directive 9355.7-03B-P Comprehensive Five-YearReview Guidance, dated June 2001, EPA 540-R-01-007.

The first five-year review was completed on September 5, 1995. The second five-yearreview was completed on September 28, 2001. The purpose of the five-year review is todetermine whether human health and the environment are adequately protected by theexisting remedial action. The five-year review will be submitted to EPA for approval.Once approved, EPA will provide a concurrence letter on the findings.

The Motorola 52nd Street five year review was lead by Kris Paschall, Project Manager ofADEQ, who provided oversight of the review process that was conducted by LFR(ADEQ’s consultant). The following team members took part in the review:

• Kris Paschall, ADEQ Project Manager;

• David Haag, ADEQ Project Hydrologist;

• Robert Forsberg, LFR Project Manager;

• Brad Cross, LFR Principal Hydrogeologist;

• Ned Overs, LFR Professional Engineer;

• Michael Nesky, LFR Senior Engineer;

• John Kivett, LFR Senior Hydrologist;

• Laura Malone, LFR Senior Project Scientist;

• Nadia Hollan, EPA Project Manager.

The five-year review consisted of the following activities: (1) development of a workplan and review of relevant documents (Appendix A); (2) interviews with appropriateoperations staff, state and federal agencies, local government officials, and concernedcommunity members; and (3) a site inspection. The review period was from September30, 2001 through July 2006.

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6.2 Community Involvement

A public notice regarding the initiation of the forthcoming review was mailed to theMotorola 52nd Street Superfund Site mailing list in April 2006 (See Appendix E). Thefinal report is available at ADEQ and the local site repositories which are located at theCentral Branch and the Saguaro Branch of the City of Phoenix public libraries. ADEQwill provide a brief summary of this Report to community members by holding a publicmeeting and/or distributing a fact sheet.

Additional community involvement activities during this five-year review periodincluded periodic Community Advisory Group (CAG) meetings, update of theCommunity Involvement Plan (CIP), and involvement with the Technical Advisory Grant(TAG) Gateway Neighborhood Coalition.

The CIP was update in March 2002 and again in July 2004. ADEQ conducted severalinterviews with the OU1 community to gather information for both of these updates. Theprimary concerns of the community in OU1 related to having access to enoughinformation about the project, health impacts, the current status of contamination, andunderstanding the proposed cleanup.

Both EPA and ADEQ worked with the TAG recipient Gateway Neighborhood Coalitionduring this review period. In addition, EPA and ADEQ have held periodic CAG meetingsto discuss activities and the status of OU1. Minutes from these CAG meetings areavailable for review in the repositories and ADEQ’s website.

6.3 Document Review

The following primary site documents have been reviewed:

• Baseline Health Risk Assessment, Motorola 52nd Street Facility, Phoenix,Arizona, prepared by ADHS, November 1992

• Letter of Determination, Operable Unit One, September 1988

• Record of Decision, Operable Unit One, September 1988

• Consent Order, Operable Unit One, June 20, 1989

• Technical Memorandums and supporting information prepared by Clear CreekAssociates on behalf of Freescale

• Integrated Groundwater Treatment System Operation and Maintenance Manual,Revision 7, August 2000

• The following routine documentation: Semiannual PQGWWP GroundwaterMonitoring Reports, Annual OU1 Effectiveness Reports (2001-present)

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6.4 Data Review

The following sections briefly discuss the main data sources reviewed for the five-yearreview evaluation. A review of ARARs is discussed in Tables 3, 4, and 5.

6.4.1 Groundwater Data Review

The groundwater monitoring program conducted at the OU1 Area includes the networkof monitor wells identified in the Groundwater Monitoring Plan, 52nd Street SuperfundSite, Operable Unit 1 Area, prepared by Dames & Moore, dated January 1998. Thesemonitor wells are used to collect groundwater elevation and water quality data from thealluvium and bedrock upgradient, downgradient, and cross-gradient from the site. Thelocations of the wells are shown on Figure 2. Groundwater samples collected from thesewells are analyzed for VOCs and selected inorganic compounds semiannually in Marchand September. Hydrographs of groundwater elevations and concentrations for selectedwells are provided in Appendix F.

The main analytes that are detected most frequently exceeding their respective MCLs areTCE, PCE, 1,1-DCE, cis-1,2-DCE, vinyl chloride, and TCA. Since the CO did notestablish groundwater cleanup ARARs, the exceedances of groundwater standards of anycompound in any well used to monitor OU1 was not recognized as a deficiency in thisreview. Since the interim remedy was primarily implemented to reduce the concentrationof contamination at the source and to capture the migrating plume at the Old CrosscutCanal, the groundwater data review evaluated trends in groundwater concentrations andelevations in key areas on and off site. Data from monitor wells downgradient of the OldCrosscut Canal extraction wells were used to evaluate the effectiveness of capture and todetermine whether the plume was being contained at the Old Crosscut Canal.

6.4.2 Treatment Plant Data Review

Treatment plant influent and effluent data are collected on a bi-monthly basis. Theeffluent results were compared to the requirements of the ROD, LOD, and CO. Based onthe data provided by Freescale, the treated effluent met the requirements of the ROD,LOD, and CO.

Available copies of historical design and engineering documents, record drawings,treated effluent monitoring plan, the PQGWWP, the IGWTP effluent monitoringrecords/data and air emissions data, carbon change out records, waste profiling data, andmanifests of the spent carbon and recovered solvents sent off-site for regeneration andrecycling were reviewed. During the inspection, LFR reviewed the IGWTP records,including: daily/bi-weekly/monthly operating logs, pH/ORP calibration logs,maintenance logs, and other documents to assess operation and maintenance compliance.

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6.4.3 OU1 Evaluation – Shutdown and Monitoring Report

This Report evaluated the potential impacts of the treatment system shutdown ongroundwater flow and contaminant migration. The data in this Report was used toevaluate the effectiveness of capture.

6.4.4 OU1 Evaluation Model Report

LFR reviewed the OU1 Evaluation Model Report dated September 2005. Model resultswere used to evaluate the long term effectiveness and sustainability of the existingtreatment system.

6.4.5 SVE Evaluation Remedial Completion Evaluation

Motorola’s SVE evaluation reports and requests for an NFA determination for theCourtyard and SWPL SVE treatment systems were reviewed. ADEQ granted closure forsoil cleanup at SWPL in a letter dated November 15, 2002. ADEQ requested additionalinformation regarding the closure request for the Courtyard; confirmatory soil and/or soilgas samples must be collected. The results of the sampling will be compared to theappropriate standards to determine if closure can be granted. Arizona’s Soil Rule is in theprocess of being revised. Once the Soil Rule is promulgated, the CO will be amended toinclude the new provisions.

6.5 Interviews

The following individuals were interviewed for OU1 during this five-year review processby personal contact or by telephone:

• Bob Atkinson, Director of Health & Safety, ON Semiconductor –Telephone interview on May 8, 2006.

• Tom Suriano, Remediation Project Manager, Freescale Semiconductor –Interviewed on May 10, 2006 at the ADEQ office.

• Nadia Hollan, Project Manager, EPA – Interviewed on May 10, 2006 atthe ADEQ office.

• Martha Breitenbach, CAB Member – Telephone interview on May 23,2006.

• Karen O’Regan, Environmental Programs Director for the City of Phoenix– Interviewed May 25, 2006 at the ADEQ office.

• George Ring, Robert Frank and Phil Burke of CH2M Hill (representingTroy Meyer of Honeywell) – Interviewed on May 30, 2006 at the ADEQoffice.

• Larry Rodriquez, Supervisor, GPI – Provided a written response. • Leo Wilson, Operator, GPI – Provided a written response. • Donn Stoltzfus, Environmental Program Specialist, City of Phoenix –

Telephone interview on July 21, 2006.

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The following individuals were invited to interview and ADEQ either received a declineto interview or did not receive a response:

• Steve Brittle – Don’t Waste Arizona • Daniel Casiraro – Salt River Project • Mario Castenada – Gateway TAG technical consultant • Jeff Conover – Walker Power • Janet Corrigan – Paul McCoy’s Laundry • Gine Flury – AdobeAir • Andrew Frisbie – Wabash National • Linda Furlough – Arvin Meritor • Richard Guimond – Motorola • John Held – Phoenix Newspapers • Mark Hess – Cooper Industries • Judith Heywood – APS • Kenneth Hodson – BDR Liquidating • Ed Honig – Union Pacific Railroad • Michael Johnson – City of Phoenix Councilman • John Maris – D-Velco • Scott Miller – AZ. Department of Water Resources • Teresa Olmstead – ITT Industries • Tommy Padgett – Citizen – Requested interview, but was not available • Cynthia Parker – City of Phoenix Aviation Department • Stephen Smith – BDR Liquidating • Greg Stanton – City of Phoenix Councilman • Douglas Watson – Joray

The detailed accounts of the interviews are presented in Appendix G, which are brieflysummarized in the following paragraphs.

Bob Atkinson, Director of Health and Safety, ON Semiconductor. During Mr.Atkinson’s interview, he did not identify any issues associated with OU1. He did statethat the project (OU1) appeared to be going quite well and is managed appropriately byMotorola.

Mr. Tom Suriano, Remediation Project Manager, Freescale Semiconductor. Mr.Suriano is responsible for overseeing all O&M, monitoring, and reporting activitiesperformed at OU1. Excerpts of his responses are as follows. He is familiar with allaspects of the project and was familiar with all O&M and monitoring activities for OU1.The OU1 remedy has been successful at achieving the remedial action objectives. Therehave been no significant O&M problems or difficulties within the last 5 years that haveaffected the protectiveness or the effectiveness of the remedy. Approximately 3 yearsago, a change out of air controls occurred and the vapor phase carbon was replaced, butthese actions in no way affected the protectiveness of the system. Flow rates have beendecreased due to the declining water levels. None of these changes have adverselyimpacted the ability of OU1 to maintain capture.

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Nadia Hollan, Project Manager, EPA Region 9. Ms. Hollan provides support to ADEQfor the OU1 activities. Excerpts of her responses to the interview are as follows. TheOU1 remedy is an interim containment remedy, selected in 1989 and operated byFreescale. OU1 is effective for containing alluvium contamination; however, there aresome concerns of its effectiveness in bedrock. Parts of the remedy have yet to beevaluated for effectiveness and OU1 is not a final remedy and does not address allaspects. Periodically, there have been inquires made to EPA on OU1. Specific detailscould not be remembered, however, the majority of the inquiries were minor issues andthese were referred to ADEQ. The only potential changes to future EPA guidance may befor the selection of institutional controls. No other opinions were given on the O&M ofOU1. In terms of comments and recommendations to improve the effectiveness of OU1,Ms. Hollan stated that the public record reflects EPA’s issues. Ms. Hollan also stated thatthe evaluation of the vapor intrusion pathway is an issue and needs to be completed. Ms.Hollan stated that EPA continues to work with ADEQ regarding on-going captureoptimization.

Martha Breitenbach, CAG Member. Ms. Breitenbach has been a member of the CAGfor approximately 5 years and participates in the CAG meetings. Excerpts of herresponses to the interview are as follows. The OU1 remedy is meant to pump and treatthe groundwater and understands that the treated water is sold to ON Semiconductor foruse in the plant. Overall impression of the system is not favorable as she stated that theplume is growing. Ms. Breitenbach is extremely upset and disappointed that there isn’t amore aggressive approach to cleaning up the contamination. She expressed concern overthe soil contamination that continues to be a source of groundwater contamination andwould like to see this issue addressed. She also expressed concern that the sludge in thebedrock is still contaminated and that this is an outstanding issue. Ms. Breitenbach statedthat she has been kept well informed of the issues at OU1. Recommendations were madeto be more aggressive in the approach and she would like to see the treated waterreturned to the ground since we’re in a drought.

Karen O’Regan, Director of the Environmental Programs Department, City ofPhoenix. Ms. O’Regan is a representative of the City of Phoenix and is involved inissues surrounding the redevelopment of the Site. Excerpts of her responses to theinterview are as follows. OU1 is a groundwater containment system. The treated water issold to ON Semiconductor for use in the plant. OU1 is fairly effective, but there is aconcern that the system is dewatering the aquifer. The City of Phoenix is copied onassociated OU1 reports. The City has not received any citizen complaints regarding OU1.Ms. O’Regan stated that she was unaware of any new regulations/guidance that wouldaffect OU1. She did state, however, that vapor intrusion is a top issue for the City, alongwith OU3 and the declining water levels. In regards to vapor intrusion, there aren’t anystandards and the guidance is controversial and she would appreciate some appropriateguidance on how to handle this issue. She stated that the TI Waiver is also a big concernfor the City. Ms. O’Regan recommended that Councilman Mattox, Cynthia Parker, andDonn Stoltzfus be interviewed.

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George Ring, Robert Frank and Phil Burke, Hydrogeologists with CH2M Hill.Mssrs. Ring, Frank and Burke were retained by and represented Troy Meyer ofHoneywell. Excerpts of their responses to the interview are as follows. The main issueraised during the interview process concerned the effectiveness of OU1 in capturing thecontamination in the bedrock and that data has not been provided to support full capture.The monitoring well network to show hydraulic capture is not adequate. The effect ofOU1 has kept high levels of VOC contamination from migrating to the HoneywellFacility and OU2, and the effectiveness has a great impact on the future operation andlongevity of OU2. Another key concern is the adequate characterization on the north sideof the plume. They also stated that at one time Honeywell was kept fairly well informedon the activities at OU1, however, Honeywell hasn’t been as well informed on documentsubmittals from Freescale over the last few years. Honeywell is concerned that issuesraised in the last 5 year review have not been addressed and that similar issues have beendiscussed during this interview. On June 12, 2006, ADEQ received a supplement to theinterview which offers some additional details regarding Honeywell’s concerns of theeffectiveness of the OU1 system (Appendix G).

Larry Rodriquez, Supervisor, GPI. Mr. Rodriquez provided a written response to theinterview questions. Excerpts of his responses to the interview are as follows. OU1 wasdesigned to remove VOC contaminants from the upper status of the water table bycreating a cone of depression with extraction wells along the crosscut canal and 46thStreet. Since implementation, 3 wells have been taken off-line which suggest to him thatthe contaminant levels have dropped. The reports show a separation of plumes. Mr.Rodriquez is responsible for providing assistance to O&M personnel, set up of dailyroutines for equipment maintenance and acts as a liaison to other parties involved in theproject. Significant changes to OU1 have included the temporary setup of the Vapor-Pac10 and the addition of hexametaphosphate to the air stripper to control scaling. O&Mdifficulties have included the declining water table, hairline cracks found in the vaporphase carbon vessel, and scale buildup. Mr. Rodriquez recommended that extraction inthe courtyard area should be increased and that the treated water should be re-injected.Mr. Rodriquez also made a recommendation regarding computer set-up and overallcommunication technology.

Leo Wilson, Operator, GPI. Mr. Wilson provided a written response to the interviewquestions. Excerpts of his responses to the interview are as follows. OU1 was designed toobtain and maintain a capture zone to allow the pump and treat of the well water. Mr.Wilson stated that the remedy is doing what it was designed for. Mr. Wilson operatesOU1 during the week and is on call as well. Mr. Wilson stated that general maintenanceactivities (i.e., pump replacement, floor coating, etc.) have occurred over the last 5 years.Significant changes to OU1 have included installing the Vapor Pac 10 instead of thevapor phase units and the addition of the hexametaphosphate. Mr. Wilson also stated thatthe drought and the failure of the vapor phase units were some of the difficulties thatwere encountered. Optimization of OU1 has included changing out pumps and piping tohave a control valve on each series of pumps.

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Donn Stoltzfus, Environmental Program Specialist, City of Phoenix. Mr. Stoltzfus isa representative of the City of Phoenix and is involved in issues surrounding theredevelopment of the site. Excerpts of his responses to the interview are as follows. OU1is a treatment system in the Courtyard Area and an SVE system was implemented in theparking lot to the south. OU1 is a containment remedy. Mr. Stoltzfus stated that he wouldlike to see more investment in the removal of DNAPL at OU1. Mr. Stoltzfus stated thatthere haven’t been any communications from his office regarding OU1 and that there alsohas not been any complaints received on OU1. He is not aware of any communityconcerns regarding OU1. He stated that he feels that he has been kept reasonably wellinformed about the project. He is aware that there are re-development plans for the areaand the City is concerned about groundwater resources in the area. Mr. Stoltzfus statedthat he thought that the appropriate O&M and monitoring have been implemented forOU1.

6.6 Site Inspection

Representatives of ADEQ, LFR, ON Semiconductor, and Freescale conducted a siteinspection of the OU1 Treatment System on June 8 and 9, 2006. The inspection was leadby Kris Paschall, Project Manager for ADEQ, and Robert Forsberg, Project Manager forLFR. Other inspection participants included Michael Nesky and Ned Overs from LFR,David Haag from ADEQ, and Tim Jones from ON Semiconductor. The inspection wassupported by Tom Suriano, Project Manager for Freescale and Larry Rodriguez,Operations Supervisor of GPI, who guided the inspection team around the OU1 systemsand answered questions from the inspection team. The site inspection was performedusing a checklist prepared by LFR. The completed checklist is included in Appendix H.

The site inspection involved the following activities:

• conducting interviews with on-site operators;

• reviewing documents that are maintained off-site and on-site;

• visual inspection of the OU1 Treatment System.

Weather conditions during the inspection were favorable, sunny with high temperatures.No problems were encountered with access to relevant site features inspected. Thetreatment inspection was conducted to provide information regarding the O&M statusand document the conditions of the treatment plant.

Prior to performing the site inspection, LFR reviewed available copies of historicaldesign and engineering documents, record drawings, treated effluent monitoring plan, thePQGWWP, the IGWTP effluent monitoring records/data and air emissions data, carbonchange out records, waste profiling data, and manifests of the spent carbon and recoveredsolvents sent off-site for regeneration and recycling. During the inspection, LFRreviewed the IGWTP records, including: daily/bi-weekly/monthly operating logs,pH/ORP calibration logs, maintenance logs, and other documents to assess operation and

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maintenance compliance. No significant issues with record keeping were discovered andall operation and maintenance activities were being performed in compliance withoriginal and/or modified design specifications.

A review of the air emissions data was conducted as part of the site inspection. Airemissions effluent data indicated that all effluent sample results were less than 3 poundsper day. Between 2001 and 2003, influent and effluent air emissions were analyzed usinga handheld photoionization detector (PID). From August 2003 through current, influentand effluent air emissions were sampled and submitted to an analytical laboratory fortesting. Air samples are collected routinely (typically every two weeks). The air samplesare collected to monitor the removal efficiency of the carbon and to determine when thecarbon needs to be replaced. The carbon is changed out and replaced with fresh carbonwhen it is determined that the carbon efficiency is low.

In general, the OU1 IGWTP remediation system was in fair condition and operatingwithin specified ranges. However, all components of the IGWTP are significantlyweathered and aged and likely nearing the end of their serviceable life, such thatreplacement rather than routine maintenance should be evaluated on a lifecycle basis.

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7.0 TECHNICAL ASSESSMENT

In accordance with the Comprehensive Five Year Review Guidance (Guidance), datedJune 2001, the five-year review should determine if the remedy is protective of humanhealth and the environment and that it satisfies the performance criteria set forth in thedecision documents. In order to assess the protectiveness of the remedy, the technicalassessment should address three questions:

Question A: Is the remedy functioning as intended by the decision documents?

Question B: Are the exposure assumptions, toxicity data, cleanup levels, andRAOs used at the time of the remedy selection still valid?

Question C: Has any other information come to light that could call intoquestion the protectiveness of the remedy?

Pursuant to Guidance, these questions were developed as the framework for organizingand evaluating data and information and ensure that all relevant issues are consideredwhen determining the protectiveness of the remedy.

The following subsections will examine each of these questions in detail.

7.1 Question A: Is the remedy functioning as intended by the decisiondocuments?

The following sections discuss the performance of the OU1 remedy. The technicalassessment included reviewing the following:

• remedial action performance and monitoring results;

• system Operations/O&M;

• costs of the system operations/O&M;

• opportunities for optimization;

• early indicators of potential remedy problems; and

• implementation of institutional controls and other measures.

The relevant decision documents are summarized in Section 3.3.7. Based on thesedocuments, the performance standards for the OU1 interim remedy are:

• soil vapor extraction in identified source areas to remove VOCs in theunsaturated soils to levels agreed upon by ADEQ;

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• establish a zone of capture at the Old Crosscut Canal to hydraulically containgroundwater contamination. The system should also have a beneficial impact ongroundwater quality within bedrock;

• source area (on-site) groundwater extraction to reduce or eliminate contaminantmigration;

• end use of all extracted groundwater at the former Motorola 52nd Street Facility(now ON Semiconductor);

• treatment of extracted groundwater to meet federal, state, and local standards forthe designated end-use.

7.1.1 Remedial Action Performance and Monitoring Results

Soil Remedy

The Courtyard SVE and SWPL AS/SVE systems were not in operation during thisfive-year review period. Freescale submitted a letter requesting closure of the CourtyardSVE on April 30, 1998. ADEQ reviewed Freescale’s request and recommendedpreparing a workplan for collection of soil or soil gas samples. Once the workplan isfinalized, ADEQ will determine an evaluation criteria based on Arizona’s Soil Rule.Arizona’s Soil Rule is in the process of being revised. Once the Soil Rule is promulgated,the CO will be amended to include the new provisions.

On March 21, 2001, Freescale provided a written request for an NFA of the continuedsoil remediation at the SWPL Area. ADEQ determined that the soil cleanup in the SWPLArea was complete in a letter dated November 15, 2002.

No active soil remediation has been conducted in the ATP Area to date. Data collected byFreescale suggests that soil vapor extraction is not needed at the ATP; however, ADEQand Freescale have agreed to conduct a soil investigation pending the revision ofArizona’s Soil Rule.

Groundwater Remedy

The groundwater extraction system consists of 16 on-site and 9 off-site extraction wells.The 16 on-site extraction wells are intended to reduce the high concentrations within thesource areas. The 9 off-site extraction wells provide hydraulic containment west of thesite to approximately the Old Crosscut Canal. There are also a total of 68 monitoringwells within OU1, 27 of which are multiport or Westbay wells.

Extracted groundwater is treated in the IGWTP and transferred to the ON Semiconductorplant for use in their processes providing a beneficial end use for the water. Treatmentplant influent and effluent data are collected on a bi-monthly basis. The effluent resultswere compared to the requirements of the ROD and LOD. Based on the data reviewed,the treated effluent met the requirements of the ROD and LOD.

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In order to effectively assess groundwater contaminant capture, the OU1 interim remedywas evaluated based on a systematic approach developed by EPA using six basic stepsfor systematic capture zone analysis using “converging lines of evidence” and an iterativeapproach (Capture Zone Analyses for Pump-and-Treat System, EPA Training Coursehand-outs, presented to the State of Arizona, May 25, 2005). The following guidancedocuments were used to perform the analysis:

• Methods for Monitoring Pump-and-Treat Performance, U.S. EPA, Office ofResearch and Development, 1994 (EPA 600-R-94-123)

• Elements for Effective Management of Operating Pump and Treat Systems, U.S.EPA, Office of Solid Waste and Emergency Response, 2002 (EPA 542-R-02-009)

The above described EPA six step approach for the OU1 capture zone is summarized inthe following subsections.

7.1.1.1 Step 1: Review Site Data, Site Conceptual Model, and Remedy Objective

The review of site data was summarized in Section 5.4.

Conceptual Site Model

The Site is located in the eastern part of the City of Phoenix. There is a mixture ofresidential, commercial, and industrial land use in the area overlying the site. Releases ofhazardous substances from the former Motorola 52nd Street Semiconductor ProductsPlant impacted soil and groundwater and the releases from multiple sources have createdan extensive groundwater contaminant plume (see Figure 1). Additional potentiallyresponsible parties may have also contributed to the groundwater plume. The primaryCOCs are TCE, TCA, and their reductive daughter products. These contaminants seepedin the subsurface, though the vadose zone, and have mixed into and spread with thegroundwater.

The Site is situated in the western Salt River Valley of the Basin and RangePhysiographic Province characterized by alluvial-filled basins bounded by fault-blockmountain ranges (Reynolds and Bartlett, 2002). OU1 occurs near the eastern basinmargin with outcrops of bedrock a relatively short distance to the east, northeast, andsoutheast. Two primary hydrogeologic units have been identified at OU1: an upperalluvial unit and underlying bedrock. The alluvial unit is further subdivided into severalsubunits elsewhere in the basin, but at OU1 is relatively thin and characteristic of thefiner-grained or “basin fill” alluvium subunit.

Data collected from groundwater monitor wells installed during investigations of the Sitestarting in 1983, indicates that the groundwater table is encountered at depths rangingfrom approximately 40 ft bgs beneath the former Motorola Facility to approximately 75feet bgs at the Old Crosscut Canal. Potentiometric maps developed based on that dataindicate groundwater flow under OU1 is generally to the west-southwest although locally

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it may vary significantly due to areas of groundwater extraction and, in the alluvium, as aresult of bedrock subcrops that intersect the water table and alter or impede groundwaterflow. Groundwater flow in bedrock is thought to occur predominately as fracture flow.

The COCs have been identified in both alluvium and bedrock. TCE concentrations ingroundwater in the alluvial unit generally peak between 1,000 and 3,500 :g/l in thesource area, and in the vicinity of the Old Crosscut Canal. In bedrock, TCEconcentrations in groundwater are greater than 10,000 :g/l in the source area and greaterthan 5,000 :g/l beneath the vicinity of the Old Crosscut Canal. There is a high likelihoodthat DNAPL is present when dissolved-phase concentrations in groundwater in thevicinity of the source exceed 1 to 5 percent of the solubility limit. Source areaconcentrations of TCE indicate the presence of DNAPL and DNAPL has been observedin monitor well MP-03-D.

Remedial Action Objectives

In summary, the remedial action objectives of the OU1 interim remedy regardinggroundwater are:

• establish a zone of capture at the Old Crosscut Canal to hydraulicallycontain groundwater contamination. The system should also have abeneficial impact on groundwater quality within bedrock;

• Source area (on-site) groundwater extraction to reduce or eliminatecontaminant migration.

• End use of all extracted groundwater at the former Motorola 52nd Streetfacility (now On Semiconductor).

• Treatment of extracted groundwater to meet federal, state, and localstandards for the designated end-use.

7.1.1.2 Step 2: Define the Site-specific Target Capture Zone

The site-specific Target Capture Zone (TCZ) is defined as the entire width and depth ofthe OU1 contaminant plume, primarily TCE, in the vicinity of Old Crosscut Canal. Thismeans that the width of the contaminant plume in both the alluvium and bedrock units.

The OU1 remedy was designed to reduce or eliminate contaminant migration ingroundwater under the Courtyard and SWPL Areas and establish a zone of capture at theOld Crosscut Canal to hydraulic contain groundwater contamination. The design includesa total of 25 groundwater extraction wells: four in the Courtyard, twelve in the SWPLArea, and nine at the Old Crosscut Canal. The majority of these 25 groundwaterextraction wells were constructed with screens that extend across the alluvial/bedrockinterface. This screen design allows groundwater to be extracted from alluvium andbedrock. Because the bedrock has a hydraulic conductivity that is typically one or more

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orders of magnitude lower than the alluvium, the majority of extracted water from thewells comes from the alluvium. According to Freescale, extraction of alluvialgroundwater creates an upward vertical gradient in bedrock. Based on this theory,establishing a zone of capture in the alluvium creates a zone of capture in the bedrock.With the exception of the issues regarding capture below, Freescale has shown thatlocally, adequate alluvial capture creates the necessary vertical gradients to provide asupporting line of evidence for capture in bedrock.

7.1.1.3 Step 3: Interpret Water Levels Using Potentiometric Surface Maps and WaterLevel Pairs

Potentiometric Surface Maps and Hydrogeologic Cross Sections

Groundwater levels have been interpreted for the OU1 remedy in GroundwaterMonitoring Reports and Annual Effectiveness Reports. Alluvial water level elevationmaps and water level elevation cross sections have been completed by Freescale for eachfall sampling event. Copies of the maps and cross sections from the Annual EffectivenessReports for 2001, 2002, 2003, 2004, and 2005 operations are included in Appendix C.These figures depict the groundwater elevation contours and zone of capture asinterpreted by Freescale. It should be noted that Freescale uses water levels adjusted forwell efficiency from the extraction wells in each of the elevation maps.

Review of these Annual Effectiveness Reports has consistently identified two primaryissues associated with capture.

EW-18

TCE concentrations in EW-18 began to increase in the late 1990’ s and have beenapproximately 20 :g/L for the last five years. These concentrations are a concern becausethe well is located north of the primary alluvial groundwater contamination migratingaround the north end of the local bedrock ridge. The presence of TCE above the ArizonaAquifer Water Quality Standard (5 :g/L) has not been adequately addressed by theconceptual site model. Additionally, there are no wells in the immediate vicinity to betterdefine the extent of contamination north and west of the well. Also, the well is locatednear the margin of the zone of capture; meaning that potential groundwatercontamination north and west of the well may not be captured by the Old Crosscut Canalextraction wells.

Uncertainty of Vertical Capture

The OU1 system depends on effective alluvial capture for bedrock capture. In theory,extracting groundwater in the alluvium creates a local lower pressure condition at thealluvium/bedrock interface. The result is an induced upward vertical gradient in theunderlying bedrock and thereby capture in bedrock. The theory depends on adequatepumping in the alluvium and saturated conditions at the alluvium/bedrock interface. Thisconcept of bedrock capture has been supported by upward vertical gradients indicated in

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several multiport/Westbay . wells in OU1; however, one of the wells, DM-606, hasconsistently indicated a downward vertical gradient.

Freescale has maintained that the downward vertical gradients are induced by the systemand at depth become upward vertical gradients that are ultimately captured by the OldCross Cut Canal extraction wells. This issue was specifically identified during review ofthe 2003 Annual Effectiveness Report. Freescale responded by referencing a flow netfrom 1992 which indicates that groundwater moving past the deepest DM-606 port (330ft bgs) is within the zone of capture. The following response was provided by ADEQ:

The downward vertical gradient in DM606 may adversely affect deep bedrock capture.Freescale’s response indicates that water moving past the deeper DM606 ports isdeflected upward toward the extraction system citing upward vertical gradient data nearthe extraction system as support. An upward vertical gradient is indicated by the DM603data however; the deepest port in this well is only 245 ft bgs (approximately 938 ft msl).The two lowermost ports of DM606 are deeper at 330 ft and 370 ft bgs (approximately865 ft and 825 ft msl, respectively). The shallower ports of DM603 provide less supportfor capture of groundwater flowing past the deeper DM606 ports. Furthermore, the 1992flow net provided in the Responses illustrates that groundwater moving past the 330 ftport of DM606 is just within the zone of capture.

In summary, additional data are needed to support vertical capture in the vicinity ofDM-606. Freescale’s new multiport groundwater monitor wells should provide additionaldata useful in evaluating vertical capture, but more data is needed in the vicinity ofDM-606.

7.1.1.4 Step 4: Perform Calculations (if appropriate based on Site complexity)

ADEQ’s review of the 2003 Annual Effectiveness Report included a request forFreescale to develop flow nets based on vertically distributed groundwater elevation dataand incorporating changes in aquifer properties between the alluvial aquifer and bedrockaquifer as a means to more closely examine the issue of vertical capture. Freescaleresponded by referencing a flow net from 1992 which indicated that groundwater movingpast the deepest DM-606 port (330 ft bgs) was within the zone of capture. ADEQ’sresponse, provided above, indicated that the flow net illustrated that capture wasminimally demonstrated and additional data were needed to support vertical capture.

Freescale also recently developed a numeric groundwater flow model to analyze captureand longevity of the interim remedy. ADEQ has performed a review of the model anddetermined that several problems exist. ADEQ notes that it is problematic to attempt tomodel fractured bedrock conditions in a porous medium model; however, ADEQ doesnot feel the bedrock conductivity values used in the model are representative of the Siteand may overestimate capture. ADEQ and Freescale are currently working throughactions related to the final feasibility study to address the bedrock conductivity issue.

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7.1.1.5 Step 5: Evaluate Concentration Trends

Groundwater chemistry plots provided by Freescale in the Annual Effectiveness Reportsare presented in Appendix F. The graphs provide supporting evidence for the reduction ofmass in alluvial groundwater monitor wells; however, concentration trends ingroundwater extraction wells and groundwater monitor wells screened in bedrock arecomplex and not easily interpreted.

Several of the groundwater extraction wells, which are typically screened across bothalluvium and bedrock, show increasing concentration trends. Freescale has indicated thatthese trends provide evidence to support that the OU1 system is causing contamination inbedrock to migrate upward, toward the alluvium. Freescale has also indicated that theincreasing trends are a result of an increasing portion of extracted water from bedrockversus alluvium. The overall concentration trend increases because the bedrockconcentrations are higher than the alluvial concentrations. Freescale also indicates thatthe increasing trends in specific wells screened only in bedrock are an indication that theOU1 system is causing contamination in deeper bedrock to migrate upward into shallowbedrock.

While it may be appropriate to consider each of these concepts and the impact on theOU1 system, they provide a limited supporting line of evidence for capture. The data arelimited because alternate interpretations exist, based on the available data. As discussedin the preceding sections, additional data are needed to more fully evaluate this line ofevidence.

It was also noted that groundwater concentrations in the shallow bedrock ports ofDM-125 and DM-601 appear to be increasing. These data indicate that the on-sitegroundwater extraction system may not be reducing or eliminating contaminantmigration from the source area.

7.1.1.6 Step 6: Interpret Actual Capture Based on Steps 1-5, Compare to TargetCapture Zone, and Assess Uncertainties and Data Gaps

ADEQ is concerned that the source area interim remedy is not significantly effective inreducing the levels of contaminants due to the DNAPL in the fractured bedrock. ADEQis concerned that high concentrations of TCE will continue in the source area wells for along period of time.

Based on increasing groundwater concentrations in the shallow bedrock ports of DM-125and DM-601, the on-site groundwater extraction system may not be reducing oreliminating contaminant migration from the source area.

Based on a conservative interpretation of the data, using converging lines of evidence, itappears that capture of the TCZ in bedrock is uncertain.

Concentrations in extraction well DM-313 are currently very close to the MCL for TCE.Concentrations in this well have been increasing slightly over the last three years.

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If concentrations continue to increase and exceed the MCL, this well must be put backinto operation.

Based on a conservative interpretation of the data, using converging lines of evidence, itappears the alluvial portion of the OU1 system may not be meeting the remedy objectivesin the area of EW-18/Old Crosscut Canal. Adequacy of capture in this area is furthercomplicated by the lack of groundwater elevation and quality data in the vicinity ofEW-18.

Alternative interpretations of capture are possible; they are related to alternativeinterpretation of capture in bedrock and bedrock conductivity. Additional data are neededto address the TCZ in alluvium and bedrock.

7.1.2 System Operations/O&M

In general, the OU1 IGWTP remediation system was in fair condition and operatingwithin specified ranges. However, all components of the IGWTP are significantlyweathered and aged and likely nearing the end of their serviceable life, such thatreplacement rather than routine maintenance should be evaluated on a lifecycle basis.

7.1.3 Costs of System Operations/O&M

From 2001 to 2002, O&M costs for the IGWTP increased from approximately $577,703to $1,206,523. Freescale stated that the increase was related to the ONSemiconductor-Motorola separation and represented the accrual of land and utility costsnot previously captured since the remedy was integrated into the manufacturingoperations at the former Motorola 52nd Street Facility. From 2002 to 2005, the O&Mcosts were generally consistent. Table 2 provides the annual O&M costs from 2001 to2005. These costs do not include other response costs that were incurred for OU1 (e.g.,agency oversight).

7.1.4 Monitoring Activities

Capture and containment can only be confirmed with an adequate monitor well networkthat provides both groundwater level data to demonstrate hydraulic capture andgroundwater quality data to demonstrate overall reduction of mass within and outside thecapture zone(s). A review of the existing monitor well network indicated several areaswhere lack of data hinders the evaluation of the effectiveness of the remedy. Additionalalluvial and bedrock monitor wells are needed in the vicinity of EW-18 to address theextent of contamination and evaluate capture of the TCZ. Additional bedrock monitorwells are also needed to address the uncertainty of capture in bedrock both downgradientof the on-site system and at the Old Crosscut Canal system. Freescale has installed onemultiport monitor well downgradient of the Old Crosscut Canal; however, additionalmonitor wells are needed to support the assessment of capture in bedrock.

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7.1.5 Opportunities for Optimization

A review of the IGWTP treatment system indicated that there may be an opportunity toincrease the air stripper’s efficiency by changing the type, size and configuration ofpacking within the air stripper columns. Such a change likely has the most potential toprovide significant increases in air stripper treatment operational efficiencies.

Moreover, a lifecycle cost analysis should be performed to determine if optimization ofthe existing system versus replacing the existing treatment and/or extraction system ispreferable. New extraction well and/or extraction pump designs and specifications shouldbe evaluated against long-term groundwater capture and remedial objectives.

7.1.6 Early Indicators or Potential Remedy Problems

Potential Capture Problems

Extraction primarily from the alluvial aquifer is credited for hydraulic capture atsubstantial depth in the bedrock aquifer. As yield from the alluvial aquifer decreases,resulting changes in the predicted vertical capture needs to be addressed. Freescale hasindicated that adequate capture in bedrock is readily maintained by the current systemdespite current or future declining groundwater levels.

As previously stated by ADEQ in Effectiveness Report comments and during meetingswith Freescale, declining groundwater elevations at the Site due to both regional declineand OU1 pumping, potentially aggravate the existing uncertainty of bedrock capture. Thepotential finite capacity of the system to capture bedrock contamination as the regionalaquifer continues to decline represents a potential remedy problem.

In response to the issues raised by ADEQ regarding the potential remedy problem,Freescale developed a groundwater flow model to analyze future system effectivenessunder continuing groundwater decline. The results of the model were included in theGroundwater Remedial Alternative Analysis, Motorola 52nd Street OU1, Phoenix,Arizona Report prepared by GeoTrans, Inc., dated September 30, 2005 (GRAA). Reviewof the Report indicates that Freescale believes the groundwater modeling effortadequately demonstrates that continued decline of regional groundwater levels will notresult in a failure of the Old Crosscut Canal system to capture the TCZ. The GRAA alsorecommends increased bedrock extraction at the Courtyard to optimize reduction of massand increase bedrock capture.

The model and GRAA are currently under review; however, preliminary findingsindicate several issues with the model and the Report exist. ADEQ and Freescale met todiscuss ADEQ’s initial review. ADEQ is concerned that a fundamental difference in theconceptual site models of ADEQ and Freescale exists. The difference is centered on thenature of bedrock conductivity and contamination. Freescale indicates that bedrockconductivity is very low (i.e., less than 0.1 ft/day and likely as low as 0.025 to 0.0025ft/day) and that concentrations in bedrock can only be minimally impacted by

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groundwater extraction. ADEQ believes that site data indicate that the bedrock is moreconductive and that bedrock concentrations have been significantly impacted and may bemore readily impacted by increased bedrock extraction. ADEQ feels that the bedrockhydraulic conductivity data gap must be addressed to effectively evaluate futureremediation of OU1.

ADEQ and Freescale agreed that a pilot test is needed to develop a better understandingof bedrock conductivity. Freescale is currently developing a workplan to address this datagap.

System Operations Problems

Downsizing and frequent cycling of groundwater extraction pumps due to lower thananticipated water production rates is an early indicator of either improper wellconstruction or declining groundwater elevations (e.g., drought), or both, which couldresult in failure of the remedy to perform adequate capture.

7.1.7 Implementation of Institutional Controls and Other Measures

Institutional controls have been implemented by ADEQ regarding access to contaminatedgroundwater. Since WQARF was revised in 1997, ADEQ and ADWR have developed aprocedure whereby ADWR notifies ADEQ when a NOI to Drill a Monitor Well withinthe Motorola 52nd Street Superfund Site has been filed. ADEQ can then notify theproperty owner of the risk involved with using the groundwater.

7.2 Question B: Are the exposure assumptions, toxicity data, cleanup levels, andRAOs used at the time of the remedy selection still valid?

7.2.1 Changes in Standards and To Be Considered

No ARARs were established in the OU1 ROD and LOD. However, there were standardsestablished for work on the Site in the CO. OU1 is currently in compliance with therequirements of the CO (Table 4 and 5). No chemical-specific soil or groundwaterclean-up levels were established in the ROD and LOD. However, new ARARs and TBCswill be determined for the final remedy as described in the forthcoming Remedial ActionObjectives Report for OU1. The purpose of the RAO Report is to establish remedialobjectives for the OU1 Area that are based on current and reasonably foreseeable uses ofthe groundwater and property. The remedial objectives will be based on the ARARs andTBCs developed for the Site. Chemical-specific ARARs that should be considered for thefinal remedy are discussed below.

Standards for soil will likely include Arizona Soil Remediation Levels (SRLs), ArizonaGroundwater Protection Limits (GPLs), Arizona Health Based Guidance Levels(HBGLs), or EPA Preliminary Remediation Goals (PRGs). The SRLs are statewideclean-up levels and apply to all environmental regulatory programs administered byADEQ. Because COCs in the vadose zone have leached into and impacted the

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groundwater, it is possible that calculated GPLs would be more stringent than the SRLs.If ADEQ remediation standards are not established for particular compounds, the use ofHBGLs would be relevant and appropriate. If HBGLs are not available, EPA Region IXPRGs for industrial soils would then be relevant and appropriate.

Standards for groundwater will likely include Arizona AWQSs, EPA MCLs, and PRGs.The AWQSs provide numeric standards for drinking water protected use, which areapplicable to all groundwater remediation activities conducted in the State of Arizona. IfAWQSs standards are not established for particular compounds, the use of MCLs wouldbe relevant and appropriate. If MCLs are not established for particular compounds thanthe use of HBGLs would be relevant and appropriate. If HBGLs are not available, EPARegion IX PRGs would then be relevant and appropriate.

7.2.2 Changes in Exposure Pathways, Toxicity, and Other Contaminant Characteristics

Land use at the Site has remained relatively the same and no new human health orecological routes of exposure have been identified.

Since the 1992 health evaluation, there have been a number of changes to the toxicityvalues for certain contaminants of concern at the Site (Table 6). Revisions to the toxicityvalues for 1,1-DCE and vinyl chloride indicate a lower risk from exposure to thesechemicals that previously considered. On the other hand, evaluation of the toxicity valuesfor PCE and TCE is ongoing and may indicate higher risks from exposure thanpreviously considered.

The greatest uncertainty with toxicological changes for the Site is associated with TCE.In August 2001, U.S. EPA’s Office of Research and Development (ORD) released thedraft Trichloroethylene Health Risk Assessment: Synthesis and Characterization (TCEHealth Risk Assessment) for external peer review. The draft TCE Health RiskAssessment takes into account recent scientific studies of the health risks posed by TCE.According to the draft TCE Health Risk Assessment, for those who have increasedsusceptibility and/or higher background exposures, TCE could pose a higher risk throughinhalation than previously considered. The draft TCE Health Risk Assessment isavailable on-line at: http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=23249.

The Science Advisory Board, a team of outside experts convened by U.S. EPA, reviewedthe draft TCE Health Risk Assessment in 2002. The Science Advisory Board’s review ofthe draft TCE Health Risk Assessment is available at: http://www.epa.gov/sab/pdf/ehc03002.pdf.

In July 2006, the National Academy of Sciences completed additional peer review ofscientific issues that were the basis for the draft TCE Health Risk Assessment. Inresponse to this review, U.S. EPA will revise the draft TCE Health Risk Assessment.

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Consequently, review of the toxicity value for TCE may continue for a number of years.This issue will need to be updated in subsequent five-year reviews.

In addition, an HBGL and PRG have been established for 1,4-dioxane. This contaminanthas been detected at the Site at elevated concentrations and should be addressed in thefinal remedy.

7.2.3 Changes in Risk Assessment Methods

The1992 risk assessment methodology was based on EPA Risk Assessment Guidance forSuperfund, Volume I, Human Health Evaluation Manual: Part A (EPA, 1989). Currentmethodology for risk assessment has not changed, however, the air model used toestimate indoor risks has changed and it would be prudent to model current risks basedon this newer model (EPA Draft Guidance for Evaluating the Vapor Intrusion to IndoorAir Pathway From Groundwater and Soils, November 2002) and updated toxicity values.ADEQ is currently evaluating the methodology for assessing the indoor air risks and willimplement the methodology once the guidance is finalized, or other methodology can beagreed upon by ADEQ and EPA. In the meantime, ADEQ requested Freescale to conducta study in 2005 using soil gas data collected during a 1995 soil gas investigation at OU1.The results of this study are discussed in Section 3.3.11.

7.2.4 Progress Towards Meeting RAOs

The RAOs provided in the LOD, ROD were selected to set goals for an interimgroundwater remedy designed to contain and reduce groundwater contamination. Nochemical-specific soil or groundwater clean-up levels were established in the ROD andLOD. Freescale is currently conducting a Groundwater Remedial Alternatives Analysisas an addendum to the 1987 feasibility study (FS) to support the selection of a finalremedy. Therefore, the current set of RAOs is being re-evaluated to set cleanup standardsfor a final remedy.

7.3 Question C: Has any other information come to light that could call intoquestion the protectiveness of the remedy?

ADEQ is aware that there may be additional upgradient sources to groundwatercontamination. ADEQ is currently conducting potentially responsible party (PRP)searches to identify these potential sources and will evaluate whether these sourcesimpact the remedy.

As groundwater elevations decline at the Site due to both regional decline and OU1pumping, the area of the alluvium/bedrock interface is increased, potentially aggravatingthe existing uncertainty of bedrock capture. The potential finite capacity of the system tocapture bedrock contamination as the regional aquifer continues to decline represents apotential remedy problem.

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7.4 Summary of Technical Assessment

According to the data reviewed, the site inspection, and the interviews, ADEQ hasidentified several concerns that questions the effectiveness of the remedy. Capture inbedrock and to the north of the Old Crosscut Canal (near EW-18) is questionable. Inaddition, concentrations in groundwater downgradient of the source area indicate that theonsite groundwater extraction system may not be reducing or eliminating contaminantmigration from the source area. Continuing decline of groundwater elevations may callinto question the future effectiveness of the groundwater treatment system.

Changes to toxicity factors of certain COCs have occurred and should be evaluated. Inaddition, new methodology to evaluate indoor air risks is being developed. While nochemical-specific soil or groundwater clean-up levels were established in the ROD andLOD, ADEQ is currently developing chemical-specific RAOs for the final remedy.

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8.0 ISSUES

The following issues discovered during the five-year review are discussed below and areincluded in Table 7.

8.1 Groundwater Issues

Several groundwater issues were identified during the technical assessment of the OU1interim remedy. These issues are primarily associated with groundwater capture andsource removal. The following is a list of the issues.

8.1.1 Capture Issues

1) Capture and containment can only be confirmed with an adequate monitor wellnetwork that provides both groundwater level data to demonstrate hydrauliccapture and groundwater quality data to demonstrate overall reduction of masswithin and outside the capture zone(s). Additional groundwater elevation andquality data are needed to adequately evaluate the OU1 system. The monitoringnetwork needs to be evaluated and updated based on current site conditions andissues.

2) Based on a conservative interpretation of the data, using converging lines ofevidence, it appears that capture of the TCZ in bedrock is uncertain. Additionalbedrock monitor wells are needed to address the uncertainty of capture in bedrockboth downgradient of the on-site system (DM-125, DM-601, and DM-606 areas)and the OCC system between OCC and DM-118, DM-119, DM-120, DM-122,DM-123, DM-502, and DM503 area). Freescale has installed one multiportbedrock well; however, an increased monitor well network is needed to supportthe assessment of capture in bedrock.

3) Based on a conservative interpretation of the data, using converging lines ofevidence, it appears the TCZ in the vicinity of EW-18 is questionable. Additionalalluvial and bedrock monitor wells are needed in the vicinity of EW-18 to addressthe extent of contamination and evaluate capture of the TCZ.

4) Extraction primarily from the alluvial aquifer is credited for hydraulic capture atsubstantial depth in the bedrock aquifer. ADEQ is concerned that declininggroundwater elevations at the site due to both regional decline and OU1 pumpingwill reduce the effectiveness of bedrock capture. As yield from the alluvialaquifer decreases, resulting changes in the predicted vertical capture needs to beaddressed. The potential finite capacity of the system to capture bedrockcontamination as the regional aquifer continues to decline represents a potentialremedy problem.

5) Concentrations in extraction well DM-313 are currently very close to the MCLfor TCE. Concentrations in this well have been increasing slightly over the last

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three years. If concentrations continue to increase and exceed the MCL, this wellmust be put back into operation.

8.1.2 Source Removal Issues

6) ADEQ is concerned that the source area interim remedy is not significantlyeffective in reducing the levels of contaminants due to the DNAPL in thefractured bedrock. ADEQ is concerned that high concentrations of TCE willcontinue in the source area wells for a long period of time.

7) Groundwater concentrations in the shallow bedrock ports of DM-125 andDM-601 appear to be increasing. These data indicate that the onsite groundwaterextraction system may not be reducing or eliminating contaminant migration fromthe source area.

8.2 Soil Issues

The following issues regarding soils were discovered during the five-year review.

8) Confirmatory soil sampling should be conducted at the Courtyard to obtainclosure. Soil sampling should be conducted once the Arizona Soil Rule andguidance has been finalized.

9) The CO required that an SVE system be installed at the ATP. No active soilremediation has been conducted in the ATP area to date. Soil sampling should beconducted at the ATP to obtain closure once the Arizona Soil Rule has beenfinalized.

8.3 Health Assessment Issues

The following issues were discovered during the five-year review.

10) Changes to the toxicity levels for certain contaminants have occurred since thelast five-year review.

11) New methodology is being developed for indoor air risk evaluation. Once themethodology is finalized or EPA and ADEQ can agree to the process forevaluating the pathway, an indoor air risk evaluation should be performed for theOU1 Area.

12) The Baseline Risk Assessment and Health Assessments recommended to sampleMr. Morgan's well. Access may be an issue for sampling this well. A plan shouldbe developed regarding this well.

13) There is a potential for unregistered, private wells to exist in the OU1 Area.

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8.4 O&M Issues

The following O&M issues were identified during the five-year review.

14) The secondary containment system’s protective coatings showed signs ofweathering (e.g., cracked, peeling, lifting).

15) All PVC piping, valves, and other appurtenances showed signs of ultraviolet(UV) light weathering (e.g., brittle appearance).

16) The stainless steel steam pressure tanks were stress corroded and cracked (this isone of the reasons the steam regeneration is no longer used).

17) Most steel (non-stainless steel) appurtenances (e.g., vacuum releasevalves/breakers, manual ball valves, etc.) showed signs of rusting and/orcorrosion.

8.5 General Issues

The following general issues were identified during the five-year review.

18) The COCs should be identified for the final remedy.

19) Air emissions and influent/effluent analytical data are an important tool forevaluating the effectiveness of the treatment system and should be reported in theannual Effectiveness Reports.

20) Additional upgradient sources to groundwater contamination may exist.

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9.0 FOLLOW-UP ACTIONS AND RECOMMENDATIONS

Based on the issues identified during the five-year review process, the followingcorrective actions should be taken. Table 8 provides a summary of the follow-up actionsand recommendations listed below along with the responsible party, oversight agency,and schedule for completion.

9.1 Follow-up Actions

9.1.1 Groundwater Follow-up Actions

The following follow-up actions regarding the groundwater issues at the OU1 area shouldaddressed.

9.1.1.1 Groundwater Capture

1, 2, 3) A work plan should be prepared and submitted to ADEQ to address the OU1 data gaps identified in Section 8.1.1. The work plan should include a summary of the current conceptual site model, a review of the existing OU1 groundwater monitoring well network and other available data, identify the data gaps, and propose the work necessary to fill the data gaps.

4) A work plan should be prepared and submitted to ADEQ to address the bedrockhydraulic conductivity and extraction issues. The work plan should include theinstallation of a deep bedrock extraction and monitor wells such that a bedrockextraction pilot study may be completed to evaluate bedrock hydraulicconductivity. The results of the study should be incorporated into the feasibilitystudy for the final remedy.

5) Freescale should prepare a plan to monitor the concentrations in DM-313. If theseconcentrations continue to increase and exceed the MCL, the well should be putback into operation.

9.1.1.2 Source Removal

6) Freescale submitted a Groundwater Remedial Alternatives Analysis report inSeptember 2005 followed by an Addendum to the Groundwater RemedialAlternatives Analysis report in December 2005 evaluating treatment technologiesfor DNAPL. The report is currently under review by ADEQ.

7) Freescale should prepare a plan to evaluate the effectiveness of the source areatreatment system.

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9.1.2 Soil Follow-up Actions

The following follow-up actions regarding the soil issues at the OU1 area shouldaddressed.

8) Freescale should develop a workplan to evaluate the vadose zone at the Courtyardarea. The work plan should include evaluation criteria for clean-up. ADEQ willprovide Freescale with the evaluation criteria once the Soil Rule is finalized.

9) A work plan should also be developed for obtaining closure at the ATP. Theclosure criteria will be established once the Soil Rule is finalized and should beincluded in the work plan.

9.1.3 Health Assessment Follow-up Actions

The following follow-up actions regarding the health assessment issues at the OU1 areashould addressed.

10) A review of the toxicity values for COCs at the Site should be conducted beforethe final remedy is selected.

11) Freescale has previously prepared a work plan to address the vapor intrusion toindoor air pathway. New methodology is being developed for indoor air riskevaluation. Once the methodology is finalized or EPA and ADEQ can agree to theprocess for evaluating the pathway, an indoor air risk evaluation should beperformed for the OU1 Area. The work plan should be updated to meet theserequirements.

12) ADEQ and Freescale should develop a plan to collect groundwater samples fromMr. Morgan’s well and take further actions if necessary.

13) ADEQ issues a fact sheet every other year to all the addresses listed within theMotorola 52nd Street Superfund Site. ADEQ will include a note in the next factsheet requesting owners to notify ADEQ of any private well.

9.1.4 O&M Follow-up Actions

The following follow-up actions regarding the O&M issues at the OU1 area shouldaddressed.

14) The secondary containment system’s protective coatings should be repaired.

15) The PVC piping, valves, and other appurtenances that showed signs of weatheringshould be replaced.

16) The stainless steel steam pressure tanks should be replaced if they are broughtback into use.

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17) Steel appurtenances that showed signs of rusting and/or corrosion should bereplaced.

9.1.5 General Follow-up Actions

The following follow-up actions regarding the general issues at the OU1 area shouldaddressed.

18) ADEQ and Freescale should establish a list of COCs for the Site. Once the list hasbeen established, Freescale should conduct a sampling round to evaluate the COClist for the RAOs for the final remedy.

19) Freescale needs to include the air emission and groundwater influent/effluentanalytical data in the annual Effectiveness Reports.

20) ADEQ will conduct a PRP search for upgradient sources and will evaluatewhether these sources will impact the remedy.

9.2 Parties Responsible for Implementation

Freescale, as identified in the supporting decision documents, is responsible for therecommended actions.

9.3 Agencies with Oversight Authority

Pursuant to the supporting decision documents, ADEQ is the current agency withoversight authority.

9.4 Schedule for Completion

Because the OU1 interim remedy issues identified above are current and ongoing, therecommended actions under Section 9.1 should be conducted as soon as practical. Table8 outlines the expected completion date.

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10.0 PROTECTIVENESS STATEMENT

A protectiveness determination of the OU1 interim remedy cannot be made at this timeuntil further information is obtained. The necessary follow-up actions andrecommendations identified in this Report are needed to evaluate protectiveness. Theactions will require the efforts of Freescale and ADEQ to be completed. It is expectedthat these actions will take approximately 1 year to complete at which time aprotectiveness determination will be made.

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11.0 NEXT REVIEW

The next review for the Site is required within five years of EPA’s signature of thisreview. It is anticipated that the next review will be completed by the end of September2011.

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TABLES

Table 1 - Chronology of Events at the OU1 AreaMotorola 52nd Street Superfund Site

Phoenix, Arizona

Date Event1956 Manufacturing Operations commenced at the Motorola 52nd Street facility.

1963 to 1974 A dry well located in the Courtyard area was used for solvent disposal.

1974 to 1976 Southwest Parking Lot (SWPL) area was used for waste chemical storage.

November 1982 Freescale discovered a discrepancy in the inventory for 1,1,1-Trichloroethane (TCA) in a 5,000 gallon underground storage tank (UST).

January 1983 Freescale notified Arizona Department of Health Services (ADHS) of leaking TCA underground tank.

February 1983 Remedial Investigation (RI) initiated.

February through September 1983 Installed 23 on-site, 6 off site, and 2 piezometers. Also identifies provate wells for sampling.

December 1983 Preliminary Investigation Report for 52nd Street facility was submitted to ADEQ by Freescale.

October 1984 A workplan and a quality assurance program plan (QAPP) for the implementation of the RI/FS were issued.

November 1984 Initial soil gas investigation was conducted at the Site.

December 1984 through August 1986 Installation of wells for the RI/FS to supplement wells installed as part of the Preliminary Investigation.

February/March 1985 Soil gas investigation indicated tetrachloroethene (PCE) existed at elevated concentrations between Buildings A-D and A-A, and in the southwest corner of SWPL.

July/August 1985 Monitor wells DM-201 and others installed and aquifer test conducted.

October 1985 through February 1986 Source verification investigations (Stage 1) were conducted.

August 8, 1986 The results of preliminary screening of remedial action technologies and/or alternatives were submitted to ADEQ as a draft report.

September 1986 through October 1986

A well survey was conducted to identify existing monitor wells, public wells, and private wells in an area downgradient from the Site.

September 4, 1986 A work plan to implement the groundwater Pilot Treatment plant (PTP) was issued.

September 15, 1986 The PTP operations were initiated.

June 1987 Draft results of the remedial investigation/feasibility study (RI/FS) study were submitted to ADEQ.

June 1988 Draft Remedial Action Plan (RAP) for OU1 was submitted to ADEQ.

September 1988 EPA issued a Record of Decision (ROD) for OU1 and ADEQ issued a Letter of Determination (LOD) for OU1.

January 1989 Additional soil gas samples were collected within the SWPL area.

January 17-18, 1989 A supplementary soil gas investigation was performed in the Courtyard area to further assess the potential sources identified during previous investigations.

June 20, 1989 Freescale entered into a Consent Order (CO) with ADEQ to implement a groundwater and soil remedy for OU1.

July 26, 1989 Motorola 52nd Street Consent Order was lodged with the Arizona Superior Court.

October 1989 The site was placed on the USEPA CERCLA National Priorities List (NPL).

1990 A sump in the southwest corner of Building A-D was identified as another potential source of contamination in the SWPL area.

August 1990 Additional wells were added to the Pilot Treatment System.

January 4, 1991 A hydrologic report supporting the application for a poor quality groundwater withdrawal permit (PQGWWP) for the OU1 extraction wells was submitted to Arizona Department of Water Resources (ADWR).

February 1991 SWPL investigation was initiated.

March 1991 A soil gas investigation was conducted within the SWPL area.

March 1991 100% completed design drawings for the Integrated Groundwater Treatment Plant (IGWTP) was submitted to ADEQ.

May 8, 1991 ADWR issued a Poor Quality Groundwater Withdrawal Permit (PQGWWP) #590530577 for the OU1 groundwater extraction program.

June 28, 1991 Pumping activities were initiated in SWPL area.

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Table 1 - Chronology of Events at the OU1 AreaMotorola 52nd Street Superfund Site

Phoenix, Arizona

Date EventOctober 1991 through November 1991 Additional soil gas investigation was conducted within the SWPL area.

Januray through February 1992 Drilling of SWPL monitor and extraction wells and soil gas investigation at the SWPL area.

February 19, 1992 Final Remedy RI report for OU1 was completed and submitted by Freescale to ADEQ.

May 1992 A baseline report prior to the startup of the IGWTP was submitted to ADEQ. This baseline report would be used to compare the effectiveness of OU1.

May 1992 The SWPL remedy was expanded.

May 7, 1992 The installation of the Courtyard Soil Vapor Extraction System (Courtyard SVE) system was completed.

May 8-13, 1992 Baseline data for the Courtyard SVE system was collected.

June 3, 1992 The Courtyard SVE system was initially started up and subsequently shut down for process modifications.

July 1992 Permanent treatment system (IGWTP) for OU1 became operational.

September 11, 1992 A final draft SWPL RI Work Plan was submitted to ADEQ.

September 21, 1992 Courtyard SVE pilot program began operation.

September 23, 1992 A draft In-Situ Air Sparging/SVE System Field Test (Pilot Test) Plan was submitted to ADEQ.

February 11, 1993 Air sparging/soil vapor extraction (AS/SVE) pilot program began operation in two locations within the SWPL area; the parking lot and Building A-D. Phase I SVE within the parking lot area was performed.

February 15, 1993 The Phase 2 SVE test within the Building A-D area was performed in the SWPL area.

February 17, 1993 Sensitivity testing was performed on portions of the CYSVE system operation.

February 19, 1993 The Phase 3 AS test was performed on well AS002 in Building A-D in the SWPL area.

February 20, 1993 The combined AS/SVE Phase 4 test was initiated in SWPL area.

February 25, 1993 SWPL AS/SVE pilot program ended.

March 31, 1993 Courtyard SVE pilot program ended.

April 1993 Progress reporting activities for OU1 operations were implemented.

May 1993 The results of the investigation activities performed at the SWPL area was presented in a draft report.

May 1993 The first effectiveness report for OU1 1992 operations was submitted to ADEQ.

June 9, 1993 Draft SWPL RI report submitted to ADEQ.

October 1993 Interim Remedy Feasibility Study Report submitted to ADEQ.

June to December 1993 OU1 permanent system was suspended due to a vinyl chloride air emission problem.

December 10, 1993 Supplement Interim Remedy FS Report submitted to ADEQ.

December 28, 1993 OU1 was put back into continuous operation.

1994 Freescale initiated a program of periodic recovery of dense non-aqueous phase liquid (DNAPL).

February 18, 1994 A report evaluating the bedrock investigation was submitted to ADEQ.

September 1994 Freescale submitted the 1993 OU1 Effectiveness Report to ADEQ.

October 14, 1994 Addendum to SWPL RI report was submitted to ADEQ.

December 1994 A report summarizing the results of the Courtyard SVE pilot program was submitted to ADEQ.

December 1, 1994 A groundwater monitoring plan for OU1 was submitted to ADEQ.

April 21, 1995 AS/SVE Pilot Program for SWPL was submitted to ADEQ.

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Table 1 - Chronology of Events at the OU1 AreaMotorola 52nd Street Superfund Site

Phoenix, Arizona

Date EventApril 21, 1995 SWPL Remediation Design Report was submitted to ADEQ.

April 25, 1995 Design report, plans, and specifications detailing SVE/AS for SWPL were submitted to ADEQ.

April 28, 1995 Freescale submitted the 1994 OU1 Effectiveness Report to ADEQ.

June 1, 1995 ADEQ approved the SVE/AS design plans for SWPL.

September 1995 Five-Year Review report prepared by ADEQ was finalized.

November 16, 1995 EPA accepted and approved the five year review report.

December 4, 1995 Multi-depth soil gas investigation was performed within the Courtyard area.

February 1996 Final construction specification of the installation of the AS/SVE system at the SWPL Building A-D was submitted to ADEQ.

March 1, 1996 Freescale submitted the 1995 OU1 Effectiveness Report to ADEQ.

March 15, 1996 Freescale submits Soil Gas Survey report to ADEQ.

March 29, 1996 SWPL Remediation Operation Plan was submitted to ADEQ.

March 31, 1996 Freescale confirmed that air emission controls that were changed in 1993 are final.

November 1996 SWPL AS/SVE operations began.

March 1, 1997 Freescale submitted the 1996 OU1 Effectiveness Report to ADEQ.

April 1997 The AS/SVE system at SWPL ended.

April 28, 1997 A report on the evaluation of the Courtyard SVE system was submitted to ADEQ.

December 1997 Freescale submitted an updated monitoring plan to ADEQ for review and comments.

December 17, 1997 ADEQ approved the updated monitoring plan subject to minor modifications.

January 1998 Final updated monitoring plan was submitted by Freescale to ADEQ.

January 5, 1998

Freescale submitted a Request for Modification on the PQGWWP to eliminate chloroform, 1,2-DCE, and carbon tetrachloride from the key parameters list, reduce the sampling for VOCs in extraction wells on an annual basis, include the 12 extraction wells in the SWPL area to the modified monitoring program, and reduce the reporting activity on a semi-annual basis. Request was approved by ADWR.

March 31, 1998 Freescale submitted the 1997 OU1 Effectiveness Report to ADEQ.

April 30, 1998 Freescale submitted a no further action request for the Courtyard SVE system.

December 22, 1998 A report on the evaluation of the SWPL SVE system was submitted to ADEQ.

1999Motorola’s Communications, Power, and Signal Group was split off to become ON Semiconductor. Motorola remains responsible for the remediation effort related to its former operations at the 52nd Street facility.

March 31, 1999 Freescale submitted the 1998 OU1 Effectiveness Report to ADEQ.

March 1, 2000 Freescale submitted the 1999 OU1 Effectiveness Report to ADEQ.

August 2000 An updated O&M Manual for the IGWTP was submitted to ADEQ.

January 31, 2001 Freescale submitted Semi-Annual Progress Report 2001-2 PQGWWP Report July through December 2001 to ADWR.

March 2001 Freescale submitted the 2000 OU1 Effectiveness Report to ADEQ.

March 21, 2001 Freescale submitted a no further action request for the SWPL SVE system.

September 2001 Second Five-Year Review report was completed by ADEQ

2002 In response to the Second Five-Year Review, Freescale conducted studies and evaluated the OU1 groundwater treatment remedy.

January 31, 2002 Freescale submitted Semi-Annual Progress Report 2001-2 PQGWWP Report July through December 2001 to ADWR.

Page 3 of 4

Table 1 - Chronology of Events at the OU1 AreaMotorola 52nd Street Superfund Site

Phoenix, Arizona

Date EventMarch 2002 Freescale submitted the 2001 OU1 Effectiveness Report to ADEQ.

July 31, 2002 Freescale submitted Semi-Annual Progress Report 2002-1 PQGWWP Report January through June 2002 to ADWR.

November 15, 2002 ADEQ determined that the soil cleanup in the SWPL area was complete.

January 31, 2003 Freescale submitted Semi-Annual Progress Report 2002-2 PQGWWP Report July through December 2002 to ADWR.

March 2003 Freescale submitted the 2002 OU1 Effectiveness Report to ADEQ.

April 1, 2003 Freescale shut down the OU1 Treatment System after discovering cracks in the carbon vessels that serve as air emission controls.

July 31, 2003 Freescale submitted an OU1 Evaluation – Shutdown and Monitoring report evaluating the impact on groundwater flow and contaminant migration as a result of the recent shutdown of the OU1 Treatment System.

July 31, 2003 Freescale submitted Semi-Annual Progress Report 2003-1 PQGWWP Report January through June 2003 to ADWR.

August 4, 2003 OU1 Treatment System was restarted after Freescale replaced the carbon vessels.

September 17, 2003 Freescale submitted a Work Plan for a Soil Vapor Intrusion Risk Assessment.

October 20, 2003 Freescale submitted a Letter of Intent to conduct a Feasibility Study for the OU1 area.

January 31, 2004 Freescale submitted Semi-Annual Progress Report 2003-2 PQGWWP Report July through December 2003 to ADWR.

March 2004 Freescale submitted the 2003 OU1 Effectiveness Report to ADEQ.

April 2004 Motorola spun off its semiconductor sector into a new company, Freescale Semiconductor, which is a wholly owned subsidiary of Motorola Inc.

April 12, 2004 Freescale submitted a revised QAPP for the OU1 area to ADEQ.

July 31, 2004 Freescale submitted Semi-Annual Progress Report 2004-1 PQGWWP Report January through June 2004 to ADWR.

September 2004 Freescale submitted a revised Work Plan for a Soil Vapor Intrusion Risk Assessment.

September 7, 2004 Freescale submitted a capture analysis as part of a request to turn off extraction well DM-311.

January 27, 2005 Freescale submitted a Work Plan to Install Additional Monitor Wells in the OU1 area.

January 31, 2005 Freescale submitted Semi-Annual Progress Report 2004-2 PQGWWP Report July through December 2004 to ADWR.

March 2005 Freescale submitted the 2004 OU1 Effectiveness Report to ADEQ.

July 31, 2005 Freescale submitted Semi-Annual Progress Report 2005-1 PQGWWP Report January through June 2005 to ADWR.

September 30, 2005 Freescale submitted a Groundwater Remedial Alternatives Analysis report.

December 2005 Freescale submitted an Addendum to the Groundwater Remedial Alternatives Analysis, Evaluation of Technical Impracticability of Groundwater Restoration at the Motorola 52nd Street OU1 report.

March 2006 Freescale submitted the 2005 OU1 Effectiveness Report to ADEQ.

Page 4 of 4

Table 2 - Annual O&M Costs for the OU1 Treatment SystemMotorola 52nd Street Superfund Site

Phoenix, Arizona

Year Total O&M Costs2001 $577,7032002 $1,206,5232003 $1,119,2422004 $1,160,4672005 $1,083,958

Notes: 1. The cost increase starting in 2001 is related to the ON Semiconductor separation and represents the accrual of land and utility costs not previously captured since the remedy was integrated into the manufacturing operations at the 52nd Street facility.

Table 3 - Actions Taken Since the Last Five-Year Review for OU1Motorola 52nd Street Superfund Site

Phoenix, Arizona

Issues from Previous Review Recommendations/Follow-up Actions Party Responsible

Milestone Date Action Taken and Outcome Date of Action

It is ADEQ's opinion that the pump and treat system is not significantly effective in reducing the levels of contaminants due to the DNAPL in fractured bedrock. ADEQ is concerned that high concentrations of TCE will continue in the source area wells for a long time.

ADEQ anticipates that the source area extraction system will approach the limits of effective mass reduction in the source area in the near future. ADEQ believes it would beprudent to begin evaluation of alternative treatment technologies for DNAPL in fractured bedrock. If the source area were effectively reduced, it may greatly reduce the long term operation and monitoring of the current pump and treat system.

Freescale on-going

Freescale prepared a Groundwater Remedial Alternative Analysis, Motorola 52nd Street OU1, Phoenix, Arizona (GRAA) and Addendum to Groundwater Remedial Alternatives Analysis, Evaluation of Technical Impracticability of Groundwater Restoration at the Motorola 52nd Street OU1, Phoenix, Arizona (GRAA Addendum) reports

September and December 2005

Source area well MP-03 has not been sampled since December 9, 1997. Source area well MP-03 should be added to the monitoring plan and sampled annually. Freescale on-goingMP-03 contains DNAPL and will be added to the monitor list once free product is no longer present.

on-going

ADEQ is concerned that the strong downward vertical gradient at DM606 may indicate that deep bedrock capture in that area is inadequate. A slight increasing TCE concentration trend in the 330 feet bgs port of this well increases this concern.

An analysis and explanation of the DM606 hydraulic and water quality data should be provided Freescale on-going

Freescale conducted an evaluation of this area during shutdown of the treatment systemfrom December 2001 to February 2002. A discussion of the results was provided in the 2001 Effectiveness Report. However, this area is still problematic and issues regarding the vertical gradient remain.

on-going

Increasing TCE trends are observed in wells DM306, DM305, DM307, DM312, and DM 313. ADEQ will continue to monitor the TCE trends in these wells.

TCE trends in wells DM306, DM305, DM307, DM312, and DM 313 should be closely monitored and discussed in future Effectiveness Reports. Freescale on-going Freescale has included a trend discussion in

subsequent Effectiveness reports. on-going

Extraction well DM313 currently exceeds the MCL for TCE. This well must be put back into operation. In addition, should future increasing trends be observed in extraction well DM312 that exceeds the MCL, this well must also be put back into operation.

Extraction well DM313 should be put back into operation. If increasing TCE trends are observed in extraction well DM312 (exceeding the MCL), this well should also be put back into operation.

Freescale when required

DM-312 and DM-313 continue to be monitored during annual sampling events. Concentrations in DM-312 remain relatively low. Concentrations in DM-313 remain close to the MCL.

on-going

DM306 was set to run in cyclic mode, 30-minutes on and 1-hour off. Operation of this well in cyclic mode indicates that the extraction system may need to be modified to address capture of contaminants within the bedrock.

Operation of extraction wells (e.g.- DM306) in cyclic mode indicates that the system may be entering a new phase of operation. A plan that addresses current and future extraction well rate changes and their effect on the OU1 system and bedrock capture should be developed and submitted.

Freescale 3/29/2002 Freescale evaluated DM-306 in the 2001 Effectiveness Report. 3/29/2002

TCE concentrations are increasing in the shallow bedrock ports (170 feet) of DM603 and DM605. This may be the result of TCE contaminant migration from deeper bedrock fractures.

An analysis and explanation of the increasing TCE concentrations in the shallow bedrockports of DM603 and DM605 should be provided. Freescale 3/29/2002 Freescale evaluated DM-603 and DM-605 in

the 2001 Effectiveness Report. 3/29/2002

A plan should be provided that includes an analysis and evaluation of the current downgradient monitoring well network. Freescale 3/29/2002

Freescale evaluated this in the 2001 Effectiveness Report. However, the downgradient monitor well network remains a concern.

3/29/2002

A plan to ensure adequate future downgradient monitoring with the addition of new groundwater monitoring wells, if determined necessary, should be submitted. The plan should also address the potential changes in bedrock extraction as water levels continue to decline.

Freescale 3/29/2002Freescale evaluated this in the 2001 Effectiveness Report. However, this issue remains a concern.

3/29/2002

There are no wells immediately downgradient and outside the capture zone that can be used to confirm that the plume is contained. ADEQ is concerned, particularly since the alluvium is becoming dewatered, that downgradient monitoring in the bedrock is limited.

Page 1 of 4

Table 3 - Actions Taken Since the Last Five-Year Review for OU1Motorola 52nd Street Superfund Site

Phoenix, Arizona

Issues from Previous Review Recommendations/Follow-up Actions Party Responsible

Milestone Date Action Taken and Outcome Date of Action

An analysis and explanation of the TCE concentrations in wells EW18 and DM125 should be provided. Freescale

Freescale evaluated this in the 2001 Effectiveness Report. However, this issue remains a concern.

Groundwater monitor well DM26 should be added to the current OU1 network and monitored annually. Freescale This monitor well is monitored as part of the

Motorola 56th Street Site.

Groundwater data indicated that vinyl chloride is detected more frequently and at higher concentrations exceeding MCLs in some of the wells associated with OU1.

Vinyl chloride should be closely monitored and discussed in future Effectiveness Reports. Vinyl chloride should be added to the OU1 COCs. Freescale Vinyl chloride is evaluated in the

Effectiveness Reports.

While dewatering of the alluvium indicates the success of the alluvial extraction system and alluvial capture, it changes the dynamics of the OU1 extraction and treatment system: 1) As water levels decline and the alluvium isdewatered, the total extraction rate will be reduced. Both extraction and treatment system design changes will be necessary to handle the reduced flow. 2) ADEQ is concerned that as alluvial aquifer is dewatered, the effectiveness of bedrock capture may be reduced. Freescale submitted an analysis of capture in bedrock in the 1994 Effectiveness Report. According to the model, "pressure changes associated with a significant draw down in the alluvium are transmitted to great depth in the bedrock." This concept depends on pressure changes in the alluvium to induce capture in bedrock. This concept was demonstrated by the results of a three-dimensional numeric model discussed in the Appendix. If the alluvium is dewatered how can pressure changes be transmitted to bedrock fractures not connected to the extraction wells?

A plan should be provided that addresses the following: 1) An updated conceptual site model (CSM) that incorporates dewatering of the alluvium. The CSM should address effectiveness of bedrock capture as the alluvium is dewatered. It may be useful to update the 1994 numeric model to aid in the analysis of the system. 2) Any OU1 design changes necessary to maintain capture, especially in bedrock. 3) Any OU1 monitoring well network changes necessary to assess the performance of the system as conditions change.

Freescale 3/29/2002

A discussion of these issues was provided in the 2001 Effectiveness Report. Additional discussion was provided in the GRAA. However, these issues remain problematic.

3/29/2002

The CO required that an SVE system be installed at the ATP. The site inspection and document review confirmed that no SVE system was installed in the ATP.

Freescale should provide documentation as to why an SVE system was not installed or required at the ATP. Freescale 3/29/2002

Freescale has indicated that soil data in the ATP area suggests that SVE remediation may not be applicable. Freescale has provided ADEQ with a plan to evaluate the soil at the Courtyard and SWPL areas first and then the ATP area. ADEQ has agreed to this plan.

3/29/2002

The SVE system within the Courtyard area was not operated in a cyclic mode prior to shut down. In addition, no confirmatory soil sampling was performed.

The SVE system within the Courtyard should be operated in a cyclic mode. Cyclic operation entails turning the system on and off for short periods of time to allow equilibration of the subsurface vapors and flow pathways in an effort to remove the remaining low concentrations of VOCs. Cyclic operation will entail two weeks of system operation, followed by two weeks off for flow pathway equilibrium. Each time the SVE system is restarted, a vapor sample should be collected and analyzed. Once two consecutive vapor samples are near or below the laboratory reporting limits, after surginghas begun, Freescale should collect confirmatory soil boring samples. Prior to conducting any work, Freescale should submit a work plan to ADEQ.

Freescale 3/29/2002

Freescale has submitted a work plan to ADEQ for obtaining closure for the Courtyard soils. ADEQ is currently waiting for the Arizona Soil Rule to be finalized before determining evaluation criteria.

on-going

No confirmatory soil sampling was performed after the shut down of the SVE system within the SWPL area.

Confirmatory soil samples should be collected in the areas impacted by the SVE system at the SWPL area. Prior to conducting any work, Freescale should submit a work plan to ADEQ.

Freescale 3/29/2002 A No Further Action was issued by ADEQ on November 15, 2002. 11/15/2002

A Site Review and Update for the Motorola 52nd Street Superfund Site has not been conducted by ADHS since 1996.

ATSDR has plans to conduct a Site Review and Update for the Motorola 52nd Street Superfund Site. ATSDR NA

ADHS prepared a Status Verification of Private Drinking Water Wells, Motorola 52nd Street Superfund Site report

4/17/2002

The Baseline Risk Assessment and the Health Assessments recommend to increase the frequency of monitoring Mr. Morgan's well. The well has not been sampled in years, however, this may be due to access issues.

Freescale should develop a plan to notice Mr. Morgan (or current owner), gain access to the well, sample on a periodic basis, provide analytical results to Mr. Morgan (or current owner), and take other actions, if necessary.

Freescale on-going Access issues remain on-going

The increasing TCE trend found in wells EW18 (alluvium/bedrock) and DM125(125 foot bedrock port) indicated that the migration of TCE may not be contained in the northern boundary of the plume. The concentrations of TCE found in these northern wells also indicated that TCE is not completely defined to the north. 3/29/2002 3/29/2002

Page 2 of 4

Table 3 - Actions Taken Since the Last Five-Year Review for OU1Motorola 52nd Street Superfund Site

Phoenix, Arizona

Issues from Previous Review Recommendations/Follow-up Actions Party Responsible

Milestone Date Action Taken and Outcome Date of Action

Property owners have the right to install an "exempt" well for any type of use which cannot be restricted by ADWR. The potential future use of "exempt" wells by individual property owners has never been evaluated for OU1. An institutional control may need to be considered.

ATSDR is currently assessing the well surveys that have been conducted at the Motorola52nd Street Superfund Site. A well use survey should also be conducted within the Site. If the results of the survey confirms future use of "exempt" wells by property owners, institutional controls should be considered.

Freescale & ATSDR NA

ADHS prepared a Status Verification of Private Drinking Water Wells, Motorola 52nd Street Superfund Site report

4/17/2002

ADHS identified a private well (Willis) in the 1992 Baseline Risk Assessment that is located within OU1. However, no information regarding the well is provided except that it is "closed".

ATSDR should investigate the status of the Willis well during the next Site Review and Update. ATSDR NA The Willis well was abandoned in June 1990. June 1990

The Turnage well that was locked in 1986 to prevent its use and access is controlled by Freescale. This well is not monitored to ensure the integrity of thelock and the well. Additionally, it is unclear as to the status of ownership of the well.

Freescale should conduct semiannual inspections of the Turnage well to ensure that the well has not been tampered with. Additionally, the owner of the well must be identified and Freescale should consider transferring ownership since they are responsible for ensuring no one has access to the well. If the Turnage well has no use to the Motorola 52nd Street Superfund Site, Freescale should consider abandoning the well.

Freescale 3/29/2002 The Turnage well was abandoned in January 2005. 1/25/2005

The ADHS Soil Gas Sampling Risk Assessment (March 1992) concluded that concentrations of 1,1-DCE are high enough to suggest that further study of potential indoor exposures may be warranted, including collecting air samples from residences. This issue is not addressed in the ADHS Baseline Risk Assessment (November 1992) or in subsequent ATSDR Health Assessments.

ADHS should determine if 1,1-DCE and any other VOCs are still a concern for indoor air exposure. ADHS NA

Toxicity levels for certain VOCs including 1,1-DCE have been revised recently. Revisions to the toxicity value for 1,1-DCE indicates a lower risk from exposure than previously thought.

on-going

Inspection of the IGWTP revealed that the secondary containment system's protective coating was cracking, peeling, and/or lifting up.

The IGWTP secondary containment system's protective coating should be repaired to fix all areas that were cracking, peeling, and/or lifting. Freescale 3/29/2002

Due to exposure to sun and the elements, repairs to treatment system parts is an on-going process. Repairs will be completed as needed.

on-going

The PVC valve at the Liquid Chlorine Feed system looked brittle. The PVC valve at the Liquid Chlorine Feed system should be replaced. Freescale 3/29/2002 The valve was replaced following ADEQ's Second Five-Year Review site inspection. March 2001

The pressure gauge on Air Stripper AS-201 was not functioning. The non-functioning pressure gauge on Air Stripper AS-201 should be replaced. Freescale 3/29/2002The pressure gauge was replaced following ADEQ's Second Five-Year Review site inspection.

March 2001

Well vault MP-11 was full of water.Water that has accumulated in well vault MP-11 should be removed. Freescale should ensure that O&M of the well vaults are maintained to prevent any potential problems due to rainfall/runoff.

Freescale on-going

Well vaults in low-lying areas are inspected after every significant rainfall and pumped out as necessary. The vault for MP-11 was flooded due to ON Semiconductor's testing of a nearby fire hydrant. The vault was pumped put immediately after ADEQ's Second Five-Year Review site inspection.

March 2001

The treated effluent monitoring plan was not available on site. The treated effluent monitoring plan should be made available on site for future inspections. Freescale NA The effluent monitoring plan is contained in

the IGWTP O&M manual at the IGWTP. 3/1/2001

the PQGWWP was not available on site. The PQGWWP should be available on site for future inspections. Freescale

The PQGWWP was previously kept in the main part of the 52nd Street facility when it was owned by Motorola. The PQGWWP will be kept at the IGWTP in the future.

3/1/2001

The IGWTP effluent data and air emissions data were not available on site. The IGWTP effluent data and air emissions data should be available on site for future inspections. Freescale NA Results of effluent data and air emissions

data will be kept at the IGWTP. 3/1/2001

Page 3 of 4

Table 3 - Actions Taken Since the Last Five-Year Review for OU1Motorola 52nd Street Superfund Site

Phoenix, Arizona

Issues from Previous Review Recommendations/Follow-up Actions Party Responsible

Milestone Date Action Taken and Outcome Date of Action

The perimeter fencing around the IGWTP did not completely surround the system, and locks were not provided on the access gates.

Because Freescale does not own the entire facility, it is highly recommended that the perimeter fencing be fully extended around the IGWTP. In addition, all access gates to the system should be kept locked when unattended by authorized OU1 Maintenance personnel.

Freescale NA

Due to space limitations and the need for ON Semiconductor personnel to access adjacent buildings, it is not feasible to extend fencing around the entire IGWTP. However, ON Semiconductor does recognize the area as restricted space and allows access by authorized personnel only.

NA

Perimeter signs that warns of unauthorized entry were of insufficient number tocover the entire perimeter of the IGWTP.

Perimeter signs that warns of unauthorized entry should be placed around all sides of theperimeter fence around the IGWTP. Freescale NA Signs were added to the existing fencing. NA

Review of the SWPL RI report indicates that a typo was made in Tables F.4 and F.5 regarding the unit; "ug/mg" should actually be "mg/kg".

The SWPL RI report should be amended to correct the "unit" typos in Tables F.4 and F.5, and the revised sections resubmitted to ADEQ. Freescale NA Freescale provided an errata sheet correcting

the typographical error. 3/1/2001

The 1992 Baseline Risk Assessment may be outdated based on current site conditions for consideration in the final remedy.

Because decrease in contaminant concentrations may have occurred, which ultimately reduces risk, it is recommended that the 1992 baseline risk assessment be updated to reassess these new site conditions, prior to the selection of the final remedy. Reduction in risk would play an important role in the nature and type of the final remedy that is selected.

Freescale, ADEQ, & ADHS NA A final remedy for OU1 has not been selected

yet. NA

Page 4 of 4

Table 4 - Summary of Current Chemical-Specific StandardsMotorola 52nd Street Superfund Site

Phoenix, Arizona

Authority Medium Requirements Requirement SynopsisRemedy Compliance with Current

StandardsFederal Regulatory Requirements

Groundwater Federal safe Drinking Water Maximum Contaminant Levels (MCLs) for organic and inorganic chemicals (40 CFR 141 Subparts B and G)

MCLs have been promulgated for a number of common organic and inorganic contaminants. These levels regulate the concentrations of contaminants in public drinking water supplies, and are considered relevant and appropriate for groundwater aquifers potentially used for drinking water.

Current groundwater conditions in OU1 indicate that many of the contaminants of concern are above their specific MCLs in on-site and off-site wells. However, the ROD/LOD does not establish a level of cleanup for the aquifer. This may be an ARAR for the final remedy.

EPA Region IX. Preliminary Remediation goals (PRGs).

EPA Region IX guidelines establishing concentrations of compounds in tap water considered to be protective of human health.

Current groundwater conditions in OU1 indicate that many of the contaminants of concern are above their specific PRG in on-site and off-site wells. However, the ROD/LOD does not establish a level of cleanup for the aquifer. This may be an ARAR for the final remedy.

Wastewater Federal Pretreatment Standard for total toxic organics (TTO) (40 CFR 469.16).

Specifies that the maximum daily limitation for TTO is 1,370 ppb.

Yes

Soil EPA Region IX. Preliminary Remediation goals (PRGs).

EPA Region IX guidelines establishing concentrations of compounds in soil considered to be protective of human health.

No post remediation confirmatory soil sampling has been conducted in the ATP and Courtyard. However, the ROD/LOD does not establish a level of cleanup for the soil. This may be an ARAR for the final remedy.

Air EPA Region IX. Preliminary Remediation goals (PRGs).

EPA Region IX guidelines establishing concentrations of compounds in air considered to be protective of human health.

This may be an ARAR for the final remedy.

State and Local Regulatory Requirements

Groundwater Arizona Aquifer Water Quality Standards (AWQS), (AAC R18-11-109, AAC R18-11-406)

Statewide aquifer protection standards for organic and inorganic compounds, established for drinking water protective usage. Many of the compound concentrations are comparable to the Federal MCLs. If the AWQSs are more stringent than the MCLs, than the AWQSs should be used.

Current groundwater conditions within the Site have shown that many of the contaminants of concern are above their specific AWQSs in OU1 wells. This may be an ARAR for the final remedy.

ADEQ's (Office of Environmental Health) Human Health-Based Guidance Levels (HBGLs) for the Ingestion of Contaminants in Drinking Water, December 1997

This guidance document lists a variety of compounds that provides different concentration/limits based upon: calculated risk-based ingestion concentrations; MCLs; proposed MCLs; and state laboratory levels of quantitation values.

Current groundwater conditions in OU1 indicate that many of the contaminants of concern are above their specific HBGLs in on-site and off-site wells. However, the ROD/LOD does not establish a level of cleanup for the aquifer. This may be an ARAR for the final remedy.

Page 1 of 2

Table 4 - Summary of Current Chemical-Specific StandardsMotorola 52nd Street Superfund Site

Phoenix, Arizona

Authority Medium Requirements Requirement SynopsisRemedy Compliance with Current

StandardsState and Local Regulatory Requirements

Soil Arizona Soil Remediation Levels (SRLs) and Groundwater Protection Levels (GPLs) (AAC R18-7-205)

SRLs are statewide predetermined remediation standards for residential or non-residential areas depending on the site usage. GPLs are alternate standards which must be used if they are more stringent than the SRLs.

Although the SWPL area has received a NFA, confirmatory samples have not been collected at the ATP and Courtyard areas. While the SRLs and GPLs were promulgated after the ROD/LOD was executed, these standards may be an ARAR for the final soil remedy for the Site.

ADEQ's (Office of Environmental Health) Human Health-Based Guidance Levels (HBGLs) for the Ingestion of Contaminants in Soil, December 1997

This guidance document lists a variety of compounds that provides different concentration/limits based upon calculated risk-based ingestion concentrations.

No confirmatory soil sampling has been conducted in the ATP and Courtyard areas. However, the ROD/LOD does not establish a level of cleanup for the soil. This may be an ARAR for the final remedy.

Wastewater Appendix C1.3.4(3) of the CO Design requirements established in the CO require that treated groundwater effluent does not exceed 100 ppb of the total VOC concentration, if the TTO concentration is less than 186 ppb. If the TTO limit is exceeded for three consecutive months, the VOC limit of the effluent may not exceed 50 ppb of which the TCE concentration must be less than 5 ppb.

Yes

Air Arizona Ambient Air Quality Guidelines ADEQ issues permits to industries and facilities that emit regulated pollutants to ensure that these emissions do not harm public health or cause significant deterioration in areas that presently have clean air.

This may be an ARAR for the final remedy.

Maricopa County Environmental Services Department (MCESD) Rule 200, Section 303

An Air Emissions Permit was issued by MCESD. The permit was subsequently withdrawn after Freescale demonstrated that air emissions were so low that a permit was no longer required.

Yes.

Maricopa County VOC Limitation This standard limits VOC emissions from any source within Maricopa County to less than 3 pounds per day.

Yes

Page 2 of 2

Table 5 - Summary of Action-Specific StandardsMotorola 52nd Street Superfund Site

Phoenix, Arizona

Authority Requirements Requirement SynopsisRemedy Compliance with

ARARs

Federal Regulatory Requirements

"Standards Applicable to Generator of Hazardous Waste" (40 CFR 262). Established as an ARAR in Section 6.3 of the CO.

Provides the management guidelines of the recovered solvents and spent carbon applicable to OU1.

Yes

State and Local Regulatory Requirements

Arizona Administrative Code (AAC) Title 45, Chapter 2 Article 10. Established as an ARAR in Section 6.3 of the CO.

Provides the requirements for the drilling, construction, operation, and abandonment for any type of well which is directly applicable to the extraction and monitoring wells installed for OU1.

Yes

City of Phoenix construction permits and right of way acquisitions. Established as an ARAR in Section 6.3 of the CO.

Provides requirements to obtain construction permits and right of way acquisitions for the construction of the OU1 systems and off-site extraction wells.

Yes

Arizona Revised Statues (ARS) 45-516. Established as an ARAR in Section 6.3 of the CO.

Requires that the operation of the OU1 conform with area groundwater management plans.

Yes

Appendix C1.3.2 of the CO (established ARAR).

This established ARAR requires that OU1 maintain a "zone of capture" by ensuring that the hydraulic gradient is maintained from the edges of the "zone of capture" to the extractions wells to reduce/eliminate the contaminant migration.

Unknown - Additional data must be provided by the Companies

Appendix C1.3.2 of the CO (established ARAR).

Requires that treated groundwaterfrom OU1 be beneficially used at the ON Semiconductor facility.

Yes

Appendix C1.3.2 of the CO (established ARAR).

Requires that the OU1 air stripping tower be equipped with air emission controls as needed to meet Maricopa County requirements Rule 320, Section 302; Rule 330, Section 306; and Rule 200.

Yes

Page 1 of 1

Table 6 - Confirmation of Chemical-Specific Toxicity Values for OU1 AreaMotorola 52nd Street Superfund Site

Phoenix, Arizona

Chemical of Concern Toxicity Value NameSource

(oral/inhal.) Impact on Risk Assessment

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation) 1.9 / 0.3 EPA, 1997

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) 1.5 / 0.031 EPA, 2004

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation) 0.6 / 0.18 EPA, 1999

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) 0.6 / 0.18 EPA, 1999

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation) 0.0061 / 0.081 EPA, 1999

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) 0.031 / 0.019 EPA, 2004

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation) 0.011 / 0.006 EPA, 1999

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) 0.013 / 0.007 EPA, 2004

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation) 0.029 / 0.027 EPA, 1999

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) 0.055 / 0.027 EPA, 2004

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation) 0.052 / 0.002 EPA, 1999

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) 0.54 / 0.021 EPA, 2004

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation)

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) 0.011 / 0.011 EPA, 2004

Impact on the risk assessment de minimis.

Impact on the risk assessment needs to be evaluated.

Impact on the risk assessment de minimis.

Not Previously Evaluated

Impact on the risk assessment needs to be evaluated.

Impact on the risk assessment needs to be evaluated.

Tetrachlorethene

Toxicity Value

Vinyl Chloride

1,1-Dichloroethene

COCs with Carcinogenic Endpoint

Impact on the risk assessment de minimis.

Chloroform

Trichloroethene

Benzene

Impact on the risk assessment needs to be evaluated.

1,4-Dioxane

Page 1 of 4

Table 6 - Confirmation of Chemical-Specific Toxicity Values for OU1 AreaMotorola 52nd Street Superfund Site

Phoenix, Arizona

Chemical of Concern Toxicity Value NameSource

(oral/inhal.) Impact on Risk AssessmentToxicity ValueCancer Slope Factor [SF]

(mg/kg-day)-1Previous (oral/inhalation)

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) 0.057 / 0.056 EPA, 2004

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation)

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) 0.2 / 0.2 EPA, 2004

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation)

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) 0.0075 / 0.0016 EPA, 2004

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation)

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) 0.062/0.062 EPA, 2004

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation)

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) 0.13 / 0.053 EPA, 2004

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation)

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) 1.5 / 15 EPA, 2004

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation)

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) NL / 420 EPA, 2004

Not Previously Evaluated

Not Previously Evaluated

Not Previously Evaluated

Not Previously Evaluated

Not Previously Evaluated

Not Previously Evaluated

Impact on the risk assessment needs to be evaluated.

1,1,2,2-Tetrachloroethane Impact on the risk assessment needs to be evaluated.

Arsenic Impact on the risk assessment needs to be evaluated.

Carbon Tetrachloride Impact on the risk assessment needs to be evaluated.

1,1,2-Trichloroethane Impact on the risk assessment needs to be evaluated.Not Previously Evaluated

Total Chromium Impact on the risk assessment needs to be evaluated.

Bromodichloromethane Impact on the risk assessment needs to be evaluated.

Methylene Chloride

Page 2 of 4

Table 6 - Confirmation of Chemical-Specific Toxicity Values for OU1 AreaMotorola 52nd Street Superfund Site

Phoenix, Arizona

Chemical of Concern Toxicity Value NameSource

(oral/inhal.) Impact on Risk AssessmentToxicity Value

Reference Doses (mg/kg-day)

Previous (oral/inhalation) 0.1 / 0.14 EPA, 1997

Reference Doses (mg/kg-day)

Current (oral/inhalation) 0.1 / 0.14 EPA, 2004

Reference Doses (mg/kg-day)

Previous (oral/inhalation) 0.09 / 0.3 EPA, 1991

Reference Doses (mg/kg-day)

Current (oral/inhalation) 0.28 / 0.63 EPA,2004

Reference Doses (mg/kg-day)

Previous (oral/inhalation) 0.02 / 0.02 EPA, 1999

Reference Doses (mg/kg-day)

Current (oral/inhalation) 0.02 / 0.02 EPA, 2004

Reference Doses (mg/kg-day)

Previous (oral/inhalation)

Reference Doses (mg/kg-day)

Current (oral/inhalation) 0.01 / 0.01 EPA,2004

Reference Doses (mg/kg-day)

Previous (oral/inhalation)

Reference Doses (mg/kg-day)

Current (oral/inhalation) 30 / 8.6 EPA,2004

Reference Doses (mg/kg-day)

Previous (oral/inhalation) 0.02 / 0.017 EPA, 1999

Reference Doses (mg/kg-day)

Current (oral/inhalation) 0.02 / 0.017 EPA, 2004

Reference Doses (mg/kg-day)

Previous (oral/inhalation)

Reference Doses (mg/kg-day)

Current (oral/inhalation) 0.2 / 0.11 EPA,2004

Reference Doses (mg/kg-day)

Previous (oral/inhalation)

Reference Doses (mg/kg-day)

Current (oral/inhalation) 0.1 / 0.29 EPA,2004

Not Previously Evaluated

Not Previously Evaluated

Toluene Impact on the risk assessment de minimis.

cis-1,2-Dichloroethene Impact on the risk assessment de minimis.

Chlorobenzene Impact on the risk assessment de minimis.

Trichlorotrifluoroethane (F-113) Impact on the risk assessment de minimis.

Not Previously Evaluated

Ethylbenzene Impact on the risk assessment de minimis.Not Previously Evaluated

COCs with Noncarcinogenic Effects

Impact on the risk assessment de minimis.

1,1,1-Trichlorethane

trans-1,2-Dichloroethene

1,1-Dichloroethane Impact on the risk assessment de minimis.

Impact on the risk assessment de minimis.

Page 3 of 4

Table 6 - Confirmation of Chemical-Specific Toxicity Values for OU1 AreaMotorola 52nd Street Superfund Site

Phoenix, Arizona

Chemical of Concern Toxicity Value NameSource

(oral/inhal.) Impact on Risk AssessmentToxicity ValueReference Doses

(mg/kg-day)Previous (oral/inhalation)

Reference Doses (mg/kg-day)

Current (oral/inhalation) 0.2 / 0.0057 EPA,2004

Reference Doses (mg/kg-day)

Previous (oral/inhalation)

Reference Doses (mg/kg-day)

Current (oral/inhalation) 0.0005 / NL EPA,2004

Reference Doses (mg/kg-day)

Previous (oral/inhalation)

Reference Doses (mg/kg-day)

Current (oral/inhalation) 0.000066 / NL EPA,2004

Reference Doses (mg/kg-day)

Previous (oral/inhalation)

Reference Doses (mg/kg-day)

Current (oral/inhalation) 0.006 / NL EPA,2004

Notes:NL - Not Listed

Not Previously Evaluated

Not Previously Evaluated

Impact on the risk assessment de minimis.

Boron Impact on the risk assessment de minimis.Not Previously Evaluated

Not Previously Evaluated

Thallium Impact on the risk assessment de minimis.

Cadmium

Fluroide Impact on the risk assessment de minimis.

Page 4 of 4

Table 7 - Identified Issues and Noted Concerns for OU1Motorola 52nd Street Superfund Site

Phoenix, Arizona

Current Future

1

Capture and containment can only be confirmed with an adequate monitor well network that provides both groundwater level data to demonstrate hydraulic capture and groundwater quality data to demonstrate overall reduction of mass within and outside the capture zone(s). Additional groundwater elevation and quality data are needed to adequately evaluate the OU1 system. The monitoring network needs to be evaluated and updated based on current site conditions and issues.

Unknown Unknown

2

Based on a conservative interpretation of the data, using converging lines of evidence, it appears that capture of the TCZ in bedrock is uncertain. Additional bedrock monitor wells are needed to address the uncertainty of capture in bedrock both downgradient of the on-site system (DM-125, DM-601, and DM-606 areas) and the OCC system (between OCC and DM-118, DM-119, DM-120, DM-122, DM-123, DM-502, and DM503 area). Freescale has installed one multiport bedrock well; however, an increased monitor well network is needed to support the assessment of capture in bedrock.

Unknown Unknown

3

Based on a conservative interpretation of the data, using converging lines of evidence, it appears the TCZ in the vicinity of EW-18 is questionable. Additional alluvial and bedrock monitor wells are needed in the vicinity of EW-18 to address the extent of contamination and evaluate capture of the TCZ.

Unknown Unknown

4

Extraction primarily from the alluvial aquifer is credited for hydraulic capture atsubstantial depth in the bedrock aquifer. ADEQ is concerned that declining groundwater elevations at the site due to both regional decline and OU1 pumping will reduce the effectiveness of bedrock capture. As yield from the alluvial aquifer decreases, resulting changes in the predicted vertical capture needs to be addressed. The potential finite capacity of the system to capture bedrock contamination as the regional aquifer continues to decline representsa potential remedy problem.

Unknown Unknown

5

Concentrations in extraction well DM-313 are currently very close to the MCL for TCE. Concentrations in this well have been increasing slightly over the last three years. If concentrations continue to increase and exceed the MCL, this well must be put back into operation.

No Unknown

6ADEQ is concerned that the source area interim remedy is not significantly effective in reducing the levels of contaminants due to the DNAPL in the fractured bedrock. ADEQ is concerned that high concentrations of TCE will continue in the source area wells for a long period of time.

Yes Unknown

7

Groundwater concentrations in the shallow bedrock ports of DM-125 and DM-601 appear to be increasing. These data indicate that the onsite groundwater extraction system may not be reducing or eliminating contaminant migration from the source area.

Yes Unknown

8Confirmatory soil sampling should be conducted at the Courtyard to obtain closure. Soil sampling should be conducted once the Arizona Soil Rule and guidance has been finalized.

Yes Unknown

9

The CO required that an SVE system be installed at the ATP. No active soil remediation has been conducted in the ATP area to date. Soil sampling should be conducted at the ATP to obtain closure once the Arizona Soil Rule and guidance has been finalized.

Yes Unknown

Groundwater Source Removal

Protectiveness Affected?# Type Issues

Groundwater Capture

Soil

Page 1 of 2

Table 7 - Identified Issues and Noted Concerns for OU1Motorola 52nd Street Superfund Site

Phoenix, Arizona

Current FutureProtectiveness Affected?

# Type Issues

10 Changes to the toxicity levels for certain contaminants have occurred since the last five-year review. Unknown Unknown

11

New methodology is being developed for indoor air risk evaluation. Once the methodology is finalized or EPA and ADEQ can agree to the process for evaluating the pathway, an indoor air risk evaluation should be performed for the OU1 area.

Unknown Unknown

12The Baseline Risk Assessment and Health Assessments recommended to sample Mr. Morgan's well. Access may be an issue for sampling this well. A plan should be developed regarding this well.

Unknown Unknown

13 There is a potential for unregistered, private wells to exist in the OU1 Area. Unknown Unknown

14 The secondary containment system's protective coating showed signs of weathering (e.g.., cracking, peeling, lifting). No Unknown

15 All PVC piping, valves, and other appurtenances showed signs of ultraviolet light weathering (e.g.., brittle appearance). No Unknown

16 The stainless steel steam pressure tanks were stress corroded and cracked. No Unknown

17 Most steel appurtenances showed signs of rusting and/or corrosion. No Unknown

18 The COCs should be identified for the final remedy. No Unknown

19Air emissions and influent/effluent analytical data are an important tool for evaluating the effectiveness of the treatment system and should be reported in the annual Effectiveness Reports.

No Unknown

20 Additional upgradient sources to groundwater contamination may exist. No Unknown

Notes

EPA - Environmental Protection Agency

VOC - Volatile Organic Compounds

ATP - Acid Treatment PlantCOP - City of Phoenix

IGWTP - Integrated Groundwater Treatment PlantMCL - Maximum Contaminant LevelPQGWWP - Poor Quality Groundwater Withdrawal Permit

TCE - TrichloroetheneSWPL - Southwest Parking Lot areaSVE - Soil Vapor Extraction

General

ADEQ - Arizona Department of Environmental Quality

Health Assessment

O&M

Page 2 of 2

Table 8 - Follow-up Actions and Recommendations for OU1Motorola 52nd Street Superfund Site

Phoenix, Arizona

Reference Number* Follow-up Actions/Recommendations

Responsible Party

Oversight Agency

Completion Date

1, 2, 3

A work plan should be prepared and submitted to ADEQ to address the OU1 data gaps identified in Section 8.1.1. The work plan should include a summary of the current conceptual site model, a review of the existing OU1 groundwater monitoring well network and other available data, identify the data gaps, and propose the work necessary to fill the data gaps.

Freescale, ADEQ ADEQ 9/28/2007

4

A work plan should be prepared and submitted to ADEQ to address the bedrock hydraulic conductivity and extraction issues. The work plan should include the installation of a deep bedrock extraction and monitor wells such that a bedrock extraction pilot study may be completed to evaluate bedrock hydraulic conductivity. The results of the study should be incorporated into the feasibility study for the final remedy.

Freescale ADEQ 9/28/2007

5

Freescale should prepare a plan to monitor the concentrations in DM-313. If these concentrations continue to increase and exceed the MCL, the well should be put back into operation.

Freescale ADEQ 9/28/2007

6

Freescale submitted a Groundwater Remedial Alternatives Analysis report in September 2005 followed by an Addendum to the Groundwater Remedial Alternatives Analysis report in December 2005 evaluating treatment technologies for DNAPL. The report is currently under review by ADEQ.

Freescale, ADEQ ADEQ 12/29/2006

7Freescale should prepare a plan to evaluate the effectiveness of the source area treatment system. Freescale ADEQ 9/28/2007

8

Freescale should develop a work plan to evaluate the vadose zone at the Courtyard area. The work plan should include evaluation criteria for clean-up. ADEQ will provide Freescale with the evaluation criteria once the Soil Rule and guidance is finalized.

Freescale, ADEQ ADEQ

1 year following

promulgation of Soil Rule

and Guidance

9

A work plan should also be developed for obtaining closure at the ATP. The closure criteria will be established once the Soil Rule and guidance is finalized and should be included in the work plan.

Freescale, ADEQ ADEQ

1 year following

promulgation of Soil Rule

and Guidance

10A review of the toxicity values for COCs at the Site should be conducted before the final remedy is selected. ADEQ, EPA ADEQ,

EPA ongoing

11

Freescale has previously prepared a work plan to address the vapor intrusion to indoor air pathway. Once the guidance for evaluating the vapor intrusion to indoor air pathway is finalized or EPA and ADEQ can agree to the process for evaluating the pathway, an indoor air risk evaluation should be conducted at the Site. The work plan should be updated to meet the final guidance requirements.

Freescale, ADEQ ADEQ

1 year following

ADEQ and EPA

agreement on process

Follow-up Actions

Page 1 of 2

Table 8 - Follow-up Actions and Recommendations for OU1Motorola 52nd Street Superfund Site

Phoenix, Arizona

Reference Number* Follow-up Actions/Recommendations

Responsible Party

Oversight Agency

Completion Date

12

ADEQ and Freescale should develop a plan to collect groundwater samples from Mr. Morgan’s well and take further actions if necessary.

Freescale, ADEQ ADEQ 9/28/2007

13

ADEQ issues a fact sheet every other year to all the addresses listed within the Motorola 52nd Street Superfund Site. ADEQ will include a note in the next fact sheet requesting owners to notify ADEQ of any private well.

ADEQ ADEQ 9/28/2007

14The secondary containment system's protective coating should be repaired. Freescale ADEQ 9/28/2007

15The PVC piping, valves, and other appurtenances that show signs of weathering should be replaced. Freescale ADEQ 9/28/2007

16The stainless steel steam pressure tanks should be replaced if they are brought back into use. Freescale ADEQ 9/28/2007

17Steel appurtenances that show signs of rusting and/or corrosion should be replaced. Freescale ADEQ 9/28/2007

18

ADEQ and Freescale should establish a list of COCs for the Site. Once the list has been established, Freescale should conduct a sampling round to evaluate the COC list for the RAOs for the final remedy.

Freescale ADEQ 9/28/2007

19

Freescale should include the air emission and groundwater influent/effluent analytical data in the annual Effectiveness Reports.

Freescale ADEQ 9/28/2007

20ADEQ will conduct a PRP search for upgradient sources and will evaluate whether these sources will impact the remedy.

ADEQ ADEQ 9/28/2007

Notes* Refer to Table 7 for reference numberADEQ - Arizona Department of Environmental QualityADHS - Arizona Department of Health ServicesATP - Acid Treatment PlantCOC - Contaminant of ConcernCOP - City of PhoenixDNAPL - Dense Non-Aqueous Phase LiquidEPA - Environmental Protection AgencyIGWTP - Integrated Groundwater Treatment PlantMCL - Maximum Contaminant LevelO&M - Operation and MaintenanceOU1 - Operable Unit 1PRP - Potentially Responsible PartyPQGWWP - Poor Quality Groundwater Withdrawal PermitRAO - Remedial Action ObjectiveSVE - Soil Vapor ExtractionSWPL - Southwest Parking Lot areaTCE - TrichloroetheneVOC - Volatile Organic Compounds

Page 2 of 2

FIGURES

MOTOROLA 52ND STREET SUPERFUND SITEPHOENIX, ARIZONA

Figure 3OU1 Process and Instrumentation Diagram

? ?

Original drafting and design electronically transferred from Dames & Moore, Design Service Group.Job No. 09448-083-022, Drawing No. 5164-001, Rev. No. 8, Date 1/4/90.Frank Stephenson, Arizona Professional Registration No. 23580.

MOTOROLA 52ND STREET SUPERFUND SITEPHOENIX, ARIZONA

Figure 4OU1 Courtyard SVE Process Flow Diagram

MOTOROLA 52ND STREET SUPERFUND SITEPHOENIX, ARIZONA

Figure 5OU1 SWPL SVE Process Flow Diagram

Appendices and Attachments for this Five-Year Review are available by placing a request using the Customized CERCLIS/RODS Report Order Form.

http://www.epa.gov/superfund/sites/phonefax/rods.htm

SSEECCOONNDD FFIIVVEE YYEEAARR RREEVVIIEEWW

OOPPEERRAABBLLEE UUNNIITT 22

MMOOTTOORROOLLAA 5522NNDD SSTTRREEEETT SSUUPPEERRFFUUNNDD SSIITTEE

PPHHOOEENNIIXX,, AARRIIZZOONNAA

SSEEPPTTEEMMBBEERR 2255,, 22000066

REPORT PREPARATION, CERTIFICATtONS, AND APPROVALS

Report Title: Second Five-Year Review Report for Operable Unit 2, Motorola ~ 2 " ~ Street Superfund Site, Phoenix, Arizona

Report Date: September 25, 2006

Prepared by: Arizona Department of Environmental Quality and LFR Inc.

Kris pbascha11, Remedial Project Manager Arizona Department of Environmental Quality

LFR Inc.

Reviewed and Certified by: w

Samantha L. Roberts, Section Manager Remedial Projects Section Arizona Department of Environmental Quality

Federal Facilities and Site Cleanup Branch U. S . Environmental Protection Agency

Date

Date

Date

PFR Inc.

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Page ii

LFR fnc.

............................................................................. 4.3 System Operations 12

5.0 PROGRESS SINCE THE LAST FIVE YEAR REVIEW ..................................... 13

5.1 Protectiveness Statement from First Five-Year Review ................................. 13

5.2 Status of Recommendations and Follow-up Actions from Last Review ............... 13

5.3 Results of Implemented Actions ............................................................. 13

5.4 Other Progress Made During the Review Period ......................................... 14

............................................................... 6.0 FIVE-YEAR REVIEW PROCESS 16

.................................................................. 6.1 Administrative Components 16

...................................................................... 6.2 Community involvement 16

.............................................................................. 6.3 Document Review 17

.................................................................................... 6.4 Data Review 17

6.4.1 Groundwater Data Review ........................................................... 18 6.4.2 Treatment Plant Data Review ........................................................ 18

6.4.3 Additional Well Installation Data Review ......................................... 19

.................................... 6.4.4 Capture Zone Analysis and Hydraulic Testing 19

....................................................................................... 6.5 Interviews 19

.................................................................................. 6.6 Site Inspection 24

................................................................... 7.0 TECHNICAL ASSESSMENT.. 26

7.1 Question A: Is the remedy functioning as intended by the decision ...................................................................................... documents? 26

7.1.1 Remedial Action Performance and Monitoring Results ......................... 28

7.1.2 System Operations/O&M ............................................................. 37

7.1.3 Costs of System Operations/O&M .................................................. 38

.................................................................. 7.1.4 Monitoring Activities 38

...................................................... 7.1.5 Oppomnities for Optimization 38

.................................. 7.1.6 Early Indicators or Potential Remedy Problems 38

7.1.7 Implementation of Institutional Controls and Other Measures ................. 39

7. 2 Question B: Are the exposure assumptions. toxicity data. cleanup levels. and remedial action objectives (RAOs) used at the time o f the remedy selection stilt valid? ..............................................................

7.2.1 Changes in Standards and To Be Considered .........

LFR Inc .

7.2.2 Changes in Exposure Pathways. Toxicity. and Other Contaminant ......................................................................... Characteristics -39

............................................. 7.2.3 Changes in Risk Assessment Methods -40

................................................... 7.2.4 Progress Towards Meeting RAOs 40

7.3 Question C: Has any other information come to Iight that could call into ................................................ question the protectiveness of the remedy? 41

7.4 Summary of Technical Assessment .......................................................... 41

8.0 ISSUES ..........................~..~.............................................................. 42

8.1 Groundwater Issues ........................................................................... -42

....... ................... 8.1.1 Capture Issues ...............~..m................ 4 2

8.1.2 Future Issues ........................................................................... -42

8.2 Health Assessment Issues ..................................................................... 43

8.3 General Issues ................................................................................... 43

9.0 FOLLOW-UP ACTIONS AND RECOMMENDATIONS .................................... 44 9.1 Follow-up Actions ............................................................................ 4 4

9.1.1 Groundwater FolIow-up Actions .............................................. 4 4

9.2.2 Health Assessment Follow-up Actions ............................................. - 4 5

9.1.3 General Follow-up Actions .......................................................... -45

9.2 Parties Responsible for Implementation ................................................... -45

9.3 Agencies with Oversight Authority .......................................................... 46

9.4 Schedule for Completion ..................................................................... - 4 6

10.0 PROTECTIVENESS STATEMENT ............................................................. 47

I 1.0 NEXT REVIEW .................................................................................... -48

TABLES

1 Chronology of Events at the OU2 Area

2 Summary of Monthly Progress Reports for the OU2 Treatment System

3 Annual O&M Costs for the OU2 Treatment System

4 Actions Taken Since the Last Five-Year Review for OU2

5 S u m r y of Current Chemical-Specific Standards

Page v

6 Summary of Current Action-Specific Standards

7 Confirmation of Chemical-Specific Toxicity Values for OU2 Area

8 Identified Issues and Noted Concerns for OU2

9 Follow-up Actions and Recommendations

FIGURES

Site Vicinity Map

Site Plan

Monitor Well Location Map

OU2 Process FIow Schematic and Hydraulic Profile

OU2 GAC System

OU2 Typical GAC Unit

OU2 Ultraviolet Oxidation U d t - Chemical Storage

OU2 Extraction Well Diagram

APPENDICES

A List of Documents Reviewed

B TCE Concentrations of Alluvial and Bedrock Aquifer and Groundwater Elevations Presented in Effectiveness Reports for 2001 (Baseline), 2002, 2003, 2004, and 2005 Operations

C Capture Zone Analyses

D Public Notice of Five-Year Review

E Groundwater Elevation and Concentration Hydrographs for Selected Wells

F Interview Documentation

G Site Inspection Documentation

H 100% Design Repopl Figure 2.3

/

Page vi

LFR Inc.

ACRONYMS AND ABBREVIATIONS

º F degrees Fahrenheit :g/kg micrograms per kilogram :g/l micrograms per liter A.A.C. Arizona Administrative Code ADEQ Arizona Department of Environmental Quality ADHS Arizona Department of Health Services ADWR Arizona Department of Water Resources ARAR Applicable or Relevant and Appropriate Requirements A.R.S. Arizona Revised Statutes AS air sparging ASRAC Arizona Superfund Response Action Contract AST aboveground storage tank ATP Acid Treatment Plant ATSDR Agency for Toxic Substance and Disease Registry AWQS Aquifer Water Quality Standard bgs below ground surface CAG Community Advisory Group CERCLA Comprehensive Environmental Response, Compensation and Liability Act CIP Community Involvement Plan cis-1,2-DCE cis-1,2-dichloroethylene or cis-1,2-dichloroethene CO Consent Order COC contaminant of concern COP City of Phoenix COS City of Scottsdale 1,2-DCB 1,2-dichlorobenzene 1,1-DCA 1,1-dichloroethane 1,1-DCE 1-dichloroethene DNAPL dense non-aqueous phase liquid DO dissolved oxygen EPA U.S. Environmental Protection Agency ERA Early Response Action Freescale Freescale Semiconductor, Inc. FS Feasibility Study FSP Field Sampling Plan ft/day feet per day ft/ft foot per foot GAC granular activated carbon gpd/ft2 gallons per day per square foot GPI Gutierrez-Palmenberg, Inc. GPL Groundwater Protection Limit gpm gallons per minuteHASP Health and Safety Plan IGWTP Integrated Groundwater Treatment Plant KOC organic carbon partition coefficient lbs/day pounds per day LFR LFR Inc. LOD Letter of Determination

Page vii

LFR Inc.

MCL maximum contaminant level MDL method detection limit MEK methyl ethyl ketone mg/kg milligrams per kilogram mg/l milligrams per liter ml milliliters Motorola Motorola Inc. MRL method reporting limit msl mean sea level MTBE methyl tertiary-butyl ether NAAQS National Ambient Air Quality Standards NCP National Contingency Plan NFA no further action NIOSH National Institute of Occupational Health and Safety NPL National Priority List OSHA Occupational Safety and Health Administration OSWER Office of Solid Waste and Emergency Response OU1 Operable Unit 1 OU2 Operable Unit 2 OU3 Operable Unit 3 PA Preliminary Assessment PCE tetrachloroethylene or tetrachloroethene PID photoionization detector ppb parts per billion ppm parts per million ppmv parts per million by volume PQGWWP Poor Quality Groundwater Withdrawal Permit PRP Potentially Responsible Party PSC Preliminary Site Characterization psi pounds per square inch PTP Pilot Treatment Plant PVC polyvinyl chloride QAPP Quality Assurance Project Plan QA/QC Quality Assurance/Quality Control RAO Remedial Action Objective RAP Remedial Action Plan RCRA Resource Conservation and Recovery Act redox oxidation-reduction RI Remedial Investigation ROD Record of DecisionRSRL Residential Soil Remediation Level SARA Superfund Amendments and Reauthorization Act of 1986 scfm standard cubic feet per minute SI Site Inspection SRL Soil Remediation Level SRP Salt River Project SVE soil vapor extraction SVETS Soil Vapor Extraction and Treatment System SVM soil vapor monitoring

Page viii

LFR Inc.

SWPL Southwest Parking Lot TAG Technical Assistance Grant TBC To Be Considered TCA 1,1,1-trichloroethane TCE trichloroethylene or trichloroethene TCLP Toxicity Characteristic Leaching Procedure TCZ Target Capture Zone TOC total organic carbon trans-1,2-DCE trans-1,2-dichloroethylene or trans-1,2-dichloroethene UST underground storage tank VOC volatile organic compound WQARF Water Quality Assurance Revolving Fund

Page ix

LFR Inc.

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LFR Inc.

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LFR Inc.

EXECUTIVE SUMMARY

The second Five-Year Review for the Motorola 52nd Street Superfund site, Operable Unit 2(OU2), located in Phoenix, Arizona was conducted by LFR Inc. (LFR) on behalf of ArizonaDepartment of Environmental Quality (ADEQ). The third Five-Year Review for Operable Unit 1(OU1) is being conducted concurrently by the ADEQ and LFR. The review period was fromSeptember 30, 2001 through July 2006.

The U.S. Environmental Protection Agency (EPA) is the lead agency for OU2; however, ADEQis conducting this OU2 Five-Year Review on behalf of EPA. EPA and ADEQ are required toconduct this Five-Year Review pursuant to Comprehensive Environmental Response,Compensation and Liability Act (CERCLA) § 121 and the National Contingency Plan (NCP).Together, these regulations require that the remedial actions resulting in any hazardoussubstances, pollutants, or contaminants remaining at the site above levels that allow forunlimited use and unrestricted exposure be reviewed every five years to assure protection ofhuman health and the environment. Since hazardous substances, pollutants, or contaminants areleft on site above levels that allow for unlimited use and unrestricted exposure, this review isrequired for OU2 site. The purpose of the five-year review is to determine whether OU2continues to meet remedial objectives and is protective of human health and the environment.

The five-year review consisted of the following activities: (1) review of relevant documents(Appendix A); (2) interviews with appropriate operations staff, state and federal agencies, localgovernment officials, and concerned community members; and (3) a site inspection.

The assessment identified several issues in the review of the existing OU2 system captureanalyses. These problems include non-conservative interpretation of groundwater data, failure touse all available data, and failing to effectively evaluate the results of specific analyses inconjunction with the conceptual site model. Several data gaps have been identified that need tobe filled in order to fully evaluate the OU2 capture effectiveness. A review of applicable orrelevant and appropriate requirements (ARARs) determined that there are no newly promulgatedstandards that affect OU2; however, new ARARs and To Be Considereds (TBCs) are likely to bedetermined for the final remedy.

A protectiveness determination of the OU2 interim remedy cannot be made at this time due tothe zone of capture issues identified in this review. The follow-up actions and recommendationsidentified under Section 9 are needed to determine protectiveness. The actions will require theefforts of the Companies and agency oversight to be completed. An iterative approach witheffective communication among the stakeholders throughout the recommended actions is neededto address these issues quickly and effectively.

Page xii

___________________________________________________________________________________________LFR Inc.

Site Name: Motorola 52nd Street

EPA ID: AZD009004177

Region: 9 State: Arizona City/County: Phoenix/Maricopa

NPL Status: Final Deleted Other (specify)___________________________

Remediation Status: (choose all that apply): Under Construction Operating Complete

Multiple OUs? Yes No Construction Completion Date: Interim Remedy

Has site been put into reuse? Yes No The site was never out of use.

Reviewing Agency: EPA State Tribe Other___________________

Author Name: Robert Forsberg c/o LFR Inc.

Author Title: Senior Hydrogeologist Author Affiliation: ADEQ Consultant

Review Period: September 2001 to July 2006

Date(s) of Site Inspection: June 6 and 7, 2006

Type of Review: Statutory Policy Post-SARA Pre-SARA NPL-Removal Only

Non-NPL Remedial Action Site NPL State/Tribe-Lead Regional Discretion

Review Number: First Second Third Other________________

Triggering Action:

Actual RA Onsite Construction at OU Actual RA Start at OU

Construction Completion Previous Five-Year Review Report

Other (Specify)___________________________________________________________________

Triggering Action Date: September 28, 2001

Due Date (five years after triggering action date): September 28, 2006

FIVE-YEAR REVIEW SUMMARY FORM

SITE IDENTIFICATION

REVIEW STATUS

SITE STATUS

xiii

___________________________________________________________________________________________LFR Inc.

DEFICIENCIES/ISSUES AND NOTED CONCERNS

13) Consistent interpretation of the hydrostratigraphic subunits and available data is needed for OU2 analyses

xiv

7) The Agencies are concerned that the stagnation zone on the upgradient and downgradient side of the Honeywell bedrock ridge is not being addressed by the OU2 Treatment System.

Groundwater Capture Issues

1) Little to no groundwater elevation and quality data are available in any of the subunits along the north side of the OU2 plume. As a result, the impact of the OU2 treatment system can not be adequately evaluated in that area.2) Groundwater elevation and quality data are lacking in all three subunits along the south side of the OU2 plume. As a result, the impact of the OU2 treatment system is difficult to assess in this area.

FIVE-YEAR REVIEW SUMMARY FORM

Groundwater Future Issues5) EW-S groundwater extraction rates have declined. If the rate declines further in the future, capture to the south may also be reduced.

6) Future containment of the D subunit is problematic because: the D subunit is primarily contaminated in the south portion of OU2, EW-S does not penetrate the D subunit and therefore does not directly extract from the D subunit, and capture is currently questionable and may decrease if EW-S extraction rates continue to decline.

General Issues

9) The OU2 system is an interim remedy and therefore a final remedy for OU2 must be developed. The final remedy will necessarily address the issues identified in this five-year review and must consider and integrate the Honeywell light nonaqueous phase liquid (LNAPL) remedy.

Health Assessment Issues

12) Boron has been detected in influent and effluent samples from the treatment plant.

10) Changes to the toxicity levels for certain contaminants have occurred since the last five-year review.

3) Additional groundwater elevation and quality data are needed downgradient of the OU2 treatment system to evaluate capture in the D 4) Based on a conservative interpretation of the data, using converging lines of evidence, it appears the TCZ along the south side of the plume is not fully captured.

8) Long-term multi-well aquifer tests in subunits B and D are needed to gain a better understanding of the OU2 conceptual site model and to facilitate future OU2 analyses.

11) New methodology is being developed for indoor air risk evaluation. Once the methodology is finalized or EPA and ADEQ can agree to the process to evaluate the pathway, an indoor air risk evaluation should be performed for the OU2 area.

___________________________________________________________________________________________LFR Inc.

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CORRECTIVE ACTIONS AND RECOMMENDATIONS

Groundwater Future Issues Corrective Actions

FIVE-YEAR REVIEW SUMMARY FORM

A protectiveness determination of the OU2 interim remedy cannot be made at this time until further information is obtained. The necessary follow-up actions and recommendations identified in this report are needed to evaluate protectiveness. The actions will require the efforts of the Companies and the Agencies to be completed. It is expected that these actions will take approximately 1 year to complete at which time a protectiveness determination will be made.

PROTECTIVENESS STATEMENT

OTHER COMMENTS

13) The Agencies recommend a technical work group meeting to discuss and address groundwater elevation and quality data, capture issues, and hydrostratigraphic issues.

9) The final OU2 remedy will need to incorporate the Honeywell LNAPL remedy.

General Issues Corrective Actions

5) The Companies should continue to monitor the extraction rates for EW-S.

8) The Companies should develop a plan to conduct long-term multi-well aquifer tests in subunits B and D. The data obtained from these tests will be useful for designing a final remedy for OU2.

11) An indoor air risk evaluation should be conducted at the Site once the guidance for evaluating the vapor intrusion to indoor air pathway is finalized or EPA and ADEQ can agree to a process for evaluating the pathway.

Health Assessment Issues Corrective Actions

12) Effluent samples should be collected and analyzed for boron. If the results are above the surface water limit for agricultural irrigation, SRP should be notified.

7) The Companies should prepare a plan to evaluate the effectiveness of the OU2 treatment system on the stagnation zones upgradient and downgradient of the Honeywell bedrock ridge.

10) A review of the toxicity values for COCs at the Site should be conducted before the final remedy is selected.

6) The Companies should develop a plan to monitor groundwater capture along the southern boundary, particularly in subunit D.

Groundwater Capture Issues Corrective Actions1) A work plan should be prepared and submitted to ADEQ to address the data gaps along the north side of the OU2 plume. The work plan should include the installation of monitor wells in each of the three alluvial subunits.2) A work plan should be prepared and submitted to ADEQ to address the data gaps along the south side of the OU2 plume. The work plan should include the installation of monitor wells in each of the three alluvial subunits.3) A work plan should be prepared and submitted to ADEQ to address the data gaps downgradient of the OU2 treatment system. The work plan should include the installation of monitor wells in the D subunit.4) Future capture evaluations shall include a conservative interpretation of groundwater elevation data, an analysis of water level pairs for appropriately configured monitor wells, capture zone calculations that are conceptually consistent with site data and interpretation, and concentration trend analysis that includes historic data.

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1.0 INTRODUCTION

The Arizona Department of Environmental Quality (ADEQ) and LFR Inc. (LFR) haveprepared this Second Five-Year Review Report for Operable Unit 2 (OU2) at theMotorola 52nd Street Superfund Site, Phoenix, Arizona. LFR conducted the work underArizona Superfund Response Action Contract (ASRAC) EV03-0073 and TaskAssignment 06-0165 dated May 26, 2006. The review period was from September 30,2001 through July 2006.

The purpose of the five-year review is to determine whether OU2 continues to meetremedial objectives and is protective of human health and the environment. The methods,findings, and conclusions of reviews are documented in this Report.

OU2 is part of the Motorola 52nd Street Superfund Site that consists of three operableunits: OU1, OU2, and OU3, as shown on Figure 1. The OU1 area is bounded by PalmLane to the north, Roosevelt Street to the south, 52nd Street to the east, and by the zoneof hydraulic capture to the west (approximately 46th Street). The OU2 area is boundedapproximately by Roosevelt Street to the north, the northern runway of Phoenix SkyHarbor International Airport to the south, the OU1 groundwater capture zone to the east(approximately 46th Street), and by the zone of hydraulic capture to the west(approximately 17th Street). The OU2 treatment system is located on the northwestcorner of the intersection of 20th Street and Washington Street (Figure 2). The OU3study area is bounded by approximately McDowell Road to the north, Buckeye Road tothe south, 20th Street to the east and 7th Avenue to the west. A small cut-out is located inthe southwest corner of the OU3 Study Area approximately defined by Buchanan Streetand 3rd Avenue.

EPA is the lead agency for OU2; however, ADEQ is conducting the OU2 five-yearreview on behalf of EPA. EPA and ADEQ are required to conduct this five-year reviewpursuant to Comprehensive Environmental Response, Compensation and Liability Act(CERCLA) § 121 and the National Contingency Plan (NCP). Together, these regulationsrequire that the remedial actions resulting in any hazardous substances, pollutants, orcontaminants remaining at the site above levels that allow for unlimited use andunrestricted exposure be reviewed every five years to assure protection of human healthand the environment. Since hazardous substances, pollutants, or contaminants are left onsite above levels that allow for unlimited use and unrestricted exposure, this review isrequired for OU2. This review was prepared according to Office of Solid Waste andEmergency Response (OSWER) Directive 9355.7-03B-P, Comprehensive Five-YearReview Guidance, June 2001.

This is the second five-year review for OU2; EPA completed the first Five-Year ReviewReport in September 2001. At the time of the review, the treatment system was underconstruction. The first and second five-year reviews for OU2 were triggered by thefive-year review cycle for OU1. The third five-year review for OU1 is being conductedconcurrently by ADEQ and LFR.

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In 2000, AlliedSignal purchased Honeywell International and assumed the Honeywellname. For the purpose of continuity, Honeywell will be used to refer to both HoneywellInternational and AlliedSignal throughout the Five-Year Review Report.

In December 2004, Motorola spun off its semiconductor sector to form a newindependent company (Freescale Semiconductor). For the purpose of continuity,Freescale will be used to refer to both Motorola and Freescale Semiconductor throughoutthe Five-Year Review Report.

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2.0 SITE CHRONOLOGY

A chronology of OU2 events is included in Table 1.

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3.0 BACKGROUND INFORMATION

3.1 Site Location Information

OU2 is part of the Motorola 52nd Street Superfund Site that consists of three operableunits: OU1, OU2, and OU3, as shown on Figure 1. OU2 is bounded approximately byRoosevelt Street on the north, the northern runway of Phoenix Sky Harbor InternationalAirport on the south, the OU1 area groundwater capture zone on the east (approximately46th Street), and by the zone of hydraulic capture to the west (approximately 17th Street).The OU2 treatment system is located on the northwest corner of the intersection of 20thStreet and Washington Street (Figure 2). The system consists of three groundwaterextraction wells (EWN, EWM, and EWS) and a groundwater treatment system (Figure3). The OU2 Treatment System is operated by Freescale and Honeywell (jointly referredto as the Companies).

3.2 Land and Resource Use

The surrounding area is comprised of a mixture of residential, commercial, and industrialuses. Groundwater within the OU2 area is a potential source of drinking water. Currently,the City of Phoenix (COP) is not using this groundwater as a source for drinking water.However, Salt River Project (SRP) is currently using the groundwater for irrigationpurposes.

3.3 Site History and Operable Unit 2 (OU2) Information

The contamination in groundwater in the OU2 area is the result of cleaning solventreleased into the environment during the late 1950’s to early 1980’s at nearby facilitiesincluding the former Motorola 52nd Street Facility (currently the location of ONSemiconductor) and the Honeywell 34th Street Facility. The Site was listed on theNational Priorities List (NPL) in 1989. Motorola was identified as a responsible party(RP) at that time. Honeywell was identified as a RP in 1992. Several additionalpotentially responsible parties (PRPs) have been identified in the OU2 area. Currently,these PRPs include: D-Velco, Honeywell Area 13, Honeywell Area 21, ITT Cannon,Joray/Kachina, Laundry Cleaners & Supply, and Papago Plating. The PRP search is stillongoing and additional PRPs may be named by the agencies.

The following sections provide a summary of the main site activities associated withOU2. The majority of the site information was obtained from the review of keydocuments associated with OU2. The list of key documents is included in Appendix A.Table 1 provides a brief summary of the chronological history of OU2.

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3.3.1 Site Discovery

In 1982, groundwater contamination was discovered in wells in the OU2 area.Trichloroethene (TCE) was detected in the Desert Hills well (Monroe and 27th Street) at640 parts per billion (ppb) and in the Eastlake Park well (Jefferson and 16th Street) at 44ppb. The groundwater contamination was initially thought to be a separate plume fromthe Motorola 52nd Street Site. ADEQ designated the area as the East Washington Area.

3.3.2 Preliminary Investigation

From 1985 to 1989, ADEQ conducted a remedial investigation and initiated aninvestigation of potentially responsible parties. In 1987, ADEQ designated the area as theEast Washington Water Quality Assurance Revolving Fund (WQARF) Area.

3.3.3 Groundwater Investigation

Between 1990 and 1992, ADEQ and Freescale conducted an area-wide groundwaterinvestigation to define the extent of groundwater contamination in the OU2 area.Approximately 48 monitor wells (with a total of 120 sampling ports) were installed andover 300 aquifer tests were conducted. The area-wide sampling effort confirmed thatcontamination from the Motorola 52nd Street Facility had migrated west into the EastWashington area. As a result, ADEQ and EPA developed a second operable unit (OU2)to address the groundwater contamination before the final remedy was selected.

3.3.4 Health Assessments

ADHS completed a Baseline Risk Assessment in November 1992. The assessmentincluded both OU1 and OU2, however, for the purposes of this five year review, only theOU2 issues will be discussed. The Baseline Risk Assessment concluded that the risk ofpublic exposure to groundwater is limited, and therefore causes no imminent healthhazard.

In April 2002, ADHS conducted a health assessment of the Motorola 52nd StreetSuperfund Site area to identify any current groundwater use that might result in humanexposure to site contaminants. The Report updated the 1992 well use inventory for OU1and OU2 and provided an evaluation of potential groundwater exposure pathways inOU3. The Report concluded that for those wells whose status was verified, no exposureto contaminated groundwater was found; therefore, those wells pose no public healthhazard. However, unregistered private wells might exist within the Motorola 52nd StreetSuperfund Site.

3.3.5 Interim Remedy

In 1993, Freescale submitted a series of reports for developing an interim remedy forOU2 including a flow and transport model, a draft Detailed Analysis of Alternatives

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Report, a draft Interim Remedy Feasibility Study (FS) Report, and an Updated InterimRemedy FS Report.

3.3.6 Decision Documents

In July 1994, ADEQ and EPA issued a Record of Decision (ROD) selecting the interimgroundwater remedy. The purpose of the OU2 interim remedy is to provide additionalcontainment of contaminated portions of the groundwater. The interim remedy includesgroundwater extraction near 20th Street and Washington Street, treatment of water bygranular activated carbon (GAC) and discharge of the treated water to the Grand Canalfor irrigation use. The specified remedial objectives of the ROD are to establish a capturezone across the entire width and depth of the contaminant plume, and to reduceconcentrations of contaminated groundwater within the alluvial aquifer upgradient of theextraction wells. The ROD specified that groundwater will be extracted and treated to alevel at or below Maximum Contaminant Levels (MCLs).

In September 1999, EPA issued an Explanation of Significant Differences to July 1994Record of Decision, Operable Unit Two, East Phoenix Groundwater Containment,Motorola 52nd Street Superfund Site, Phoenix, Arizona (ESD). The ESD modified theinterim remedial action selected by EPA and ADEQ in the July 1994 OU2 ROD becauseof changes to the design. EPA and ADEQ determined that the use of carbon adsorptionand ultraviolet oxidation for treatment of groundwater and the discharge of the treatedwater to the Grand Canal for end-use were efficient and cost effective modifications tothe selected remedy.

3.3.7 ADEQ Consent Decree for OU2 Treatment System Design

In November 1996, a Consent Decree was entered into by ADEQ, Freescale, and the Cityof Phoenix for the design of the OU2 Treatment System. The Consent Decree requiredthe following design performance standards:

1) establishing and maintaining a zone of capture that will prevent groundwater inalluvium and bedrock contaminated with TCE in excess of 5 micrograms per liter(:g/L) from migrating beyond the OU2 Area provided that it does not adverselyimpact on other groundwater remediation programs as determined by the State;and

2) treating the groundwater from the extraction system so that effluent water qualitymeets the applicable standards at point(s) of compliance.

In addition, the treatment system was to be designed to provide beneficial end use of thetreated water.

In July 1999, Freescale submitted the OU2 Final (100%) Design Report. The final designincluded the following components:

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• three groundwater extraction wells (EWN, EWM, and EWS);

• treatment facility with GAC adsorption (and ultraviolet oxidation ifrequired); and

• discharge of treated groundwater to the SRP Grand Canal.

3.3.8 EPA Unilateral Administrative Order and Treatment System Construction,Operation and Maintenance

On November 30, 1998, EPA issued a Unilateral Administrative Order (UAO) to theCompanies for construction, start up, and two years of operation and maintenance(O&M) of the groundwater treatment system. Construction of the treatment system beganin March 2000 and was completed in September 2001. The treatment system becamefully operational on December 31, 2001. A Second Amended UAO was issued onDecember 11, 2003 that required continued O&M of the interim remedy. The UAO alsorequires the Companies to prepare monthly progress reports of O&M activities, quarterlygroundwater monitoring reports, and annual Effectiveness Reports. Conestoga-Rovers &Associates (CRA) was selected by the Companies as the supervising contractor for theO&M.

The monthly progress reports discuss the O&M activities during the reporting period,activities scheduled for the next 45 days, and analytical results of influent, GAC effluent,and facility discharge. Table 2 provides a summary of the monthly progress reports. Fewsignificant issues other than annual SRP Grand Canal shutdowns have been reportedduring this five-year review timeframe. However, in December 2005, the treatmentsystem was shutdown because TCE was detected in the November 2005 facilitydischarge sample at concentrations of 4.1 :g/L and 4.2 :g/L. The system was restartedfollowing change outs of the four primary GAC carbon vessels.

CRA also conducts the quarterly groundwater monitoring as part of the O&M activities.The locations of the OU2 Treatment System wells are shown in Figure 3. The monitoringplan is outlined in the revised O&M Manual; groundwater quality monitoring isperformed semiannually (March and September). However, a subset of monitor wells aremonitored on a quarterly basis as described in the 2004 Effectiveness Report. Theobjectives of the groundwater monitoring program are (1) to provide groundwater qualityand hydraulic data to monitor trends in the groundwater levels and contaminants ofconcern (COCs) and (2) provide data to determine when the groundwater extractionsystem should be modified or discontinued.

The annual Effectiveness Reports provide an assessment of the overall effectiveness ofthe OU2 Treatment System with respect to the treatment system and hydrauliccontainment of contaminated groundwater. The Companies concluded in each of theiryearly evaluations that the OU2 Treatment System has maintained a capture zoneadequate to contain the entire width and depth of the groundwater contaminant plume(Appendix B). The total gallons pumped from OU2, from 2001 through May 2006, were estimated to be 5.23 billion gallons. The total VOCs removed from the groundwater in

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OU2, from 2001 through May 2006, was estimated to be 7,926 pounds. The reportsfurther concluded that the overall trend of VOC concentrations in the groundwatershowed an overall decrease since start up.

3.3.9 First Five Year Review

In September 2001, EPA completed the first five-year review report for OU2. At the timeof the review, the treatment system was under construction. The first five-year reviewfound that the remedy was being constructed in accordance with the requirements of theROD, ESD, and design documents. A protectiveness statement was not issued at the timesince no assessment of the treatment system could be made.

3.3.10 Staged Restart of Extraction Wells

In March 2004, the Companies completed an evaluation of hydraulic capture followingthe staged restart of the OU2 Area extraction wells after the SRP Grand Canal shutdownin February 2004. The evaluation was requested by EPA in a February 2, 2004 letter. Thestaged start-up consisted of re-starting only the middle (EW-M) and southern (EW-S)extraction wells. The initial flow rate at the start-up for the middle extraction well wasapproximately 1,650 gallons per minute (gpm) and for the southern extraction well was200 gpm. Groundwater elevations were monitored in the OU2 treatment systemmonitoring network. Water levels declined almost immediately after starting the twoextraction wells.

The Companies concluded that there was sufficient capture to the north using only themiddle and southern extraction wells. Additionally, capture to the south occurredpotentially south of monitor well EW-06. The Companies requested EPA approval toleave the northern extraction well off and just use the middle and southern extractionwells to achieve plume capture. EPA granted the Companies’ request to leave EW-N offin a letter dated April 8, 2004. However, EW-N was subsequently turned on again tocompensate for the reduction of flow at EW-M on September 23, 2004 (CRA, 2005b).

3.3.11 Capture Zone Calculations

In May 2004, the Companies submitted a letter report presenting an analysis of the extentof the combined capture zone provided by extraction wells EW-M and EW-S to confirmcontainment between the two extraction wells and to show the extent of capture to thesouth. The Companies used three lines of evidence for this evaluation:

• a flow net was manually drawn based on observed groundwater elevationcontours to illustrate the extent of capture provided by EW-M and EW-Sin the Salt River Gravels and in Basin Fill;

• a simple capture zone analysis using the computer code RESSQ was donefor each hydrostratigraphic unit;

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• groundwater chemistry concentration trends at specific monitoring wellswere evaluated to determine the effect of the extraction system on waterquality conditions in the area.

In addition, the Companies provided an updated capture zone analysis in Appendix A ofthe 2005 Effectiveness Report based on data from additional groundwater monitor wellsand piezometers that were installed subsequent to the 2004 analysis. The 2005 analysisfollowed the same procedure noted above using converging lines of evidence todetermine whether capture was being achieved. The Report concluded that the OU2groundwater extraction system (GES) capture zone in the Subunits “A and B” extendsfrom south of EW06 and north of NW09 to the north of CRA01. In Subunit “D”, theOU2 GES capture zone extends from south of EW06 to at least NW12-D to the north.

Copies of these reports are provided in Appendix C. A detailed review of this assessmentis provided in Section 7.

3.3.12 Additional Monitor Well Installations

The Companies installed additional monitor wells near the OU2 Treatment System asrequested by ADEQ and EPA to provide further information on site lithology andgroundwater conditions. Four rounds of drilling have occurred since 2003. Monitor wellsNW04-S, NW04-D, NW05-S, NW06-S, NW06-D, NW07-S, NW07-D, NW08-S,NW08-M, and NW08-D were installed between June and July 2003. NW09-D wasinstalled in January 2004. Monitor wells NW09-D2, NW10-D, NW11-D, and NW12-Dwere installed between January and February 2005. Monitor wells NW07-M, NW09-M,NW13-M, NW13-D, NW14-M, and NW14-D were installed between November andDecember 2005.

3.3.13 Honeywell Remedial Investigation and Action

An investigation of the Honeywell 34th Street Facility began in 1988 upon notice byADEQ. In 1992, EPA issued a general notice letter to Honeywell stating that the 34thStreet Facility may have contributed to the regional groundwater contamination, knownas the Motorola 52nd Street Superfund Site. In 1999, ADEQ and Honeywell entered intoan Administrative Order on Consent (AOC) to complete a focused remedial investigationof the 34th Street Facility. The objective of the AOC was to identify and characterizepotential source areas and to determine the nature and extent of contamination emanatingfrom the Facility. In December 2005, Honeywell submitted the Final Focused RemedialInvestigation Report and is currently under review by ADEQ.

During remedial investigations at the Honeywell Facility, petroleum hydrocarbons weredetected in soil and groundwater. An investigation was initiated under the ADEQUnderground Storage Tank (UST) Corrective Action Section. Honeywell installedseveral monitor wells on and off their Facility to characterize the extent of the petroleumhydrocarbons. Honeywell has determined that a floating free product plume exist under

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the Facility and the Sky Harbor International Airport. The free product plume measuresapproximately 1500 feet by 2500 feet. Honeywell also determined that the free-productplume is composed primarily of Jet-A fuel and is contaminated with chlorinated VOCs.Honeywell developed a corrective action plan (CAP) under UST to address the freeproduct. The CAP recommends the following remedial actions:

• remediate soil contamination in the vadose zone, the free-phasehydrocarbon smear zone, and the free-phase hydrocarbon pool withbioenhanced soil vapor extraction (BSVE);

• supplement BSVE remediation by selectively removing free product fromexisting groundwater monitoring wells.

This remedial action is not part of the ROD, UAO, or ESD for the OU2 area andtherefore has not been reviewed as part of this five-year review process; however, adiscussion of the remedial action is presented below since it will be incorporated into thefinal remedy for OU2

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4.0 REMEDIAL ACTIONS

4.1 Remedy Selection

The OU2 ROD selected an interim groundwater containment remedy for the OU2 Areabetween the Old Crosscut Canal and Interstate 10. The remedy was classified as aninterim action in order to reflect the possibility that additional remedial actions may beneeded. An ESD was issued in September 1999 to modify the requirements of the ROD.

The specified remedial action objectives of the ROD are to establish a capture zoneacross the entire width and depth of the contaminant plume and to reduce concentrationsof contaminated groundwater within the alluvial aquifer upgradient of the extractionwells. The ROD specified that groundwater will be extracted and treated to a level at orbelow MCLs.

The basic components of the selected interim remedy include the following:

• groundwater extraction near 20th Street and Washington Street;

• treatment of water by ultraviolet oxidation and GAC; and

• discharge of the treated water to the Grand Canal for irrigation use.

The OU2 interim remedy evaluated during this five-year review consists of threeextraction wells which are all piped to the OU2 Treatment System. The locations of thekey components of the interim treatment system are shown in Figure 2.

4.1.1 Groundwater Remedy

The groundwater extraction system consists of 3 extraction wells located along 20thStreet. The extraction wells provide hydraulic containment west of Interstate 10. Thereare also a total of 54 monitoring wells within OU2 and OU3 that constitute the OU2Treatment System monitoring network (See Figure 3).

The OU2 Treatment System consists of 18 GAC vessels and one ultraviolet oxidationsystem with hydrogen peroxide pre-treatment. Figure 4 through 8 provide a process flowdiagram of the system and schematics of the system parts. Groundwater from theextraction wells is pumped at a current average rate of 2,150 gpm (600 gpm from EW-N;1,350 from EW-M, and 200 from EW-S) to the treatment plant and through four pairs ofGAC vessels connected in series. Currently, the ultraviolet oxidation system is not inoperation because vinyl chloride has not been detected in groundwater. The treated wateris routed through underground piping to a discharge point on the Grand Canal (Figure 2).Occasional slow flow backflushing of the GAC units is required to flush out the entrainedair from the carbon. The backflushed water is collected in a backwash wastewater tankand subsequently discharged to the City of Phoenix sanitary sewer system. Spent GAC is

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returned to the supplier for regeneration and then returned to the treatment plant.

4.2 Remedy Implementation

The OU2 Treatment System has been in operation since December 31, 2001. Thegroundwater extraction system is designed to treat approximately 5,300 gpm and receivesgroundwater from 3 extraction wells. Currently, due to dewatering of the alluvium, thetreatment system is operated at approximately 2,150 gpm. As of May 31, 2006, thetreatment system processed approximately 5.23 billion gallons of groundwater, fromwhich approximately 7,926 pounds of VOCs have been removed. A monthly update ofthe remedy progress is included in Table 2.

4.3 System Operations

For the operation of the treatment system, the Companies retained the services of CRA toconduct all O&M and monitoring activities. Daily maintenance activities are performedby CRA in accordance with the updated July 2004 Revised Final Operation andMaintenance Manual, 20th Street Groundwater Treatment Facility, 52nd StreetSuperfund Site, Operable Unit 2 Area, Phoenix, Arizona.

In 2001, O&M costs for the treatment system was approximately $415,702. These costsreflected the timing of start-up and commissioning of the OU2 system. O&M costsincreased to $1,027,508 in 2002. The costs for 2003, 2004, and 2005 were $776,431,$1,009,540, and $828,500, respectively. From 2002 to 2005, the O&M costs weregenerally consistent. Table 3 provides the annual O&M costs from 2001 to 2005. Thesecosts do not include other response costs that were incurred for OU2 (e.g., agencyoversight costs).

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5.0 PROGRESS SINCE THE LAST FIVE YEAR REVIEW

5.1 Protectiveness Statement from First Five-Year Review

The First Five-Year Review for OU2 was completed by EPA on September 28, 2001. Atthe time of the Report, a protectiveness determination of the OU2 remedy could not bemade until further information was obtained. EPA provided a list of actions that neededto be completed before a protectiveness statement could be issued. EPA issued thefollowing statement with regard to the OU2 remedy:

A protectiveness determination of the remedy at OU2 cannot be made at this timeuntil further information is obtained on the issues that affect protectiveness.Further information will be obtained by the following actions: 1) ADHS willcomplete the public health assessment on groundwater use in the area; and 2) theprevious risk calculations will be reviewed in light of changes to both inhalationtoxicity values and the model used to project indoor air risks from subsurface.Also, more evaluation needs to be conducted by EPA to ensure the remedy willachieve the hydraulic containment standards. An addendum will be prepared byEPA within 6 months to reassess the protectiveness of the remedy. In themeantime, the groundwater treatment system is meeting the required treatmentstandards, and the exposures at the site have been restricted through institutionalcontrols to address immediate health threats: drinking water is being supplied tothe public by the City of Phoenix, and ADWR permitting requirements on newgroundwater wells provide a mechanism for which groundwater use may beidentified and monitored. The site Health and Safety Plan is current and on-site,is sufficient to control health risks, and is being properly implemented.

5.2 Status of Recommendations and Follow-up Actions from Last Review

Table 4 presents a summary of the status of the recommendations and follow-up actionsfrom the First Five-Year Review. Most of the recommendations and follow-up actionswere addressed by the Companies; however, several of the issues raised continue to beproblematic. Monitor well coverage to the north, south, and downgradient of thetreatment system remains sparse. Since a final remedy for OU2 has not yet beendeveloped, issues regarding final ARARs and institutional controls have yet to beaddressed.

5.3 Results of Implemented Actions

The following paragraphs discuss some of the results of the implemented actions fromthe First Five-Year Review. Table 4 summarizes the actions taken and outcomes for eachissue raised during the First Five-Year Review.

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The Companies have evaluated the lower than expected extraction rates from EW-S.While the extraction rate for EW-S has been steady at approximately 200 gpm since late2003, the lower than expected rate remains a concern for the future effectiveness of theremedy. Further discussion is provided in Section 7.1.

The Companies finalized the O&M Manual in January 2002 and updated it in July 2004.However, there is still some question as to whether the monitor well network is sufficientto adequately evaluate capture. Further discussion is provided in Section 7.1.

Institutional controls have been implemented by ADEQ regarding access to contaminatedgroundwater. Since WQARF was revised in 1997, ADEQ and ADWR have developed aprocedure whereby ADWR notifies ADEQ when a Notice of Intent (NOI) to Drill aMonitor Well within the Motorola 52nd Street Superfund Site has been filed. ADEQ canthen notify the property owner of the risk involved with using the groundwater.

Additionally, in April 2002 ADHS conducted a health assessment of the Motorola 52ndStreet Superfund Site area to identify any current groundwater use that might result inhuman exposure to site contaminants. The Report updated the 1992 well use inventoryfor OU1 and OU2 and provided an evaluation of potential groundwater exposurepathways in OU3. No additional wells were found.

Since the last five-year review, EPA and ADEQ have not evaluated any additionalARARs since a final remedy for the OU2 Area has not been selected.

Groundwater sampling was conducted in 2001 and 2002 to evaluate additionalconstituents in groundwater. Groundwater samples were collected and tested for VOCs,metals, inorganics, and cyanide. In addition to the known VOC COCs, boron wasdetected slightly above the surface water limit for agricultural irrigation.

The evaluation of indoor vapor intrusion within the OU2 Area is pending the completionof the OU1 Area assessment. The OU1 Area may represent a worst case scenario for thevapor intrusion since concentrations are higher and the groundwater table is shallowerthan any other area of the Motorola 52nd Street Site. This has not yet been conductedsince the guidance for conducting indoor air pathway evaluations is still draft. Once theguidance is finalized, or EPA and ADEQ can agree to the process for evaluating thepathway, the indoor air pathway evaluation should be conducted.

5.4 Other Progress Made During the Review Period

The following progress was made in the operation of OU2 since the last review:

• start-up and operation of the OU2 Treatment System. As of May 31, 2006,approximately 7,926 pounds of VOCs have been removed andapproximately 5.23 billion gallons of groundwater have been remediatedand returned to beneficial use;

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• additional monitor wells were installed to provide additional data forevaluating the effectiveness of the system.

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6.0 FIVE-YEAR REVIEW PROCESS

6.1 Administrative Components

The 52nd Street OU2 Five-Year Review was lead by Kris Paschall, Project Manager ofADEQ, who provided oversight of the review process that was conducted by LFR(ADEQ’s consultant). The following team members took part in the review:

• Kris Paschall, ADEQ Project Manager;

• David Haag, ADEQ Project Hydrologist;

• Robert Forsberg, LFR Project Manager;

• Bradley Cross, LFR Principal Hydrogeologist;

• Ned Overs, LFR Professional Engineer;

• Michael Nesky, LFR Senior Engineer;

• John Kivett, LFR Senior Hydrologist;

• Laura Malone, LFR Senior Project Scientist;

• Nadia Hollan, EPA Project Manager.

The five year review consisted of the following activities: (1) review of relevantdocuments (Appendix A); (2) interviews with appropriate operations staff, state andfederal agencies, local government officials, and concerned community members; and (3)a site inspection.

6.2 Community Involvement

A public notice regarding the initiation of the forthcoming review was mailed to theMotorola 52nd Street mailing list in April 2006 (Appendix D). The final report isavailable at ADEQ and the local site repositories which are located at the Central Branchand the Saguaro Branch of the City of Phoenix public libraries. ADEQ will provide abrief summary of this Report to community members by holding a public meeting and/ordistributing a fact sheet.

Additional community involvement activities during this five-year review periodincluded periodic community advisory group (CAG) meetings, update of the communityinvolvement plan (CIP), and involvement with the Technical Advisory Grant (TAG)Lindon Park Neighborhood Association.

The CIP was updated in March 2002 and again in July 2004. ADEQ conducted severalinterviews with the OU2 community to gather information for both of these updates. The

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primary concerns of the community in OU2 related to having access to enoughinformation about the project, health impacts, the current status of contamination, andunderstanding the proposed cleanup.

Both EPA and ADEQ worked with the TAG recipient, Lindon Park NeighborhoodAssociation, during this review period. In addition, EPA and ADEQ have held periodicCAG meetings to discuss activities and the status of OU2. Minutes from these CAGmeetings are available for review in the repositories and on ADEQ’s website.

6.3 Document Review

The following primary site documents have been reviewed:

• Baseline Health Risk Assessment, Motorola 52nd Street Facility, Phoenix,Arizona, prepared by ADHS, November 1992

• Record of Decision, Operable Unit Two East Phoenix GroundwaterContainment, Motorola 52nd Street Superfund Site, Phoenix, Arizona,July 1994

• Amended Unilateral Administrative Order, #98-15, Motorola 52nd StreetSuperfund Site, November 1998

• Final (100%) Remedial Design Report, Operable Unit 2 Area, Motorola52nd Street Superfund Site, Phoenix, Arizona, July 1999

• Explanation of Significant Differences (ESD#1) to July 1994 Record ofDecision, Operable Unit Two East Phoenix Groundwater Containment,Motorola 52nd Street Superfund Site, Phoenix, Arizona, September 1999

• Technical Memorandums and supporting information prepared by CRA onbehalf of Freescale and Honeywell

• Final Remedial Action Report for Motorola 52nd Street Superfund Site,Operable Unit 2 Area, Phoenix, Arizona, September 2003

• Revised Final Operation and Maintenance Manual, 20th StreetGroundwater Treatment Facility, 52nd Street Superfund Site, OperableUnit 2 Area, Phoenix, Area, July 2004

• The following routine documentation: Monthly OU2 Progress Reports,Quarterly Groundwater Monitoring Reports, Annual OU2 EffectivenessReports (December 2001 – present)

6.4 Data Review

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evaluation. A review of ARARs is discussed in Tables 4, 5, and 6.

6.4.1 Groundwater Data Review

Since the interim remedy was primarily implemented to reduce the concentration ofcontamination and to capture the migrating plume, the groundwater data reviewevaluated trends in groundwater concentrations in key areas around the treatment system.Data from monitor wells downgradient of the extraction wells were used to evaluate theeffectiveness of capture and to determine whether the plume was being containedvertically and horizontally.

The groundwater monitoring network that is monitored in the OU2 Area consists of wellslocated in the vicinity of the OU2 Treatment System. The network consists of monitorwells in OU2 and OU3, and some of the wells monitored include wells in the Honeywell34th St Facility network. These monitor wells are used to collect groundwater elevationand water quality data from the alluvium and bedrock upgradient, downgradient, andcross-gradient from the treatment system. The locations of the wells are shown on Figure3. Groundwater samples collected from these wells are analyzed for VOCs and selectedinorganic compounds. Hydrographs of groundwater elevations and concentrations forselected wells are provided in Appendix E.

Groundwater quality monitoring is performed semiannually in March and September. Asagreed upon, following the submittal of the 2004 Effectiveness Report, a subset of themonitor wells south of the southern extraction well was monitored quarterly for one year.This recommendation was extended through 2006.

The main analytes that are detected most frequently exceeding their respective MCLs areTCE, tetrachloroethene (PCE), 1,1-dichloroethene (1,1-DCE), and cis-1,2-dichloroethene(cis-1,2-DCE). Boron has been detected in groundwater samples slightly above thesurface water limit for agricultural irrigation. In addition, sampling for metals in soils atthe Papago Plating facility, an identified PRP in OU2, indicated elevated levels of metalsabove Arizona Non-residential Soil Remediation Levels (SRLs) including chromium andnickel. Cadmium, chromium, lead, and nickel concentrations exceeded their GroundwaterProtection Limits (GPLs) indicating the potential for continued threat to the groundwater.

A groundwater sample collected in 1996 from the Alamo well MW-1 indicatedconcentrations of chromium above the MCL of 0.1 ppm. Groundwater samples collectedin 2001 prior to start-up of the treatment system did not indicate concentrations ofchromium above the MCL (IT Group, 2003).

6.4.2 Treatment Plant Data Review

Another primary requirement of the ROD is to treat the extracted groundwater to meetMCLs. Treatment plant influent and effluent data are collected on a monthly basis. Theeffluent results were compared to the established MCLs. Based on the data provided bythe Companies in monthly Progress Reports, none of the constituents exceeded theMCLs.

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Available copies of historical design and engineering documents, record drawings,treated effluent monitoring plan, the City of Phoenix Polluted Groundwater DischargePermit, the groundwater treatment plant (GWTP) effluent monitoring records/data,liquid-phase carbon change out records, waste profiling data, and manifests of the spentcarbon sent off-site for regeneration and recycling were reviewed. During the inspection,ADEQ and LFR reviewed the GWTP records, including: daily/bi-weekly/monthlyoperating logs, equipment calibration logs, maintenance logs, and other documents toassess operation and maintenance compliance.

6.4.3 Additional Well Installation Data Review

ADEQ and LFR reviewed additional well construction completion reports prepared byCRA on behalf of the Companies. The data was used to evaluate the lithology of the OU2Area. In addition, groundwater samples and elevations from the new wells were used inconjunction with the quarterly groundwater sampling data to evaluate the vertical andhorizontal extent of the plume within each subunit.

6.4.4 Capture Zone Analysis and Hydraulic Testing

ADEQ and LFR reviewed data obtained following the staged restart of the extractionwells following the annual winter shutdown and the Capture Zone Calculations –Operable Unit 2 Letter Report dated May 28, 2004. ADEQ and LFR also reviewed theupdated capture zone analysis provided in Appendix A of the Effectiveness Report –2005, 52nd Street Superfund Site, Operable Unit 2 Area Report. The data was used toevaluate the vertical and horizontal extent of capture and the effectiveness in plumecontainment of the OU2 extraction wells.

6.5 Interviews

The following individuals were interviewed for OU2 during this five-year review processby personal contact or by telephone:

• Tom Suriano, Remediation Project Manager, Freescale Semiconductor –Interviewed on May 10, 2006 at the ADEQ office.

• Nadia Hollan, Project Manager, EPA – Interviewed on May 10, 2006 atthe ADEQ office.

• Martha Breitenbach, CAB Member – Telephone interview on May 23,2006.

• Karen O’Regan, Environmental Programs Director for the City of Phoenix– Interviewed May 25, 2006 at the ADEQ office.

• Dave Gordon of Malcolm Pirnie and Chris Mattison representing Joray –Telephone interview on May 25, 2006.

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• Steve Whillier, Manfred Plaschke and Dave Hilliard of Conestoga Rovers& Associates provided a written response to the interview questions onJune 1, 2006.

• George Ring of CH2M Hill (representing Troy Meyer of Honeywell) –Interviewed on June 9, 2006 at the ADEQ office.

• Donn Stoltzfus, Environmental Program Specialist, City of Phoenix –Telephone interview on July 21, 2006.

The following individuals were invited to interview and ADEQ either received a declineto interview or did not receive a response:

• Steve Brittle – Don’t Waste Arizona • Daniel Casiraro – Salt River Project • Mario Castenada – Gateway TAG technical consultant • Jeff Conover – Walker Power • Janet Corrigan – Paul McCoy’s Laundry • Gine Flury – AdobeAir • Andrew Frisbie – Wabash National • Linda Furlough – Arvin Meritor • Richard Guimond – Motorola • John Held – Phoenix Newspapers • Mark Hess – Cooper Industries • Judith Heywood – APS • Kenneth Hodson – BDR Liquidating • Ed Honig – Union Pacific Railroad • Michael Johnson – City of Phoenix Councilman • John Maris – D-Velco • Scott Miller – AZ. Department of Water Resources • Teresa Olmstead – ITT Industries • Tommy Padgett – Citizen – Requested interview, but was not available • Cynthia Parker – City of Phoenix Aviation Department • Stephen Smith – BDR Liquidating • Greg Stanton – City of Phoenix Councilman • Douglas Watson – Joray

The detailed accounts of the interviews are presented in Appendix F, which are brieflysummarized in the following paragraphs. Concerns or questions raised during theinterviews will be addressed in a responsiveness summary prepared following the 30 daypublic comment period.

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Mr. Tom Suriano, Remediation Project Manager, Freescale Semiconductor. Mr.Suriano of Freescale Semiconductor, in conjunction with Honeywell, is responsible forthe O&M of the OU2 interim remedy. Mr. Suriano is familiar with all aspects of theproject and was familiar with all O&M and monitoring activities. Excerpts of hisresponses are as follows. OU2 is a containment remedy that captures contaminants in thevicinity of I-10 and includes all the PRPs that have contributed. OU2 is effective atachieving the objectives. Freescale and Honeywell have contracted with ConestogaRovers & Associates for O&M, and reporting issues. Mr. Suriano stated that therehaven’t been any O&M problems or activities that would have affected the protectivenessor effectiveness of OU2. Regional drought has decreased water levels and studies havebeen performed to show that the remedy is still capturing. Due to the declining waterlevels, adjustments have been made in flow rates and optimization of the system hasoccurred to achieve capture. Mr. Suriano provided several recommendations including:(1) completing the O&M Consent Decree with ADEQ, (2) completing the PRPevaluation, and (3) oversight is fairly high at OU2 and the agencies should consider areduction in oversight.

Nadia Hollan, Project Manager, EPA Region 9. Ms. Hollan oversees the Companies inregards to the implementation and operations at OU2. Excerpts of her responses to theinterview are as follows. There is a Unilateral Administrative Order with Honeywell andFreescale. The OU2 remedy is an interim groundwater containment remedy. OU2 hasbeen doing what it was intended to do. There are questions on capture due to thedeclining water levels and the unknown areas of contamination on the south side of thesystem, which need to be addressed. EPA has published fact sheets, conducted publicmeetings, and continues to work with ADEQ. Periodically, there have been inquiriesmade to EPA on OU2. Specific details could not be remembered, however, the majorityof the inquiries were minor issues. Ms. Hollan is aware that there are communityconcerns on whether the water discharged to the Grand Canal has been treated to safelevels. Ms. Hollan was unaware of any new regulations or guidance that would affect theoperation of OU2. She stated that the public record reflects all the communicationsand/or EPA’s thoughts on the overall system. In regards to recommendations, Ms. Hollanstated that new COCs may be an issue and that there needs to be follow up on theevaluation of the vapor intrusion issue.

Martha Breitenbach, CAB Member. Ms. Breitenbach has been a member of theMotorola 52nd Street Superfund Site CAG for approximately 5 years and participates inCAG meetings. Excerpts of her responses to the interview are as follows. OU2 is a pumpand treat system similar to OU1, with the only difference being the jet fuelcontamination. Ms. Breitenbach expressed disappointment that the resolution is slow andthat more aggressive action should be taken. Ms. Breitenbach is very concerned that theplume is growing. She stated that Honeywell is not amenable to anyone describing whereto put their wells and that Honeywell installed wells without ADEQ approval. She seesthis as skewing the results. Ms. Breitenbach stated that she has been kept well informedon the monitoring well issues and that the written materials provided are helpful.However, she would appreciate seeing raw data rather than averaged data. Ms.Breitenbach would also like to see points on a graph that show concentrations and what

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contamination is left. She would also like to see more information on how much wasreleased.

Karen O’Regan, Director of the Environmental Programs Department, City ofPhoenix. Ms. O’Regan is a representative of the City of Phoenix and is involved inissues regarding the redevelopment of the Site. Excerpts of her responses to the intervieware as follows. OU2 is a groundwater containment system and is working fairly well.There are boundary issues associated with OU2 as they relate to containment. There is aconcern that OU2 is dewatering the aquifer. The City of Phoenix is copied on associatedOU2 reports. The City hasn’t really received any citizen complaints regarding OU2, otherthan general questions on what the treatment system is. Ms. O’Regan stated that she wasunaware of any new regulations/guidance that would affect OU2. Development in thearea includes the new light rail system and associated redevelopment of certain areas.Ms. O’Regan stated that vapor intrusion is a top issue for the City, along with OU3, andthe declining water levels. In regards to vapor intrusion, there aren’t any standards andthe guidance is controversial and she would appreciate some appropriate guidance onhow to handle this issue. Ms. O’Regan stated a concern regarding the Honeywell’s plumeand how Honeywell has determined the extent. She also expressed concern regardingHoneywell’s pilot test for air emissions and what impacts it will have on the residents.Ms. O’Regan recommended that Councilman Mattox, Cynthia Parker, and DonnStoltzfus be interviewed.

David Gordon, Malcolm Pirnie and Chris Mattison representing Joray. Mr. Gordonis the consultant representing Joray and Chris Mattison is an attorney also representingJoray. Excerpts of their responses to the interview are as follows. OU2 is an interimremedy for the groundwater contamination. The system seems fairly sufficient, but isaware that there is the AFFC fuel issue and was not sure this was accounted for. Mr.Gordon stated that he feels he has been kept informed about all phases of the project andthat he is not aware of any events or incidents affecting OU2. Mr. Gordon stated that he,as well as others, (as expressed in open house meetings) would like to see more rapidprogress.

Steve Whillier, Manfred Plaschke and Dave Hilliard with Conestoga Rovers &Associates (CRA). CRA has been retained as the supervising consultant by Freescaleand Honeywell to conduct all O&M and monitoring activities. Mssrs. Whillier, Plaschke,and Hilliard provided a written response to the interview questions. Excerpts from theirwritten responses are as follows. OU2 is an interim remedy and was implemented onSeptember 26, 2001. OU2 is a groundwater extraction and treatment system. OU2objectives are to fully contain the entire north-south width and depth of the VOCcontamination plume in the vicinity of 20th Street. OU2 includes 3 extraction wells andthe treated water meets discharge standards. Since system startup, OU2 has beeneffective in capturing and containing the groundwater plume at approximately 20th Streetand has treated approximately 4.8 billion gallons of groundwater and removed over 7,300pounds of VOCs. OU2 is working as designed.

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Changes to the OU2 groundwater monitoring network and extraction wells have beendocumented in reports submitted to EPA. Other O&M optimization activities haveincluded reducing flow rate set points due to the regional drought, the number of GACvessels has decreased, and the UV oxidation is not being used since vinyl chloride hasnot been detected. CRA states that there have been no issues that have adverselyimpacted the effectiveness of the remedy.

Changes in monitoring activities include the removal and addition of monitoring wells tothe overall monitoring network. Monitoring has increased in both location and frequencyfrom the original plan. Annual O&M costs are consistent with original costs.

The Companies make recommendations in each annual effectiveness report for the nextyear of O&M. These recommendations are included in their written response.

George Ring, Hydrogeologist with CH2M Hill. Mr. Ring has been retained by andrepresented Troy Meyer of Honeywell. Excerpts of his responses to the interview are asfollows. OU2 is an interim remedy and a feasibility study is currently being conducted todevelop the final remedy. OU2 consists of 3 extraction wells and the groundwatertreatment system. Mr. Ring stated that the remedy is functioning and is capturing theplume and treating the water to applicable standards. He indicated that there are no issuesor problems with OU2 or any significant changes to the system, other than the monitoringwell network has been expanded in order to answer some questions regarding capture.Difficulties with O&M are of a routine nature and have not impacted the effectiveness.Mr. Ring stated that the declining water levels are a big issue and that flow rates havebeen adjusted accordingly. Ms. Paschall asked questions regarding capture and whetherthere was a point at which declining water levels would impact the extent of capture. Mr.Ring stated that they have not gotten to that point.

Mr. Ring stated that the annual O&M costs are consistent within an order of magnitudeand that costs may even be a little bit lower due to smooth system operations.

Mr. Ring stated that overall things are going well; the parties have a good relationshipand are fairly responsive to getting issues resolved.

Donn Stoltzfus, Environmental Program Specialist, City of Phoenix. Mr. Stoltzfus isa representative of the City of Phoenix. Excerpts from his interview are as follows. OU2is a groundwater treatment system and is relatively successful at what it was designed todo. The City of Phoenix is involved due to redevelopment issues and the potential for thefuel plume at the Sky Harbor Airport to co-mingle with the Superfund Site. The City isalso concerned about groundwater resources in the area. Mr. Stoltzfus stated that vaporintrusion is also a concern with the Site. He stated that his office has provided briefingsto city council members and department heads regarding OU2. He is not aware of anycomplaints received by his office or any community concerns regarding OU2. He is alsonot aware of any planned changes to regulations/ordinances that would impact the Site.He stated that he thought the O&M and monitoring activities have been implemented in

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accordance with approved plans and stated that he has been kept informed of OU2activities. He would like to see more coordination between ADEQ’s Superfund and USTprograms. These programs seem to have different approaches, philosophies andobjectives and coordination between the programs would be very helpful.

6.6 Site Inspection

Representatives of ADEQ, LFR, CRA, CH2M Hill, Hargis & Associates, and Freescaleconducted a site inspection of the OU2 Treatment System on June 6 and 7, 2006. Theinspection was lead by Kris Paschall, Project Manager for ADEQ, and Robert Forsberg,Project Manager for LFR. Other inspection participants included Michael Nesky and NedOvers with LFR, David Haag with ADEQ, George Ring with CH2M Hill (representingHoneywell), Mike Long with Hargis & Associates (representing Honeywell), and TomSuriano with Freescale. The inspection was supported by Manfred Plaschke, ProjectManager for CRA, Steve Whillier and David Hilliard with CRA, Operations Supervisorof CRA, who guided the inspection team around the OU2 Treatment System andanswered questions from the inspection team. The treatment system inspection wasperformed using a checklist prepared by LFR. The completed checklist is included inAppendix G.

The site inspection involved the following activities:

• conducting interviews with onsite operators;

• reviewing documents that are maintained off site and on site;

• visual inspection of the OU2 Treatment System.

Weather conditions during the inspection were favorable, sunny with high temperatures.No problems were encountered with access to relevant site features inspected. Thetreatment system inspection was conducted to provide information regarding the O&Mstatus and document the conditions of the treatment plant.

Prior to performing the site inspection, ADEQ and LFR reviewed available copies ofdesign and engineering documents, record drawings, treated effluent monitoring plan, theCity of Phoenix Polluted Groundwater Discharge Permit, the GWTP effluent monitoringrecords/data, liquid-phase carbon change out records, waste profiling data, and manifestsof the spent carbon sent off-site for regeneration and recycling. During the inspection,LFR reviewed the GWTP records, including: daily/bi-weekly/monthly operating logs,equipment calibration logs, maintenance logs, and other documents to assess operationand maintenance compliance. No significant issues with record keeping were discovered,and all operation and maintenance activities were being performed in compliance withoriginal and/or modified design specifications.

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A discussion of the annual O&M costs is included in Section 4.3. The costs for 2001reflect the start-up and commissioning of the OU2 system, 2002 costs reflect the first fullyear of operation, and from 2002 to 2005 the costs were generally consistent.

In general, the OU2 GWTP remediation system was in excellent condition and operatingwithin specified ranges. No other significant or minor issues were noted during theinspection.

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7.0 TECHNICAL ASSESSMENT

In accordance with the Comprehensive Five Year Review Guidance (Guidance), datedJune 2001, the five year review should determine if the remedy is protective of humanhealth and the environment and that it satisfies the performance criteria set forth in thedecision documents. In order to assess the protectiveness of the remedy, the technicalassessment should address three questions:

Question A: Is the remedy functioning as intended by the decision documents?

Question B: Are the exposure assumptions, toxicity data, cleanup levels, andremedial action objectives (RAOs) used at the time of the remedyselection still valid?

Question C: Has any other information come to light that could call intoquestion the protectiveness of the remedy?

Pursuant to the Guidance, these questions were developed as the framework fororganizing and evaluating data and information, and to ensure that all relevant issues areconsidered when determining the protectiveness of the remedy.

The following subsections will examine each of these questions in detail.

7.1 Question A: Is the remedy functioning as intended by the decisiondocuments?

The following sections discuss the performance of the OU2 remedy. The technicalassessment included reviewing the following:

• remedial action performance and monitoring results;• system operations/O&M; • costs of the system operations/O&M; • monitoring activities; • opportunities for optimization; • early indicators of potential remedy problems; and • implementation of institutional controls and other measures.

The relevant decision documents are summarized in Section 3.3.6. The OU2 RODpresents the selected remedial action and identifies the performance standards. Accordingto the OU2 ROD, the selected remedial action is an interim remedy designed to addressgroundwater that is contaminated with VOCs in the OU2 area. The major components ofthe remedy are:

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• extraction of groundwater in the vicinity of Interstate 10 and Van BurenStreet;

• treatment of extracted water near extraction locations by either airstripping with off-gas treatment by synthetic resin adsorption, oradvanced oxidation based on final design considerations;

• injection of treated water back into the aquifer in a location allowingadditional control of the contaminant plume.

The OU2 ROD also identifies the performance standards for the remedy and establishesthat the remedy will comply with the respective ARARs. The OU2 ROD notes thatcleanup of the aquifer to drinking water standards is not an ARAR because it is beyondthe scope of this interim action for OU2: no ARARs waiver are expected to be needed.

The UAO and superseding Amended UAO direct the Respondents to implement theremedial action and perform operation and maintenance for the interim remedy describedin the OU2 ROD. The Amended UAO includes a detailed Statement of Work which setsforth the framework and requirements for implementing the OU2 interim remedial action.The Amended UAO (Section VI, ¶ j.) requires the Respondents to meet the PerformanceStandards identified in the ROD and the Statement of Work attached to the UAO.

The ESD modifies the interim remedial action selected in the OU2 ROD due todevelopments during the design of the groundwater treatment system for OU2. The OU2ROD specified either air stripping or ultraviolet oxidation as a treatment technology andreinjection as a beneficial end-use of treated groundwater. EPA and ADEQ havedetermined that the use of carbon adsorption and ultraviolet oxidation for groundwatertreatment and the discharge of the treated groundwater to the Grand Canal for end-useare efficient and cost effective modifications to the selected remedy (ESD, page 1). TheESD also establishes that the revised remedy remains protective of human health and theenvironment.

In summary, the above described decision documents establish the primary performancestandards for the OU2 interim remedy as:

• establish and maintain a capture zone across the entire width and depth ofthe contaminant plume near Interstate 10 and Van Buren Street;

• remove and permanently destroy groundwater contamination abovedrinking water standards; and

• discharge treated water to the SRP Grand Canal to be used for agriculturalirrigation and agricultural livestock.

Technical assessment of the later two performance standards were evaluated byconfirming effective operation of the treatment system. Technical assessment of thecapture zone is complex and requires converging lines of evidence as discussed in the

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section below.

7.1.1 Remedial Action Performance and Monitoring Results

In order to effectively assess groundwater contaminant capture, an evaluation of the OU2interim remedy based on the systematic approach developed by EPA using six basic stepsfor capture zone analysis was performed. These steps use “converging lines of evidence”and an iterative approach to assess capture (Capture Zone Analyses for Pump-and-TreatSystem, EPA Training Course hand-outs presented to the State of Arizona, May 25,2005). The following guidance documents were also used to perform the analysis:

• Methods for Monitoring Pump-and-Treat Performance, U.S. EPA, Officeof Research and Development, 1994 (EPA 600-R-94-123)

• Elements for Effective Management of Operating Pump and TreatSystems, U.S. EPA, Office of Solid Waste and Emergency Response,2002 (EPA 542-R-02-009)

7.1.1.1 Step 1: Review site data, site conceptual model, and remedy objective.

The review of site data was summarized in Section 6.4.

Conceptual Site Model

The Site is located in the eastern part of the City of Phoenix. There is a mixture ofresidential, commercial, and industrial land use in the area overlying the Site. Accordingto the 1992 RI Report, completed by Freescale, and the 2005 Honeywell Focused RIReport, releases of hazardous substances from the former Motorola 52nd Street Facilityand the Honeywell International, Inc. 34th Street Facility impacted soil and groundwaterand the combined releases from their source areas have created an extensive groundwatercontaminant plume (Figure 1). Additional potentially responsible parties may have alsocontributed to the groundwater plume. The contaminants of concern are primarily TCE,TCA, and their reductive daughter products. These contaminants seeped into thesubsurface, though the vadose zone, and have mixed into and spread with thegroundwater.

The Site is situated in the western Salt River Valley of the Basin and RangePhysiographic Province characterized by alluvial-filled basins bounded by fault-blockmountain ranges (Reynolds and Bartlett, 2002). The 1992 RI Report identifies threehydrogeologic units: an upper coarse sandy gravel, and underlying clayey sandy gravel,and bedrock. Recent investigations by Honeywell (2005 Focused RI Report) generallyconfirm these findings. Reynolds and Bartlett identified the upper coarse-grained alluvialunit as the Salt River Gravel and the lower finer-grained unit as “Basin Fill”. Basin Fillwas also identified as having interbedded fine and coarse deposits.

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Investigations conducted by the Companies and, farther to the west in the OU3 StudyArea by EPA, have identified a slightly more complex alluvial stratigraphy. Aconsistently identified fine-grained subunit has been observed in drilling samples in themajority of deeper borings advanced in western OU2 and within OU3. This subunit hasbeen identified as the “D” subunit. It is characterized as finer-grained interbeds of sandysilt with clay and coarser-grained interbeds of sand with gravel and lesser amounts of siltand clay. The overlying “B” subunit is characterized by finer-grained interbeds of sandysilt with clay and coarser-grained interbeds of gravely sand with cobbles and lesseramounts of silt and clay. These two subunits have also been collectively referred to as the“Basin Fill” unit. The overlying “A” subunit is characterized by gravely sand withcobbles and lesser amount of silt and clay. The A subunit is generally identified as SaltRiver Gravels (Reynolds and Bartlett, 2002). Correlation of boring logs also indicatesthat, in general, cobbles are encountered more frequently in the A subunit and aregenerally larger than the cobbles encountered in the B subunit. Review of boring logs inthe OU2 area also indicates that the fine-grained interbeds of the B subunit are notpresent in all boreholes, notably in borings located in the southwest portion of OU2. Theboring logs also indicate that if adequate depth was attained and bedrock was notencountered first, the uppermost fine-grained interbed of the D subunit generally isencountered at a consistent depth. Boring logs to the east of the OU2 system (e.g., east ofBC-11A) indicate that the D subunit is pinched-out at the Honeywell bedrock ridge.

It should be noted that interpretation of the three subunits is also supported by thefundamental concept that groundwater movement in the alluvial aquifer is generallyhorizontal necessitating correlation of data from similarly screened monitor wells.Groundwater chemistry data also indicates that concentrations of contaminants vary withdepth. Correlation of concentration data from similarly screened wells also supports thishydrostratigraphic interpretation.

Data collected from hundreds of groundwater monitor wells installed duringinvestigations of the Site starting in 1983 indicates that the groundwater table isencountered at depths ranging from approximately 60 ft bgs in the eastern portion of theSite to 100 ft bgs near the west boundary of OU2. Potentiometric maps of these dataindicate groundwater flow under the Site is generally west although locally may beobserved as southwest and northwest. Two subsurface bedrock “ridges” locally impedeand alter groundwater flow. As the predominantly horizontal flowing groundwaterencounters these ridges, groundwater flow divides and moves around the ridges,converging downgradient. Areas of low hydraulic gradient on the upgradient anddowngradient sides of the ridges correspond to the areas of flow divide and convergenceand are also identified as stagnation zones. Both ridge features trend northwest-southeast.The eastern of the two ridges is located under the Honeywell Facility and has asignificant impact on flow in both the A and B subunits. The western ridge, which islocated under the OU2 Treatment System and Sky Harbor International Airport,primarily impacts flow in the B and D subunits.

Groundwater contaminant plumes have been identified in each of the subunits. TCEconcentrations range from approximately 1,000 :g/L near the Honeywell bedrock ridgeto 5 :g/L along the north and south Site boundaries of OU2.

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Hydraulic conductivity values have not been established for each of the three subunits.Several multi-well, long-term aquifer tests have been conducted in OU2, but the testswere generally performed in wells constructed across the entire alluvial aquifer (i.e.,across the subunits). Results of these combined subunit tests are variable, but generallyindicate hydraulic conductivity values from approximately 130 feet per day (ft/day) to340 ft/day in ASE-37A and EW-S, respectively (CH2M Hill, 2005).

The multi-well aquifer test was conducted in TEW-1, which is screened exclusively inthe A subunit, indicated a hydraulic conductivity value of 450 ft/day (CRA, 1999).

In 2005, two short-term single-well aquifer tests were performed in OU2 in an attempt totest the B and D subunits exclusively. The results of these tests are presented in theAddendum to the Construction Completion Report, Results of Additional GroundwaterMonitor Well and Piezometer (NW07-M, NW09-M, NW13-M/D, and NW14-M/D)Installations, 52nd Street Superfund Site, Operable Unit 2 Area, Phoenix, Arizona, datedMarch 27, 2006 and prepared by CRA (Addendum Report). Appendix E of theAddendum Report concluded that based on the aquifer testing results, Unit B has a lowerpermeability than Unit D by approximately an order of magnitude. The average hydraulicconductivity for Unit D is estimated at 16.9 ft/day. For Unit B, the average hydraulicconductivity is 2.40 ft/day.

Although it is not discussed in the conclusions, the well yield observed during the initialstep test in NW11-M was lower than expected. Upon inspection, abundant scaling wasnoted in the well. The well was redeveloped in an attempt to improve the well efficiency,but as noted in the Companies response to EPA’s May 17, 2006 comments (see item #6),the short-term single well response aquifer test specific capacity values for NW-11Mwere lower than expected due to a number of factors including: scale build-up within thewell, well screen and sand pack, and well construction (well screen is 0.020” verticalslots). As such, ADEQ believes there were technical issues with the test and that thehydraulic conductivity values derived from the tests are inconclusive. Long-termmulti-well aquifer tests in subunits B and D are needed to gain a better understanding ofthe OU2 conceptual site model and to facilitate future OU2 analyses.

Remedial Objectives

The remedial objectives are to establish and maintain a capture zone across the entirewidth and depth of the contaminant plume near Interstate 10 and Van Buren Street.

7.1.1.2 Step 2: Define the site-specific Target Capture Zone

The site-specific Target Capture Zone (TCZ) is defined as the entire width and depth ofthe OU2 contaminant plume to the COC specific MCL, primarily TCE, in the vicinity ofInterstate 10 and Van Buren Street. This means that the width of the contaminant plumein each of the subunits (A, B, and D) constitute the TCZ.

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The OU2 interim remedy includes three groundwater extraction wells, EW-N, EW-M,and EW-S. As required under the Amended UAO, these wells were constructed in 2001in accordance with the 100% Remedial Design Report. The wells are 20 inch diameterwith louvered screen intervals constructed from 100-220 feet bgs, 86-206 feet bgs, and94-194 feet bgs in EW-N, EW-M, and EW-S, respectively. The north, middle, and southextractions wells were designed to operate at flow rates of 1,400 gpm, 2,200 gpm, and1,700 gpm, respectively. The total volume of groundwater extracted was shown viagroundwater modeling in the Remedial Design Report (CRA, 1999) to produce a TCZ inexcess of the width of the 1997 OU2 contaminant plume (approximately 6,000 ft).

7.1.1.3 Step 3: Interpret water levels using potentiometric surface maps and water levelpairs

Potentiometric Surface Maps

Groundwater levels have been interpreted for the OU2 remedy in the OU2 GroundwaterMonitoring Reports and Annual Effectiveness Reports. Appendix B includes copies ofthe annual groundwater elevation maps from the 2002, 2003, 2004, and 2005Effectiveness Reports. These figures depict the groundwater elevation contours andzones of capture as interpreted by the Companies. ADEQ and LFR reviewed thegroundwater elevation data and contours depicted on each of these figures. ADEQ andLFR also evaluated the corresponding interpretation of capture depicted on the figuresand evaluated the adequacy of capture with respect to the TCZ. Review of these figuresindicates the following:

2001

2001 Effectiveness Report Figure 2.1 depicts baseline OU2 remedy conditions. TheSeptember 2001 groundwater elevation contours interpreted by the Companies depictsouthwest changing to westerly groundwater flow in pre-pumping conditions. No capturezone is depicted since the data predates OU2 system operations. No comment regardingcapture or the TCZ is applicable to this Figure.

2002

2002 Effectiveness Report Figure 2.3 depicts the September 2002 groundwater elevationcontours following one year of groundwater extraction at the OU2 system. Because thecurrent level of understanding of the conceptual site model and the hydrostratigraphicsubunits A, B, and D was not incorporated into the annual effectiveness reports until2005, the alluvial groundwater elevations and groundwater contours are depicted on asingle figure. Northwest deflection of the south side of the 1,010 ft contour is interpretedin the Figure; however, groundwater elevation data was not available for thesouthern-most well in the area, AS-02. Groundwater elevation data supporting the 1,015and 1,005 contours from wells ASE-36A and AA-MW-2 indicate that flow is generallywest, and not northwest. It is reasonable to assume that the 1,010 contour should be

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drawn similar to the 1,015 and 1,005 ft contours. Changing the 1,010 contour wouldresult in generally western flow along the south side of the OU2 plume. Thisinterpretation indicates that the TCZ may not have been fully achieved by the OU2system in September 2002.

2003

2003 Effectiveness Report Figure 3.7 depicts the September 2003 groundwater elevationcontours. Like the September 2002 data, the lack of groundwater elevation data south ofEW-06 inhibits interpretation of the contours. As a result, interpretation of the south zoneof capture is questionable. Conservative interpretation of these contours indicates that theTCZ may not have been fully achieved by the OU2 system in September 2003.

2004

2004 Effectiveness Report Figures 3.10 and 3.11 depict the September 2004 groundwaterelevation contours as interpreted for the Salt River Gravel and Basin Fill, respectively.The Salt River Gravel contours again suffer from a lack of groundwater elevation datasouth of EW-06 compromising interpretation of both the contours and the zone ofcapture. The Basin Fill contours indicate that the TCZ was not achieved along the southside of the plume.

2005

2005 Effectiveness Report Figures 3.8 and 3.9 depict the September 2005 groundwaterelevation contours as interpreted for the A+ B and D subunits, respectively. The lack ofA or B subunit groundwater elevation data south of the plume boundary in the vicinity ofInterstate 10 inhibits effective interpretation of the groundwater elevation contours.Conservative interpretation of these contours indicates that the TCZ may not have beenfully achieved by the OU2 system in September 2005. The D subunit groundwaterelevation contours on 2005 Effectiveness Report Figure 3.9 indicate that the TCZ was notfully achieved along the south side of the plume.

It is noted that Honeywell data located to the east of the system indicates rotation ofgroundwater gradient to the northwest along the south side of the plume. Review of thesedata indicate that the 2005 Salt River flow event impacted the area with local rechargefrom the river causing a temporary shift from west to northwest groundwater flow. Theflow event appears to have facilitated improved capture along the south side of the OU2plume in 2005. As the impact of the flow events subside, groundwater gradients areexpected to return to conditions similar to the first three years of operation.

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Flow Net Analysis

2004

In addition to the groundwater elevation maps in the Effectiveness Reports, theCompanies completed capture zone calculations for the OU2 system. The results arereported in Capture Zone Calculations – Operable Unit 2, 52nd Street Superfund Site –Phoenix, Arizona (Capture Letter) dated May 28, 2004 and prepared by CRA (seeAppendix C). Three evaluations were performed for the Capture Letter: a flow netanalysis, a theoretical capture zone analysis, and chemical concentration trends wereanalyzed. The flow net analysis is discussed below; the other analyses are discussedunder Steps 4 and 5 below.

The flow net analysis was performed by manually producing groundwater elevationcontours and streamlines for the Salt River Gravels and Basin Fill (A and B subunits).The resulting flow nets are depicted on Figures 3a and 3b of the Capture Letter. TheLetter concludes that the southern capture boundary extends beyond EW-06 to the southand that the capture zones are similar for the Salt River Gravels and Basin Fill.

As discussed under Potentiometric Surface Maps, above, limited subunit A and Bgroundwater elevation data south of EW-06 makes interpretation of the groundwaterelevation contours difficult. Conservative interpretation of the available elevation dataindicates that the TCZ may not be fully achieved along the south boundary. Figure 3bindicates that the TCZ was not achieved along the southern boundary, as the extent ofcontamination in subunit B is farther south, between NW11-M and NW09-M (seeAppendix C).

2005

A flow net analysis was also included in Appendix A of the 2005 Effectiveness Report(see Appendix C). Figures A. 1 and A. 2 depict the hand-drawn flow paths andgroundwater contours based on groundwater elevation data collected in January 2006.These data include water elevations from new groundwater monitor wells NW09-M,NW13-M, and NW14-M.

Review of Figure A. 1 indicates that the groundwater elevation reported for wellsNW05-S and NW06-S (1,006.10 ft and 1,006.45 ft, respectively) do not appear to havebeen incorporated into the groundwater contours. As depicted in the Figure, the 1,006 ftcontour along the south side of the plume has a southwest-northeast orientation. Asdrawn, this contour seems to support capture of the plume in the A and B subunit to thesouth; however, incorporating the data discussed above would change the 1,006 ftcontour and the flow paths. Employing a conservative interpretation using the data, the1,006 ft contour would likely have a more north-south orientation from the area ofNW06-S to the area of NW13-M. Corresponding flow paths along the south side of theplume in both the A and B subunits would be oriented generally east to west, indicatinginadequate capture. Conservative interpretation of recent groundwater elevation dataindicates that the TCZ was not achieved along the southern boundary.

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Water Level Pairs

Analysis of water level pairs is also recommended in EPA’s 2002 Elements for EffectiveManagement of Operating Pump and Treat Systems. Comparison of groundwaterelevations at two or more monitor well locations oriented perpendicular to the TCZ mayprovide an additional line of evidence to evaluate capture.

Analysis of water level pairs was not included in the Effectiveness Reports. In an effortto evaluate this potential line of evidence, a review was performed of water level pairs forthe five year review based on the September 2005 Effectiveness Report data. The waterlevel pair analysis is summarized below:

Subunits A and B

Review of the most recent groundwater elevation map in the 2005 Effectiveness Reportfor the A and B subunits (Figure 3.8 of the 2005 Effectiveness Report) indicates that fewwell pairs exist which are perpendicular to the zone of capture; however, several wellpairs are sufficiently oriented to analyze water level pairs. These wells are highlighted onthe Figure 3.8 (see Appendix B) and include:

• CRA-01 and EW-07 • NW-04S and NW-02 • NW-04S and NW-05S • NW-05S and NW-02 • NW-05S and NW-03 • NW-06S and NW-03 • NW-07S and NW-06S • NW-07S and EW-06 • EW-06 and EWSPZ1

Review of the groundwater elevations for the north water level pairs generally indicatesinward flow. These data provide supporting evidence that the TCZ is being achievedalong the north side of the OU2 plume in the A and B subunits.

Analysis of water level pairs on the south side of the TCZ is problematic due to limitedgroundwater elevation data. Inward flow is indicated by well pairs EW-06 and EWSPZ1,indicating that the zone of capture may exist as far south as EW-06; however, noadditional A or B well data is reported to the south or southwest of EW-06. It should alsobe noted that EWSPZ1 is screened across all three subunits and limits the applicability ofthis water level pair for capture zone analysis of the A and B subunits. Based on theavailable data, water level pair analysis along the south side of the TCZ does not providesupporting evidence for adequate capture.

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Subunit D

Review of the most recent groundwater elevation map in the 2005 Effectiveness Reportfor the D subunit (Figure 3.9) indicates that very few well pairs exist to perform waterlevel pair analysis. Potential well pairs for subunit D include:

• NW-12D and OU3-14D • NW-07D and NW-11D • NW-11D and NW-09D • NW-09D and NW-10D

Comparison of NW-12D and OU3-14D, which are located near the north side of theTCZ, is problematic because the wells are not located perpendicular to the zone ofcapture. Evidence to support capture can not be determined from this water level pair.

Comparison of the water levels between NW-09D and NW-10D indicates that somedegree of inward flow occurs as far south as NW-10D; however, outward flow isindicated by water levels collected from NW-07D and NW-11D. These data show thatwhile some inward flow is occurring along the south side of the OU2 plume in the Dsubunit, capture of the southern boundary of the plume is not confirmed. Analysis ofthese water level pairs in the D subunit provides little evidence to evaluate capture of thesouth side of the D subunit plume.

7.1.1.4 Step 4: Perform calculations (if appropriate based on site complexity)

Theoretical Capture Zone Analysis

2004

The theoretical capture zone analysis was performed by simulating the OU2 system usinga RESSQ computer simulation, a semi-analytical solution developed by Javandel, et al.(1984). Two simulations were performed: one for the Salt River Gravel and one for theBasin Fill. Input parameters were provided for each simulation; however, littleinformation was provided regarding the selected extraction rates within each of thesubunits and no discussion was provided regarding sensitivity analysis.

Figures 4 and 5 of the Capture Letter depict the results of these simulations. The figuresdepict a wide zone of capture in both subunits. The simulated zone of capture appears torealistically represent conditions to the north, but capture to the south appears to besignificantly greater than observed (compare with Figures 3a and 3b). The difference insimulated and observed capture indicates that the theoretical capture zone is flawed.Initial orientation of the RESSQ grid or aquifer heterogeneities and/or anisotropy may bethe cause of the difference in capture. As provided in the Capture Letter, the theoreticalcapture zone analysis does not provide evidence to support adequate capture.

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2006

Another capture zone evaluation was also performed as part of the 2005 EffectivenessReport (CRA, 2006b). The evaluation is included in Appendix A of the EffectivenessReport (see Appendix C). A theoretical capture zone analysis was performed in a mannersimilar to the analysis performed in the Capture Letter discussed above; however, threescenarios instead of two were run for the Effectiveness Report. Again, input parameterswere provided for each of the simulations; however, little information was providedregarding the selected extraction rates within each subunit and no discussion wasprovided regarding sensitivity analysis.

It should be noted that an extraction rate of 10.5 gpm was selected for EW-S yet the Dsubunit was not observed in soil core from this location. The model may have been morerealistically run with no extraction in subunit D at EW-S.

Figures A. 3, A. 4, and A. 5 of Appendix A depict the results of the three simulationssuperimposed over the subunit plume boundaries. Like the 2004 Capture Letter, thefigures depict a wide zone of capture in each of the three subunits. Comparison with thehand-contoured flow paths depicted on Figures A. 1 and A. 2 indicate some similaritiesalong the north side of the plume but simulated capture to the south appears to besignificantly greater than observed. The difference in simulated and observed captureindicates that the theoretical capture zone is flawed. Contrary to the conclusions set forthin Appendix A of the 2005 Effectiveness Report, the theoretical capture zone analysisdoes not calibrate with actual site data and therefore can not be used as evidence tosupport adequate capture.

7.1.1.5 Step 5: Evaluate concentration trends

Groundwater Chemistry Changes

The Annual Effectiveness reports and the 2004 and 2006 capture zone analyses includedan evaluation of concentration trends in groundwater chemistry by plotting and reviewingconcentrations trends for selected wells in the OU2 system network. The concentrationsversus time graphs included in Appendix E depict concentrations collected from 2001 to2004. Selected wells included 16 A subunit wells and 9 B/D subunit wells. Because thetrends do not include data prior to the baseline sampling event, it is difficult to determineif the decline observed in the wells is due to the operation of the OU2 system or anexisting trend in the OU2 plume.

Concentration trends were plotted for two wells: EW-06 located near the southern side ofthe OU2 plume at 20th Street and EW-07 located near the northern side of the OU2plume at 20th Street. These data are shown on graphs included at the end of Appendix Eof this five year review.

EW-07 rapidly decreased from 14 :g/L in the baseline sample to below detection limitsafter one year of operation in the September 2002 sample and has remained below

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detection limits since. Concentration trends in wells located along the southern boundaryof the TCZ are less clear. EW-06 indicates a declining trend since 2001; however,concentrations increased from 6.8 :g/L in September 2004 to 22 :g/L in September2005. It should be noted that both of the graphs show that a declining trend was observedin the wells prior to system start-up. The TCE trend for EW-07 is more consistent andprovides some supporting evidence for capture to the north. The trend in EW-06 is notconclusive and does not provide supporting evidence for capture along the south side ofthe TCZ.

7.1.1.6 Step 6: Interpret actual capture based on Steps 1-5, compare to target capturezone, and assess uncertainties and data gaps

The 2002, 2003, 2004, and 2005 Annual Effectiveness Reports and supplemental capturezone analyses performed in 2004 and 2006 all generally conclude that the OU2groundwater extraction system is containing the full width and depth of the groundwaterplume.

Based on a review of the data conducted in Steps 1 though 5, it appears that the OU2system is meeting the remedial objectives with respect to plume capture on the north sideof OU2; however, based on a conservative interpretation of the data, it appears that thesouth side of the plume is not fully captured. More specifically, capture in subunit A isquestionable, capture in subunit B is likely inadequate, and capture in subunit D isinadequate.

Because data are lacking in all three subunits along the south side of the TCZ, someuncertainty exists in the interpretation. Less uncertainty exists to the north. Alternativeinterpretations of capture are possible; they are related to alternative interpretation ofgroundwater elevation contours along the south side of the TCZ. Conclusions derivedfrom capture calculations and concentration trends provide little support for thealternative interpretations. Additional data are needed to address the northern, southern,and the downgradient TCZ in each of the three subunits.

7.1.2 System Operations/O&M

In general, the OU2 groundwater treatment system was in excellent condition andoperating within specified ranges. No other significant or minor issues were noted duringthe inspection.

Extracted groundwater is treated at the treatment plant and transferred to SRP’s GrandCanal for irrigation use providing a beneficial end use for the water. Treatment plantinfluent and effluent data are collected on a monthly basis. The effluent results werecompared to the requirements of the ROD and ESD. Based on the data reviewed, thetreated effluent met the requirements of the ROD and ESD.

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7.1.3 Costs of System Operations/O&M

A discussion of the annual O&M costs was included in Section 4.3. The costs for 2001reflect the start-up and commissioning of the OU2 system, 2002 costs reflect the first fullyear of operation of the treatment system, and from 2002 to 2005 costs were generallyconsistent, but below the anticipated annual costs of $1,640,000. This suggests that thetreatment system is operating below expectations, which is likely due to the decreasedextraction rate from EW-S.

7.1.4 Monitoring Activities

Capture and containment can only be confirmed with an adequate monitor well networkthat provides both groundwater level data to demonstrate hydraulic capture andgroundwater quality data to demonstrate overall reduction of mass within and outside thecapture zone(s). A review of the existing monitor well network indicated several areaswhere lack of data hinders the evaluation of the effectiveness of the remedy. Additionalalluvial monitor wells are needed in all three subunits to the north, south, anddowngradient of the treatment system to evaluate capture of the TCZ.

7.1.5 Opportunities for Optimization

No opportunities for treatment system optimization were identified during this review.

7.1.6 Early Indicators or Potential Remedy Problems

EW-S groundwater extraction rates have declined. The well was designed to operate at1,700 gpm. The initial extraction rate for the well was approximately 800 gpm and hasdeclined to the current extraction rate of approximately 200 gpm. It is not believed thatconstruction is an issue for this well; rather, EW-S is located near the airport bedrockridge and is screened in finer grained materials than the other extraction wells.Nonetheless, if the rate declines further in the future, capture to the south may also bereduced, further aggravating effectiveness of the remedy.

The groundwater elevation maps from the first four years of operation of the OU2 systemindicate that the majority of the groundwater entering the system originates from thenortheast portion of OU2. This may lead to a lower than expected impact on the southside of OU2, especially in the stagnation zone on the downgradient side of the Honeywellbedrock ridge.

Reduced effectiveness of cleanup on the upgradient Honeywell bedrock ridge stagnationzone is also expected, as concentrations in those wells have shown minimal change.

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7.1.7 Implementation of Institutional Controls and Other Measures

Institutional controls have been implemented by ADEQ regarding access to contaminatedgroundwater. Since WQARF was revised in 1997, ADEQ and ADWR have developed aprocedure whereby ADWR notifies ADEQ when a NOI to Drill a Monitor Well withinthe Motorola 52nd Street Superfund Site has been filed. ADEQ can then notify theproperty owner of the risk involved with using the groundwater.

7.2 Question B: Are the exposure assumptions, toxicity data, cleanup levels, andremedial action objectives (RAOs) used at the time of the remedy selectionstill valid?

7.2.1 Changes in Standards and To Be Considered

OU2 is currently in compliance with the ARARs established in the ROD and ESD(Tables 5 and 6). No chemical-specific soil or groundwater clean-up levels wereestablished in the ROD and ESD. However, the remedy does require that treatedgroundwater effluent meet drinking water standards with no exceedances of the MCLs.

There are no newly promulgated standards or revisions to the ARARs that would call intoquestion the protectiveness of the remedy. However, new ARARs and TBCs are likely tobe determined for the final remedy for OU2.

7.2.2 Changes in Exposure Pathways, Toxicity, and Other Contaminant Characteristics

Land use at the site has remained relatively the same and no new human health orecological routes of exposure have been identified.

Since the 1992 health evaluation, there have been a number of changes to the toxicityvalues for certain COCs at the Site (Table 7). Revisions to the toxicity values for1,1-DCE and vinyl chloride indicate a lower risk from exposure to these chemicals thatwere previously considered. On the other hand, evaluation of the toxicity values for PCEand TCE is ongoing and may indicate higher risks from exposure than previouslyconsidered.

The greatest uncertainty with toxicological changes for the Site is associated with TCE.In August 2001, U.S. EPA’s Office of Research and Development (ORD) released thedraft Trichloroethylene Health Risk Assessment: Synthesis and Characterization (TCEHealth Risk Assessment) for external peer review. The draft TCE Health RiskAssessment takes into account recent scientific studies of the health risks posed by TCE.According to the draft TCE Health Risk Assessment, for those who have increasedsusceptibility and/or higher background exposures, TCE could pose a higher risk throughinhalation than previously considered. The draft TCE Health Risk Assessment isavailable on-line at: http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=23249.

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The Science Advisory Board, a team of outside experts convened by EPA, reviewed thedraft TCE Health Risk Assessment in 2002. The Science Advisory Board’s review of thedraft TCE Health Risk Assessment is available at: http://www.epa.gov/sab/pdf/ehc03002.pdf.

In July 2006, the National Academy of Sciences completed additional peer review ofscientific issues that were the basis for the draft TCE Health Risk Assessment. Inresponse to this review, EPA will revise the draft TCE Health Risk Assessment.Consequently, review of the toxicity value for TCE may continue for a number of years.This issue will need to be updated in subsequent five-year reviews.

In addition, a Health Based Guidance Level (HBGL) and Preliminary Remediation Goal(PRG) have been established for 1,4-dioxane. This contaminant has been detected at theSite at elevated concentrations and should be addressed in the final remedy.

As discussed in Section 6.4.1, elevated levels of metals above SRLs and GPLs have beendetected at the Papago Plating Facility (located upgradient from the OU2 GWTP) andabove MCLs in groundwater downgradient of the Facility indicating the potential for acontinued threat to the groundwater and to the OU2 GWTP. It is recommended thatgroundwater samples be evaluated periodically for the presence of metals.

7.2.3 Changes in Risk Assessment Methods

The1992 risk assessment methodology used was based on EPA Risk AssessmentGuidance for Superfund, Volume I, Human Health Evaluation Manual: Part A (EPA,1989). Current methodology for risk assessment has not changed, however, the air modelused to estimate indoor risks has changed and it would be prudent to model current risksbased on this newer model (EPA Draft Guidance for Evaluating the Vapor Intrusion toIndoor Air Pathway From Groundwater and Soils, November 2002) and updated toxicityvalues. ADEQ is currently evaluating the methodology for evaluating the indoor air risksand will implement the methodology once the guidance is finalized or EPA and ADEQagree to the process for evaluating the pathway.

7.2.4 Progress Towards Meeting RAOs

The RAOs provided in the ROD and ESD were selected to set goals for an interimgroundwater remedy designed to contain and reduce groundwater contamination. Nochemical-specific groundwater clean-up levels were established in the ROD and ESD.The interim groundwater remedy is generally meeting these goals; however, issuesregarding the containment of groundwater contamination have been raised (see Section7.1.1).

7.3 Question C: Has any other information come to light that could call intoquestion the protectiveness of the remedy?

No other information has come to light that would call into question the protectiveness ofthe remedy.

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7.4 Summary of Technical Assessment

According to the data reviewed, the site inspection, and the interviews, ADEQ hasidentified several concerns that call into question the effectiveness of the remedy.Because data are lacking in all three subunits along the north and south side of the TCZ,some uncertainty exists in the interpretation. It appears that the OU2 system is meetingthe remedial action objectives with respect to plume capture on the north side of OU2;however, based on a conservative interpretation of the data, it appears that the south sideof the plume is not fully captured. More specifically, capture in subunit A isquestionable, capture in subunit B is likely inadequate, and capture in subunit D isinadequate. Additional data are needed to address the northern, southern, and thedowngradient TCZ in each of the three subunits.

The OU2 groundwater treatment system was in excellent condition and operating withinspecified ranges. No significant issues were noted during the inspection. The extractedgroundwater is treated and then transferred to SRP’s Grand Canal for irrigation useproviding a beneficial end use for the water. Treatment plant influent and effluent dataare collected on a monthly basis. Based on the data reviewed, the treated effluent met therequirements of the ROD and ESD.

Changes to toxicity factors of certain COCs have occurred and should be evaluated. Inaddition, new methodology to evaluate indoor air risks is being developed. While nochemical-specific groundwater clean-up levels were established in the ROD and ESD,new chemical-specific ARARs and TBCs are likely to be determined for the final remedyfor OU2.

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8.0 ISSUES

The following issues discovered during the five-year review are discussed below and areincluded in Table 8.

8.1 Groundwater Issues

Several issues were identified during the technical assessment of the OU2 interimremedy. These issues are primarily associated with groundwater capture. The followingis a list of the issues.

8.1.1 Capture Issues

1) Little to no groundwater elevation and quality data are available in any of thesubunits along the north side of the OU2 plume. As a result, the impact of theOU2 treatment system can not be adequately evaluated in that area. Additionalmonitor wells are needed along the north side of the OU2 plume in each of thesubunits to evaluate the OU2 capture effectiveness.

2) Groundwater elevation and quality data are lacking in all three subunits along thesouth side of the OU2 plume. As a result, the impact of the OU2 treatment systemis difficult to assess in this area. Additional monitor wells are needed along thesouth side of the OU2 plume in each of the subunits to evaluate the OU2 captureeffectiveness.

3) Additional groundwater elevation and quality data are needed downgradient ofthe OU2 treatment system to evaluate capture in the D subunit. Additionalmonitor wells are needed in the D subunit downgradient of the OU2 treatmentsystem to evaluate capture in subunit D.

4) Although capture appeared more effective in 2005, it appears to be related to anorthwest rotation of groundwater gradients due to recharge from the Salt Riverflow event. However, based on a conservative interpretation of the data, usingconverging lines of evidence, it appears the TCZ along the south side of theplume is not fully captured.

8.1.2 Future Issues

5) EW-S groundwater extraction rates have declined. The well was designed tooperate at 1,700 gpm. The initial extraction rate for the well was approximately800 gpm and has declined to the current extraction rate of approximately 200gpm. If the rate declines further in the future, capture to the south may also bereduced.

6) Future containment of the D subunit is problematic because: (1) the D subunit isprimarily contaminated in the south portion of OU2, (2) EW-S does not penetrate

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the D subunit and therefore does not directly extract from the D subunit, and (3)capture is currently questionable and may decrease if EW-S extraction ratescontinue to decline.

7) The Agencies are concerned that the stagnation zone on the upgradient anddowngradient side of the Honeywell bedrock ridge is not being addressed by theOU2 system.

8) Long-term multi-well aquifer tests in subunits B and D are needed to gain a betterunderstanding of the OU2 conceptual site model and to facilitate future OU2analyses.

9) The OU2 system is an interim remedy and therefore a final remedy for OU2 mustbe developed. The final remedy will address the issues identified in this five-yearreview and must consider and integrate the Honeywell light nonaqueous phaseliquid (LNAPL) remedy.

8.2 Health Assessment Issues

The following issues were discovered during the five-year review.

10) Changes to the toxicity levels for certain contaminants have occurred since thelast five-year review.

11) New methodology is being developed for indoor air risk evaluation. Once themethodology is finalized or EPA and ADEQ can agree to the process forevaluating the pathway, an indoor air risk evaluation should be performed for theOU2 Area.

12) Boron has been detected in influent and effluent samples from the treatment plant.

8.3 General Issues

The following general issues are noted:

13) The 2005 Effectiveness Report is not consistent with respect to the lithologic andhydrogeologic representation and interpretation of the D subunit. Cross sectionFigure 2.6 does not include the interpretation of bedrock or the D subunit on theeast portion of the cross-section. Figure 3.9 does not depict the area where the Dsubunit is pinched-out by the OU2 bedrock ridge. Consistent interpretation of thehydrostratigraphic subunits and available data is needed for OU2 analyses (e.g.,interpretation of subunit D as both unconfined and semiconfined). Additionally,consistent use of available data is needed for OU2 analyses (e.g., D subunitgroundwater elevations along the north side of OU2).

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9.0 FOLLOW-UP ACTIONS AND RECOMMENDATIONS

Based on the issues identified during the five-year review process, the followingcorrective actions should be taken. Table 9 provides a summary of the follow-up actionsand recommendations listed below along with the responsible party, oversight agency,and schedule for completion.

9.1 Follow-up Actions

The following actions regarding the groundwater issues at the OU2 Area should beaddressed.

9.1.1 Groundwater Follow-up Actions

9.1.1.1 Groundwater Capture Follow-up Actions

1) A work plan should be prepared and submitted to ADEQ to address the data gapsalong the north side of the OU2 plume. The work plan should include theinstallation of monitor wells in each of the three alluvial subunits.

2) A work plan should be prepared and submitted to ADEQ to address the data gapsalong the south side of the OU2 plume. The work plan should include theinstallation of monitor wells in each of the three alluvial subunits.

3) A work plan should be prepared and submitted to ADEQ to address the data gapsdowngradient of the OU2 treatment system. The work plan should include theinstallation of monitor wells in the D subunit.

4) Future capture evaluations shall consider the following when examining multiplelines of evidence:

• conservative interpretation of groundwater elevation data when producinggroundwater elevation contours, especially in areas where data arelacking;

• analysis of water level pairs for appropriately configured monitor wells;

• capture zone calculations that are conceptually consistent with site dataand interpretation. The method(s) used to calculate the capture zoneshould be discussed by the appropriate representatives from theCompanies and the Agencies; the final methodology will be approved bythe Agencies. Capture zone calculations must consider site lithology andhydrogeology and address the potential impact of simplifying site data ininterpretation. Capture zone calculation should also incorporate sensitivityanalyses; and

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• concentration trend analysis shall include all historic data. Analysis oftrends shall consider the impact of fluctuations in groundwater levels,changes in groundwater gradient, and the conceptual site model.

9.1.1.2 Future Groundwater Issues Follow-up Actions

5) The Companies should continue to monitor the extraction rates for EW-S.

6) The Companies should develop a plan to monitor groundwater capture along thesouthern boundary, particularly in subunit D.

7) The Companies should prepare a plan to evaluate the effectiveness of the OU2treatment system on the stagnation zones upgradient and downgradient of theHoneywell bedrock ridge.

8) The Companies should develop a plan to conduct long-term multi-well aquifertests in subunits B and D. The data obtained from these tests will be useful fordesigning a final remedy for OU2.

9) A final remedy will need to be developed for OU2 that incorporates theHoneywell LNAPL remedy.

9.1.2 Health Assessment Follow-up Actions

The following actions regarding health assessment issues at the OU2 Area shouldaddressed.

10) A review of the toxicity values for COCs at the Site should be conducted beforethe final remedy is selected.

11) New methodology is being developed for indoor air risk evaluation. Once themethodology is finalized or EPA and ADEQ can agree to the process forevaluating the pathway, an indoor air risk evaluation should be performed for theOU2 Area.

12) Effluent samples should be collected and analyzed for boron. If the results areabove the surface water limit for agricultural irrigation, SRP should be notified.

9.1.3 General Follow-up Actions

The following actions regarding general issues at the OU2 Area should be addressed.

13) The Agencies recommend a technical work group meeting to discuss and addressgroundwater elevation and quality data, capture issues, and hydrostratigraphicissues.

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9.2 Parties Responsible for Implementation

The Companies, as identified in the Amended UAO and supporting decision documents,are responsible for the recommended actions.

9.3 Agencies with Oversight Authority

The EPA is the current agency with oversight authority. ADEQ and the Companies arecurrently negotiating an agreement whereby ADEQ will assume oversight authority.

9.4 Schedule for Completion

Because the OU2 interim remedy issues identified above are current and ongoing, therecommended actions under Section 9.1 should be conducted as soon as practical. Table9 outlines the expected completion date.

Page 46

LFR Inc.

10.0 PROTECTIVENESS STATEMENT

A protectiveness determination of the OU2 interim remedy cannot be made at this timeuntil further information is obtained. The necessary follow-up actions andrecommendations identified in this Report are needed to evaluate protectiveness. Theactions will require the efforts of the Companies and the Agencies to be completed. It isexpected that these actions will take approximately 1 year to complete at which time aprotectiveness determination will be made.

Page 47

LFR Inc.

11.0 NEXT REVIEW

The next review for the Site is required within five years of EPA’s signature of thisreview. It is anticipated that the next review will be completed by the end of September2011.

Page 48

TABLES

Table 1 - Chronology of Events at the OU2 AreaMotorola 52nd Street Superfund Site

Phoenix, ArizonaDate Event

1985-1989 ADEQ conducted a Remedial Investigation and initiated an investigation of potentially responsible parties (PRP's).

1987 The East Washington area was listed on ADEQ's Water Quality Assurance Revolving Fund (WQARF) Priority List.

July 1988Questionnaires mailed to 995 facilities located in the East Washington area requesting information regarding their hazardous substance use, storage, and disposal practices.

August 1989 ADEQ completed the Phase I Report for the East Washington area, which was made available for public review.

1990-1992ADEQ and Freescale continued an area-wide groundwater investigation to define the extent of groundwater contamination in the OU2 area. Approximately 48 monitor wells with 120 sampling ports were installed and over 300 aquifer tests were conducted.

1992 ADEQ and EPA developed a second operable unit (OU2) study area to address groundwater contamination and a final remedy.

1992Freescale submitted the Remedial Investigation Report to ADEQ confirming that contamination was migrating from the Motorola facility and into the East Washington area.

1992 ADHS completed a Baseline Risk Assessment concluding no imminent health hazard.

1992 EPA named additional potentially responsible parties: Honeywell, ITT Cannon, and Tiernay Turbines (now Walker Power Systems).

February 1992 Freescale submitted the Final Remedy Remedial Investigation Report to ADEQ.June 8, 1992 Freescale submitted the Response to Comments on Final Remedy Remedial

Investigation Report to the EPA.July 15, 1992 Freescale submitted a Pre-Design Remedial Investigation Work Plan.August 3, 1992 Freescale submitted the Addendum to the Pre-Design Remedial Investigation Work

Plan.November 1992 ADHS submitted the Baseline Risk Assessment to ADEQ.November 1992 Center for Environmental Health Studies submitted the Critique of the Baseline Risk

Assessment to ADHS.

1993ADEQ discovered groundwater contamination (TCE) in the area beyond the Old Cross Cut Canal thought to be a part of the East Washington Area, a separate contaminant plume.

1993 EPA named the City of Phoenix a Potentially Responsible Party.

1993Freescale issued a series of reports documenting the development and calibration of a flow and transport model that was used for the evaluation of remedial alternatives in the area from 46th Street to approximately 24th Street between McDowell and Buckeye Roads.

1993 ATSDR completed an update to the 1988 Health Assessment.March-August 1993 ADEQ and EPA determined that this would be a second interim remedy (OU2).March 1993 Freescale submitted a Draft Detailed Analysis of Alternatives for the final remedy.August 1993 Freescale submitted a Draft Interim Remedy Feasibility Study Report to ADEQ.October 1, 1993 Freescale submitted an updated Interim Remedy Feasibility Study Report to ADEQ.October 1993 Freescale submitted an updated Interim Remedy Feasibility Study Report to ADEQ.November 9, 1993 Freescale submitted the Interim Remedy Feasibility Study Report to ADEQ.December 1993 Freescale submitted the Supplement to Interim Remedy Feasibility Study Report to

ADEQ.

Page 1 of 5

Table 1 - Chronology of Events at the OU2 AreaMotorola 52nd Street Superfund Site

Phoenix, ArizonaDate Event

December 1993 ADEQ and EPA issued a proposed groundwater remedy for public review and comment.

1994 ADEQ requested Honeywell, ITT Cannon, the City of Phoenix, and Freescale to implement the groundwater remedy.

January 1994 ADEQ approved the updated Interim Remedy Feasibility Study Report submitted by Freescale.

February 1994 Freescale submitted a Hydrogeologic Investigation of Subsurface Bedrock Conditions Report of the East Washington area WQARF Site.

February 9, 1994 Public meeting held to take oral comment from the public regarding the OU2 Feasibility Study.

July 21, 1994 The EPA submitted the Record of Decision Operable Unit 2 East Phoenix Groundwater Containment.

November 1994 Freescale submitted a letter with results of additional drilling conducted to confirm the depth to bedrock

1995 ADEQ issued a No Further Action letter to ITT Cannon.1996 ATSDR completed an update to the 1988 Health Assessment and the 1993 update

to the Health Assessment.February 1996 Freescale submitted M152 Model Documentation Report to ADEQ.

February 1996Freescale submitted the MI52 Model Documentation Report presenting models of predicted groundwater flow and contaminant transport of VOCs from Freescale and other sources.

October 1, 1996 Freescale and the City of Phoenix signed a Consent Decree with ADEQ to implement the design of a groundwater containment and treatment system for OU2. Honeywell withdrew from the agreement and did not participate in the design.

1997 ADEQ and EPA determined that the investigation of groundwater contamination from 52nd Street would continue to 7th Avenue under the federal Superfund program.

January 1997 Honeywell submitted the Honeywell Preliminary Analysis of Freescale Model to ADEQ.

March 1997 The Companies submitted the Remedial Design Work Plan Operable Unit 2 to ADEQ.

October 1997 The Companies submitted the Preliminary (30%) Design Report Operable Unit 2 Area to ADEQ.

September 18, 1998 The Companies submitted the Pre-Final (90%) Design Report Operable Unit 2 Area to ADEQ.

November 1998 Environmental Simulations Inc. submitted the Groundwater Modeling of the OU2 Recovery System to Honeywell.

November 10, 1998EPA issued a Unilateral Administrative Order (UAO) to The Companies for construction, start-up, and two years of operation and maintenance of the groundwater treatment system.

July 1999 The Final 100% Design Report Operable Unit 2, Motorola 52nd Street Superfund Site.

September 30, 1999 EPA issued the Explanation of Significant Differences to Operable Unit 2 Record of Decision.

November 1999 The Companies submitted the Remedial Action Work Plan Operable Unit 2 Area.March 2000 Construction of the treatment system began.May 2000 EPA submitted Comments to Draft and Final Remedial Action Work Plans to

Freescale and Honeywell.March 2001 IT Corporation submitted the Summary of Preliminary Groundwater Flow and

Contaminant Transport Simulations to EPA.

Page 2 of 5

Table 1 - Chronology of Events at the OU2 AreaMotorola 52nd Street Superfund Site

Phoenix, ArizonaDate Event

July 11, 2001 The Arbitrator's Final Decision and Findings of Fact and Conclusions of Law were submitted to the Companies.

September 24, 2001 Construction Completion Notification was provided to the EPA.September 26, 2001 Pre-Final construction inspection was conducted by ADEQ and EPA.September 28, 2001 EPA issued the Five Year Review Report First Five Year Review Report.October 23, 2001 Final construction inspection was conducted by ADEQ and EPA.December 6, 2001 The Companies submitted the Construction Completion Report.December 13, 2001 The OU2 groundwater treatment system became fully operational, designed to pump

at a rate of approximately 5,000 gallons per minute.January 2002 The Companies submitted the Start Up Report 20th Street Groundwater Treatment

Facility to EPA.January 24, 2002 The Companies submitted the Operation and Maintenance Manual.February 6, 2002 Updates and revisions to the Operation and Maintenance Manual were submitted.May 2002 Freescale conducted an additional investigation of the bedrock ridge area and

submitted a report of the results.May 11, 2002 Updates and revisions to the Operation and Maintenance Manual were submitted.June 7, 2002 The Companies submitted the Revised Tables and Figures July through November

2001 Baseline Monitoring Report OU2 to EPA.July 13, 2002 Updates and revisions to the Operation and Maintenance Manual were submitted.August 29, 2002 The Companies submitted the Results of Hydrogeological and Construction Services

for Installation of Extraction and Monitor Wells to Honeywell, Freescale.October 18, 2002 The Companies submitted the Groundwater Extraction System Adjustments OU2 to

EPA.November 2002 The OU2 groundwater treatment system's pumping rate was reduced to 2,650 gpm.November 5, 2002 Freescale submitted the Evaluation of Groundwater Extraction Rates OU2 Remedy

to EPA.December 24, 2002 The Companies submitted the Proposal/Concurrence to Install Additional

Groundwater Monitoring Wells OU2 to EPA.

February 28, 2003The Companies submitted a Revised Proposal to Install Additional Groundwater Monitoring Wells and Responses to February 7th EPA Comment on the December 24, 2002 Proposal to Install Additional Monitoring Wells.

March 27, 2003 The Companies submitted an Addendum to Revised Proposal to Install Additional Monitor Wells dated February 28, 2003.

April 2003 The Companies submitted the Effectiveness Report 2002, 20th Street Groundwater Treatment Facility.

April 4, 2003 EPA approved the revised proposal to install 11 groundwater monitoring wells.April 10, 2003 The Companies submitted the Draft Remedial Action Report for Motorola 52nd

Street Superfund Site Operable Unit 2.April 10, 2003 The Companies submitted the Remedial Action Report.April 11, 2003 The Companies submitted the Revised 2002 OU2 Annual Effectiveness Report.

May 15, 2003The Companies submitted a clarification letter to the revised proposal dated February 28, 2003 to install eight additional groundwater monitoring wells at four locations.

June -July 2003 The Companies installed 11 additional monitoring wells to provide more data to assess groundwater capture of the treatment system.

September 12, 2003 The Companies submitted Results of Additional Monitoring Well Installations.

Page 3 of 5

Table 1 - Chronology of Events at the OU2 AreaMotorola 52nd Street Superfund Site

Phoenix, ArizonaDate Event

November 2003The combined extraction well flow rate was maintained at 2,350 gpm (300 gpm lower than the previous year) with the southern extraction well operating in a cyclic pumping mode.

December 2003 EPA issued the Second Amended UAO.January 26, 2004 The Companies submitted a proposal: Staged Restart of Extraction Wells EW-M and

EW-S in February 2004 After SRP Grand Canal Shutdown.

February 6, 2004The Companies submitted Responses to February 2nd EPA Comments on the Staged Restart of Extraction Wells EW-M and EW-S Proposal Dated January 26, 2004.

March 1, 2004The Companies submitted a Proposal to Install One Additional Groundwater Monitor Well Screened in the Basin Fill Deposits South of EW-06 in response to EPA's letter dated February 19, 2004.

March 2004 A new monitor well (NW09-D) was added to better define the lateral and vertical extent of contamination to the south around 20th Street.

March 23, 2004The Companies submitted an Evaluation of Hydraulic Capture After Staged Restart of Extraction Wells EW-M and EW-S on February 11, 2004 after SRP Grand Canal Shutdown.

April 15, 2004 The Companies submitted the 2003 Effectiveness Report.

May 18, 2004The Companies submitted a Notification Letter of a Newly Installed Groundwater Monitor Well NW09-D Preliminary Analytical Results. TCE was found at a concentration of 10 ppb. This well location is slightly outside of the southern extent of capture.

May 28, 2004 The Companies submitted Capture Zone Calculations for OU2. The following analyses were conducted: (1) a flow net was manually drawn; (2) a simple capture zone analysis; (3) an evaluation of groundwater chemistry concentration trends.

July 1, 2004 The Companies submitted a revised Operation and Maintenance Manual.July 14, 2004 The Quarterly Groundwater Monitoring Report for the period March through May

2004 was submitted.July 19, 2004 The Companies submitted a report documenting the abandonment of ADEQ monitor

well EW-12 and the modification of ADEQ monitor well EW-7.

October 14, 2004

The Companies submitted a Work Plan to Install Four Additional Groundwater Monitor Wells. The Work Plan describes the rationale, procedures, and schedule for the groundwater monitor well installations planned to further characterize the extent of chlorinated solvents at the boundaries of the groundwater plume around 20th Street.

October 15, 2004 The Quarterly Groundwater Monitoring Report for the period June through August 2004 was submitted.

November 10, 2004 The Companies submitted the revised Work Plan to Install Four Additional Groundwater Monitor Wells, Operable Unit 2 Area.

January 15, 2005 The Quarterly Monitoring Report for the period September through November 2004 was submitted.

April 14, 2005The Companies submitted the December 2004 through February 2005 Groundwater Monitoring Report, and the Effectiveness Report - 2004 20th Street Groundwater Treatment Facility 52nd Street Superfund Site.

June 14, 2005The Companies submitted the Addendum to the Construction Completion Report, Results of Additional Groundwater Monitor Well (NW09-D2, NW10-D, NW11-D, and NW-12D) Installations.

July 11, 2005 The Companies submitted the March - May 2005 Groundwater Monitoring Report.

Page 4 of 5

Table 1 - Chronology of Events at the OU2 AreaMotorola 52nd Street Superfund Site

Phoenix, ArizonaDate Event

July 27, 2005 Freescale letter submitted requesting EPA concurrence on the sale of portion of the land at 12 N. 20th for the City of Phoenix Light Rail Project.

August 29, 2005 EPA concurrence on sale of 255 square feet of land.September 22, 2005 The Companies submitted the Technical Memorandum including Work Plan to Install

Additional Groundwater Monitor Wells/Piezometers at Four Locations.October 7, 2005 The Companies submitted Responses to EPA September 6, 2005 Comments.October 14, 2005 The Companies submitted the June through August 2005 Groundwater Monitoring

Report.April 14, 2006 The Companies submitted the 2005 Effectiveness Report for OU2.

Notes:

Companies - Refers to Freescale and HoneywellCRA - Conestoga-Rovers Associates

GMR - Groundwater Monitoring ReportOU2 - Operable Unit 2PRP - Potentially Responsible Party

Freescale was used to refer to both Motorola and FreescaleHoneywell was used to refer to both AlliedSignal and Honeywell

TCE - Trichloroethene

ATSDR - Agency for Toxic Substances and Disease Registry

WQARF - Water Quality Assurance Revolving Fund

On the 15th of each month Conestoga-Rovers submitted Monthly Progress Reports.

EPA - U.S. Environmental Protection Agency

ADEQ - Arizona Department of Environmental QualityADHS - Arizona Department of Health Services

Page 5 of 5

Table 2 - Summary of Monthly Progress Reports for the OU2 Treatment SystemMotorola 52nd Street Superfund Site

Phoenix, Arizona

123456789

1011121314151617181920212223242526272829303132333435363738394041424344

A B C D E F G H I J K L M N O P Q R S T USummary of Monthly Progress Reports- Motorola OU2 (From January 2002)

Report Period Dec-01 Jan-02 Feb-02 Mar-02 Apr-02 May-02 Jun-02 Jul-02 Aug-02 Sep-02 Oct-02 Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 May-03 Jun-03 Jul-03

System Operations EW-N and EW-S EW-N and EW-SSignificant Issues None SRP Down None None None None None Flow reduced None EW-S reduced None Flow Reduced None SRP Down SRP Maint. SRP Flooded None EW-S low levels EW-S Reduced None

Percent Operational 97 100 87 99.3 99.3 99.8 100 94 99.9 96.4 99.5 99.6 99.6 100* 100* 87.3* 98.2 99.9 99.9 99.4Carbon Changeout None None None None None Yes Yes None None Yes Yes None None None None None None None None None

Average Well Extraction Rate, gpmEW-NEW-M

EW-S, Cyclic Operation (10/03 to 2/04) Total System Extraction Rate, gpm NR NR NR NR NR NR 3,400 3,250 3,250 3,200 3,200 2,650 2,650 2,650 2,650 2,650 2,650 2,650 2,600 2,600Volume Water Extracted (MG)

Total Volume Extracted 156.8 13.9 126.9 159.8 147.7 150.7 144.5 132.8 134.5 132.8 133.6 114.9 116.4 28.3 50.9 102.3 111.4 117.1 110.8 114.7Cumulative (from 12/01) 156.8 170.7 297.6 457.4 605.1 755.8 900.3 1,033.1 1,167.6 1,300.4 1,434.0 1,548.9 1,665.3 1,693.6 1,744.5 1,846.8 1,958.2 2,075.3 2,186.1 2,300.8

Volume Water Discharged (MG)Report Period 153.8 13.6 124.5 157.3 144.2 148 141.7 131.6 133.2 130.4 131.1 113.3 114.5 27.9 50.5 101.7 109.9 115.8 109.8 113.3

Cumulative (from 12/01) 153.8 167.4 291.9 449.2 593.4 741.4 883.1 1,014.7 1,147.9 1,278.3 1,409.4 1,522.7 1,637.2 1,665.1 1,715.6 1,817.3 1,927.2 2,043.0 2,152.8 2,266.1

VOCs Influent, ug/L(based quarterly sample event) EW-N 85.8 78.3 57.1 41.3 33.7 30.3 21.4

EW-M 457.9 471.8 346.7 281.7 253 276.6 238.1EW-S 298.8 231.8 186.2 148.3 133.9 140.5 97.1

VOCs Combined Influent, ug/L 293.8 NR 292.8 261.2 215 205.7 180.7 215.6 217 183.2 205.3 176 181.6 180.1 201.7 194.9 180 180.5 151.9 167.3VOCs Discharged, ug/L 0 NR 0 15.3 32.2 31.8 4.2 23.8 33.6 53.4 24.8 10.4 15.3 31.9 23.4 22.1 0 0 3.2 13.4Estimated Percent VOC Removal 100 NC 100 94 85 85 82 89 85 71 88 94 92 82 88 89 100 100 98 92Reported Total VOCs Removed, lbs. 384 NR 344 328 225 219 213 213 206 144 201 159 162 35 76 147 167 176 138 147

Cumulative (from 12/01) 384 384 728 1056 1281 1500 1713 1926 2132 2276 2477 2636 2798 2833 2909 3056 3223 3399 3537 3684

Facility Discharge Critera Exceedances None NS None None None None None None None None None None None None None None None None None NoneSRP Discharge Criteria Exceedances None None None None None None None

LegendNC= not calculatedNS= not sampledNR= not reported* = When operational(1) = Breakthrough on 3 of 4 primary GAC units(2) = Reached 82% of TCE discharge standard(3) = No carbon changeout, but spent carbon was removed(4) = Estimated, inadequate surrogate compound recovery

Page 1 of 3

Table 2 - Summary of Monthly Progress Reports for the OU2 Treatment SystemMotorola 52nd Street Superfund Site

Phoenix, Arizona

123456789

1011121314151617181920212223242526272829303132333435363738394041424344

ASummary of Monthly Progress Reports- Motorola

Report Period

System OperationsSignificant Issues

Percent OperationalCarbon Changeout

Average Well Extraction Rate, gpmEW-NEW-M

EW-S, Cyclic Operation (10/03 to 2/04) Total System Extraction Rate, gpmVolume Water Extracted (MG)

Total Volume ExtractedCumulative (from 12/01)

Volume Water Discharged (MG)Report Period

Cumulative (from 12/01)

VOCs Influent, ug/L(based quarterly sample event) EW-N

EW-MEW-S

VOCs Combined Influent, ug/LVOCs Discharged, ug/LEstimated Percent VOC Removal Reported Total VOCs Removed, lbs.

Cumulative (from 12/01)

Facility Discharge Critera ExceedancesSRP Discharge Criteria Exceedances

LegendNC= not calculatedNS= not sampledNR= not reported* = When operational(1) = Breakthrough on 3 of 4 primary GAC units(2) = Reached 82% of TCE discharge standard(3) = No carbon changeout, but spent carbon was rem(4) = Estimated, inadequate surrogate compound rec

V W X Y Z AA AB AC AD AE AF AG AH AI AJ AK AL AM AN AO

Aug-03 Sep-03 Oct-03 Nov-03 Dec-03 Jan-04 Feb-04 Mar-04 Apr-04 May-04 Jun-04 Jul-04 Aug-04 Sep-04 Oct-04 Nov-04 Dec-04 Jan-05 Feb-05 Mar-05

EW-N SRP partially down Continuing EW-M EW-M EW-M EW-M EW-S Pump EW-M FCV & EW-S Motor SRP Flooded & EW-M Repair &None Reduced EW-S Cyclical None None SRP Down and Staged Startup Staged Startup Reduced None Rehab Reduced None Reduced Motor Replaced Repaired; SRP Flooded SRP Flooded Annual Shutdown SRP Shutdown None98.9 99.9 99.9 97.8 99.9 100 99.5 99.9 97.9 99.9 95.3 98.8 100 99.4 94.6 95 86* 0 100* 99.9

None Yes Yes None None None Yes Yes Yes Yes Yes None None Yes Yes None None None None None

650 650 650 0 0 0 0 850 0 0 600* 600 600 600* 0 800/600 6001,450 1,450 1,450 1,650 1,650 1,600 1,600 0 1,400 1,400 1,300 1,300 1300* 1300* 0 1350* 1350

209 209 209 200 200 200 200 200 200 200 200 200* 200* 200* 0 200 2002,600 2,400 2,350 2,309 2,309 2309 1,850 1,850 1,800 1,800 1050 1600 1600 2100* 2100* 2100* 2100* 0 2150* 2150

112 107 98.9 94.5 97 26.4 44.3 73.3 69.7 74.9 49.3 70 68.7 71.8 82.3 75.3 80.2 0 39.0 95.92,412.8 2,519.8 2,618.7 2,713.2 2,810.2 2,836.6 2,880.9 2,954.2 3,023.9 3,098.8 3,148.1 3,218.1 3,286.8 3,358.6 3,440.9 3,516.2 3,596.4 3,596.4 3,635.4 3,731.3

-759.8110.9 105 96.9 93.3 93.3 25.8 43.3 71.8 66.1 73.4 47.7 68.2 67.1 70.3 80.7 74.6 78.9 0 38.8 95.3

2,377.0 2,482.0 2,578.9 2,672.2 2,765.5 2,791.3 2,834.6 2,906.4 2,972.5 3,045.9 3,093.6 3,161.8 3,228.9 3,299.2 3,379.9 3,454.5 3,533.4 3,533.4 3,572.2 3,667.5-742.1

21.5 17 10.7 15 18.7 11.2195.4 192.4 186.2 213.8 220.4104.6 99.4 99.3 120.7 117.4 140.2

154.2 142 151 150.2 161.5 137.3 244.4 218 207.1 182.5 29.2 197.1 190.1 174.4 123 151.5 136.5 NS 141.1 148.236.7 41.5 21.7 12.6 39.3 61.4 27.7 5.2 0 5.2 0 0 2.9 5.6 0 0 1.0 NS 7.8 10.7

76 71 86 92 76 55 89 98 100 97 100 100 98 97 100 100 99 0 94 93110 90 107 108 100 17 80 116 120 111 12 115 107 101 84 95 91 NC 43 110

3794 3884 3991 4099 4199 4216 4296 4412 4532 4643 4655 4770 4877 4978 5062 5157 5248 5248 5291 5401-1032

None None None None None None None None None None None None None None None None None None None NoneNone None None None None None None

Page 2 of 3

Table 2 - Summary of Monthly Progress Reports for the OU2 Treatment SystemMotorola 52nd Street Superfund Site

Phoenix, Arizona

123456789

1011121314151617181920212223242526272829303132333435363738394041424344

ASummary of Monthly Progress Reports- Motorola

Report Period

System OperationsSignificant Issues

Percent OperationalCarbon Changeout

Average Well Extraction Rate, gpmEW-NEW-M

EW-S, Cyclic Operation (10/03 to 2/04) Total System Extraction Rate, gpmVolume Water Extracted (MG)

Total Volume ExtractedCumulative (from 12/01)

Volume Water Discharged (MG)Report Period

Cumulative (from 12/01)

VOCs Influent, ug/L(based quarterly sample event) EW-N

EW-MEW-S

VOCs Combined Influent, ug/LVOCs Discharged, ug/LEstimated Percent VOC Removal Reported Total VOCs Removed, lbs.

Cumulative (from 12/01)

Facility Discharge Critera ExceedancesSRP Discharge Criteria Exceedances

LegendNC= not calculatedNS= not sampledNR= not reported* = When operational(1) = Breakthrough on 3 of 4 primary GAC units(2) = Reached 82% of TCE discharge standard(3) = No carbon changeout, but spent carbon was rem(4) = Estimated, inadequate surrogate compound rec

AP AQ AR AS AT AU AV AW AX AY AZ BA BB BC BD

Apr-05 May-05 Jun-05 Jul-05 Aug-05 Sep-05 Oct-05 Nov-05 Dec-05 Jan-06 Feb-06 Mar-06 Apr-06 May-06 Jun-06Shutdown -elevated TCE SRP Annual

None None None None None None None None discharge Shutdown None None None None None99.9 99.9 99.8 99.9 94.0 100.0 99.6 98.2 76.5 13.9 80.9 98.8 99.7 99.8 99.4

None None None None Yes Yes None None(1) Yes Yes None(3) None(3) Yes None None

600 600 600 600 600 600 600 600 600* 600* 600* 600 600 600 6001350 1350 1350 1350 1350 1350 1350 1350 1350* 1350* 1350* 1350 1350 1350 1350

200 200 200 200 200 200 200 200 200* 200* 200* 200 200 200 2002150 2150 2150 2150 2150 2150 2150 2150 2150* 2150* 2150* 2150 2150 2150 2150

92.4 95.2 90.6 94.3 88.6 92.0 95.0 90.2 69.9 16.1 68.8 93.5 90.9 92.9 89.53,823.7 3,918.9 4,009.5 4,103.8 4,192.4 4,284.4 4,379.4 4,469.6 4,539.5 4,555.6 4,624.4 4,717.9 4,808.8 4,901.7 4,991.2

91.7 93.7 89.1 93.3 87.4 90.2 93.1 89.0 68.5 15.7 67.9 93.0 90.1 92.9 89.63,759.2 3,852.9 3,942.0 4,035.3 4,122.7 4,212.9 4,306.0 4,395.0 4,463.5 4,479.2 4,547.1 4,640.1 4,730.2 4,823.1 4,912.7

13.2 16.7 21.2 15.8(4)

251.8 234.3 269.4 269.2(4)

100.2 94.9 87 84.7(4)

161.5 188.1 172.5 224 105.2 161.4 184.3 177.1 189.1 177.6 185.6 177.2 217.1 169.7(4) 188.8(4)

23.3 17.7 0 3 15 0 3 12.6 0 0 0 1.4 7.8 0(4) 0(4)

86 91 100 99 86 100 98 93 100 100 100 99 96 100 100107 135 130 174 67 124 144 124 110 24 106 137 157 132 141

5508 5643 5773 5947 6014 6138 6282 6406 6516 6540 6646 6783 6940 7072 7213

None None None None None None None None(2) None None None None None None NoneNone None None None None

Page 3 of 3

Table 3 - Annual O&M Costs for the OU2 Treatment SystemMotorola 52nd Street Superfund Site

Phoenix, Arizona

Year Total O&M Costs2001 $415,7021

2002 $1,027,5082003 $776,4312004 $1,009,5402005 $828,500

Notes: 1. The total for 2001 reflects the timing of the start-up and commissioning of the OU2 system.

Table 4 - Actions Taken Since the Last Five-Year Review for OU2Motorola 52nd Street Superfund Site

Phoenix, Arizona

Issues from Previous Review Recommendations/Follow-up Actions Party Responsible

Milestone Date Action Taken and Outcome Date of Action

Evaluation of lower flow rates in extraction wells particularly EW-S not completed and revised model inputs have not been provided.

PRPs will submit remaining information and EW-S analysis and model inputs. EPA and ADEQ will need to conduct a thorough review of data.

Honeywell & Motorola 10/15/2001

The Companies have evaluated EW-S on a number of occasions including in Results of Hydrogeologic and Construction Services for Installation of Extraction and Monitor Wells, 52nd Street Superfund Site, Operable Unit 2, Phoenix, Arizona report dated August 29, 2002., the 2002 Effectiveness Report , the Capture Zone Calculations - Operable Unit 2 letter report (2004), and the 2005 Effectiveness Report .

8/29/2002

Hydraulic monitoring well network possibly not adequate. PRPs will update the Draft O&M Manual. EPA and ADEQ will need to conduct a thorough review of modified monitoring plans.

Honeywell & Motorola 10/24/2001

A Final O&M Manual was submitted to EPA and ADEQ on January 25, 2002. The Final O&M Manual was revised on July 14, 2004.

1/25/2002 and 7/14/2004

Institutional controls regarding access to groundwater are not identified in the ROD as part of the remedy.

EPA and ADEQ will evaluate institutional controls regarding access to contaminated groundwater for the final remedy. EPA/ADEQ NA A final remedy for OU2 has not been selected

yet. 3/31/2008

Well inventory information is outdated. ADHS will complete a Draft Public Health Assessment on groundwater well use and make recommendations for further assessment. ADHS/ATSDR 10/26/2001

ADHS prepared a Status Verification of Private Drinking Water Wells, Motorola 52nd Street Superfund Site report.

4/17/2002

ARARs are not very specific. EPA and ADEQ will evaluate more specific ARARs and also consider AZ Surface Water Limits during final remedy evaluation. EPA/ADEQ NA A final remedy for OU2 has not been selected

yet. 3/31/2008

Boron is detected at the Arizona Surface Water Limit for agricultural irrigation, and is not in the Companies monitoring program.

PRPs will add boron to the treatment plant monitoring program and the data will be reviewed to confirm protectiveness is not impacted.

Honeywell & Motorola 10/15/2001

Groundwater samples were collected and analyzed for boron in 2001 and 2002. Boron was detected at levels slightly above the surface water limit for agricultural irrigation.

2001/2002

New chemicals of potential concern have been detected in the aquifer, as well as some chemicals may not longer be of concern.

The list of COPC should be modified to reflect current groundwater conditions prior to next risk assessment. Monitoring program should be revised accordingly (mercury should be evaluated).

Honeywell & Motorola 10/15/2001

Groundwater samples were collected and analyzed for metals, inorganics, VOCs, and cyanide in 2001 and 2002. Boron was the only compound other than the known COCs to be detected above a standard.

2001/2002

Model used for indoor air risk evaluation is outdated and there are new inhalation toxicity values.

Previous risk calculations for "current risk scenario in the baseline risk assessment (1992)" should be updated and air risk modeled using new model.

EPA or ADHS/ATSDR 4/1/2002

EPA is currently developing guidance for evaluating indoor air risk. Once the guidance is finalized it should be used to evaluate risks.

on going

Page 1 of 1

Table 5 - Summary of Current Chemical-Specific StandardsMotorola 52nd Street Superfund Site

Phoenix, Arizona

Authority Medium Requirements Requirement SynopsisRemedy Compliance with Current

StandardsFederal safe Drinking Water Maximum Contaminant Levels (MCLs) for organic and inorganic chemicals (40 CFR 141 Subparts B and G)

MCLs have been promulgated for a number of common organic and inorganic contaminants. These levels regulate the concentrations of contaminants in public drinking water supplies, and are considered relevant and appropriate for groundwater aquifers potentially used for drinking water.

Current groundwater conditions within the Site have shown that many of the contaminants of concern are above their specific MCLs in OU2 wells. This may be an ARAR for the final remedy.

EPA Region IX. Preliminary Remediation goals (PRGs).

EPA Region IX guidelines establishing concentrations of compounds in tap water considered to be protective of human health.

VOCs such as 1,4-Dioxane have been detected in groundwater. This may be an ARAR for the final remedy.

Wastewater

Federal safe Drinking Water Maximum Contaminant Levels (MCLs) for organic and inorganic chemicals (40 CFR 141 Subparts B and G)

ARARs established in the ROD and ESD requires that treated groundwater effluent meet drinking water standards with exceedances of MCLs.

Yes

AirEPA Region IX. Preliminary Remediation goals (PRGs).

EPA Region IX guidelines establishing concentrations of compounds in air considered to be protective of human health.

This may be an ARAR for the final remedy.

Arizona Aquifer Water Quality Standards (AWQS), (AAC R18-11-109, AAC R18-11-406)

Statewide aquifer protection standards for organic and inorganic compounds, established for drinking water protective usage. Many of the compound concentrations are comparable to the Federal MCLs. If the AWQSs are more stringent than the MCLs, than the AWQSs should be used.

Current groundwater conditions within the Site have shown that many of the contaminants of concern are above their specific AWQSs in OU2 wells. This may be an ARAR for the final remedy.

ADEQ's (Office of Environmental Health) Human Health-Based Guidance Levels (HBGLs) for the Ingestion of Contaminants in Drinking Water, December 1997

This guidance document lists a variety of compounds that provides different concentration/limits based upon: calculated risk-based ingestion concentrations; MCLs; proposed MCLs; and state laboratory levels of quantitation values.

Current groundwater conditions within the Site have shown that many of the contaminants of concern are above their specific HBGLs in OU2 wells. This may be an ARAR for the final remedy.

Arizona Ambient Air Quality Guidelines ADEQ issues permits to industries and facilities that emit regulated pollutants to ensure that these emissions do not harm public health or cause significant deterioration in areas that presently have clean air.

This may be an ARAR for the final remedy.

Maricopa County VOC Limitation This standard limits VOC emissions from any source within Maricopa County to less than 3 pounds per day.

This may be an ARAR for the final remedy.

Air

Groundwater

Groundwater

Federal Regulatory Requirements

State and Local Regulatory

Requirements

Page 1 of 1

Table 6 - Summary of Location and Action-Specific StandardsMotorola 52nd Street Superfund Site

Phoenix, Arizona

Authority Requirements Requirement Synopsis Remedy Compliance with ARARs

Endangered Species 16 U.S.C. §1531 et seq.

If endangered species are found within or adjacent to the site, remedial actions shall comply with the substantive portions of the requirements for endangered species in accordance with the Endangered Species Act.

Yes

Fish and Wildlife 16 U.S.C. §661 et seq., 40 CFR §6.302

Remedial actions shall protect the fish and wildlife of the area in accordance with 16 U.S.C. §661 et seq.

Yes

National Archeological and Historical Preservation Act, 16 U.S.C. §469, 36 CFR Part 65, A.R.S. §41-841-847 and A.R.S. §41-865

The substantive portions of the laws governing archeological discovery and preservation shall be followed if artifacts or human remains are discovered.

Yes

Federal Hazardous Materials Transportation Law, 49 U.S.C. §§ 5401, et seq. and associated rules, 40 CFR Parts 107, 171.1 - 172.558

This law regulates the transportation of hazardous substances.

Yes

Section 402 of the Clean Water Act, 33 U.S.C. §1342

Requires a National Pollution Discharge Elimination System (NPDES) permit for discharge of pollutants to waters of the United States. Discharge to the Grand Canal is within the Site boundary, therefore, the substantive requirements of §402 of the Clean Water Act is an ARAR.

Yes

State and Local Regulatory Requirements

New Well Construction & Groundwater Use Requirements A.R.S., Title 45; 45 A.R.S. §454.01; and A.R.S. §45-594, -595, and -596

For activities conducted onsite, the substantive portions of the Arizona Groundwater Management Act Section 45-454.01 (GMA) are applicable. Remedial actions undertaken pursuant to CERCLA must meet the following requirements: a new well is subject to sections 45-594 (Well construction standards); 45-595 (Well construction requirements; licensing of well drillers and pump installation contractors); withdrawn groundwater must be reinjected into the aquifer of be put to reasonable and beneficial use, and a person who uses groundwater withdrawn in an active management area may be subject to the withdrawal fee and shall use the groundwater only pursuant to Articles 5-12 of Title 45 , Chapter 2; and 3.

Yes

Location-Specific ARARs

Action-Specific ARARs

Federal Regulatory Requirements

Federal Regulatory Requirements

Page 1 of 2

Table 6 - Summary of Location and Action-Specific StandardsMotorola 52nd Street Superfund Site

Phoenix, Arizona

Authority Requirements Requirement Synopsis Remedy Compliance with ARARs

State and Local Regulatory Requirements

Arizona Air Pollution Control Regulations A.R.S. 49-401 et seq.; Maricopa County Air Pollution Control Regulations Rules 200, 210, 220, and 320

As a part of the delegated program, the Maricopa County Air Pollution Control Regulations adopted by the Board of Supervisors, October 1, 1990, Maricopa County Air Quality Standards (Rules 200, 210, 220, and 320) are part of the State Implementation Plan as dictated by the Clean Air Act and/or 40 CFR 264, Subparts AA and BB. The substantive portions of the regulations are applicable for remediation of groundwater at the site.

Yes

"Contained in" principle Arizona Hazardous Waste Management Act (AAC R18-8-261)

The "contained in" principle provides that any non-waste material (e.g., groundwater) that contains a listed hazardous waste must be managed as if it were a hazardous waste. Groundwater extracted as part of this interim remedy will contain a listed hazardous waste, therefore these regulations are applicable to the management of that groundwater.

Yes

Arizona Hazardous Waste Management Act, AAC R18-8-262

The regeneration or disposal of spent carbon or other media after use to control emissions of VOCs must be managed in conformance with the generator requirements of the state Hazardous Waste Management Act, including disposal at a permitted hazardous waste facility.

Yes

Arizona Hazardous Waste Management Act Land Disposal Restrictions, AAC R18-8-268

Groundwater treatment residuals or other media contaminated with volatile organic compounds are banned from land disposal. Treatment standards must be met before wastes can be land disposed.

Yes

ROD ESD Requires that the treated groundwater treated groundwater effluent meet drinking water standards with no exceedances of MCLs.

Yes

Page 2 of 2

Table 7 - Confirmation of Chemical-Specific Toxicity Values for OU2 AreaMotorola 52nd Street Superfund Site

Phoenix, Arizona

Chemical of Concern Toxicity Value NameSource

(oral/inhal.) Impact on Risk Assessment

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation) 1.9 / 0.3 EPA, 1997

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) 1.5 / 0.031 EPA, 2004

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation) 0.6 / 0.18 EPA, 1999

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) 0.6 / 0.18 EPA, 1999

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation) 0.0061 / 0.081 EPA, 1999

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) 0.031 / 0.019 EPA, 2004

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation) 0.011 / 0.006 EPA, 1999

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) 0.013 / 0.007 EPA, 2004

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation) 0.029 / 0.027 EPA, 1999

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) 0.055 / 0.027 EPA, 2004

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation) 0.052 / 0.002 EPA, 1999

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) 0.54 / 0.021 EPA, 2004

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation)

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) 0.011 / 0.011 EPA, 2004

Cancer Slope Factor [SF] (mg/kg-day)-1

Previous (oral/inhalation)

Cancer Slope Factor [SF] (mg/kg-day)-1

Current (oral/inhalation) NL / 420 EPA, 2004

Impact on the risk assessment de minimis.

Impact on the risk assessment needs to be evaluated.

Impact on the risk assessment de minimis.

Not Evaluated Previously

Impact on the risk assessment needs to be evaluated.

Impact on the risk assessment needs to be evaluated.

Impact on the risk assessment needs to be evaluated.

Not Evaluated Previously

Chloroform

Trichloroethene

Benzene

Total Chromium

Tetrachlorethene

1,4-Dioxane

Toxicity Value

Vinyl Chloride

1,1-Dichloroethene

COCs with Carcinogenic Endpoint

Impact on the risk assessment de minimis.

Impact on the risk assessment needs to be evaluated.

Page 1 of 2

Table 7 - Confirmation of Chemical-Specific Toxicity Values for OU2 AreaMotorola 52nd Street Superfund Site

Phoenix, Arizona

Chemical of Concern Toxicity Value NameSource

(oral/inhal.) Impact on Risk Assessment

Reference Doses (mg/kg-day)

Previous (oral/inhalation) 0.1 / 0.14 EPA, 1997

Reference Doses (mg/kg-day)

Current (oral/inhalation) 0.0057 / 0.0057 EPA, 2004

Reference Doses (mg/kg-day)

Previous (oral/inhalation) 0.09 / 0.3 EPA, 1991

Reference Doses (mg/kg-day)

Current (oral/inhalation) 0.035 / 0.29 EPA, 1999

Reference Doses (mg/kg-day)

Previous (oral/inhalation) 0.02 / NL EPA, 1991

Reference Doses (mg/kg-day)

Current (oral/inhalation) 0.02 / 0.02 EPA, 1999

Reference Doses (mg/kg-day)

Previous (oral/inhalation) 0.02 / 0.005 EPA, 1991

Reference Doses (mg/kg-day)

Current (oral/inhalation) 0.02 / 0.017 EPA, 1999

Notes:NL - Not Listed

Impact on the risk assessment de minimis.

Impact on the risk assessment de minimis.

Impact on the risk assessment de minimis.

Toxicity Value

Impact on the risk assessment de minimis.

COCs with Noncarcinogenic Effects

1,1,1-Trichlorethane

trans-1,2-Dichloroethene

Chlorobenzene

1,1-Dichloroethane

Page 2 of 2

Table 8 - Identified Issues and Noted Concerns for OU2Motorola 52nd Street Superfund Site

Phoenix, Arizona

Current Future

1

Little to no groundwater elevation and quality data are available in any of the subunits along the north side of the OU2 plume. As a result, the impact of the OU2 treatment system can not be adequately evaluated in that area. Additional monitoring wells are needed along the north side of the OU2 plume in each of the subunits to evaluate the OU2 capture effectiveness.

Yes Unknown

2

Groundwater elevation and quality data are lacking in all three subunits along the south side of the OU2 plume. As a result, the impact of the OU2 treatment system is difficult to assess in this area. Additional monitoring wells are needed along the south side of the OU2 plume in each of the subunits to evaluate the OU2 capture effectiveness.

Yes Unknown

3

Additional groundwater elevation and quality data are needed downgradient of the OU2 treatment system to evaluate capture in the D subunit. Additional monitoring wells are needed in the D subunit downgradient of the OU2 treatment system to evaluate capture in subunit D.

Yes Unknown

4

Although capture appeared more effective in 2005, it appears to be related to a northwest rotation of groundwater gradients due to recharge from the Salt River flow event. However, based on a conservative interpretation of the data, using converging lines of evidence, it appears the TCZ along the south side of the plume is not fully captured.

Yes Unknown

5

EW-S groundwater extraction rates have declined. The well was designed to operate at 1,700 gpm. The initial extraction rate for the well was approximately 800 gpm and has declined to the current extraction rate of approximately 200 gpm. If the rate declines further in the future, capture to the south may also be reduced.

Unknown Unknown

6

Future containment of the D subunit is problematic because: the D subunit is primarily contaminated in the south portion of OU2, EW-S does not penetrate the D subunit and therefore does not directly extract from the D subunit, and capture is currently questionable and may decrease if EW-S extraction rates continue to decline.

Unknown Unknown

7The Agencies are concerned that the stagnation zone on the upgradient and downgradient side of the Honeywell bedrock ridge is not being addressed by the OU2 system.

Unknown Unknown

8Long-term multi-well aquifer tests in subunits B and D are needed to gain a better understanding of the OU2 conceptual site model and to facilitate future OU2 analyses.

Unknown Unknown

9

The OU2 system is an interim remedy and therefore a final remedy for OU2 must be developed. The final remedy will necessarily address the issues identified in this five-year review and must consider and integrate the Honeywell light nonaqueous phase liquid (LNAPL) remedy.

Unknown Unknown

10Changes to the toxicity levels for certain contaminants have occurred since the last five-year review. Unknown Unknown

11

New methodology is being developed for indoor air risk evaluation. Once the methodology is finalized or EPA and ADEQ can agree to the process for evaluating the pathway, an indoor air risk evaluation should be performed for the OU2 area.

Unknown Unknown

12Boron has been detected in influent and effluent samples from the treatment plant. Unknown Unknown

13 General Issues

The 2005 Effectiveness Report is not consistent with respect to the lithologic and hydrogeologic representation and interpretation of the D subunit. Cross section Figure 2.6 does not include the interpretation of bedrock or the D subunit on the east portion of the cross-section. Figure 3.9 does not depict the area where the D subunit is pinched-out by the OU2 bedrock ridge. Consistent interpretation of the hydrostratigraphic subunits and available data is needed for OU2 analyses (e.g., interpretation of subunit D as both unconfined and semiconfined). Additionally, consistent use of available data is needed for OU2 analyses (e.g., D subunit groundwater elevations along the north side of OU2).

Unknown Unknown

Notes

Protectiveness Affected?

VOC - Volatile Organic Compounds

TCE - TrichloroethenePCE - Tetrachloroethene

Issue Type Issues

ADEQ - Arizona Department of Environmental QualityOU2 - Operable Unit 2EPA - Environmental Protection AgencyMCL - Maximum Contaminant Level

Health Assessment

Issues

#

Groundwater Capture Issues

Groundwater Future Issues

Page 1 of 1

Table 9 - Follow-up Actions and RecommendationsMotorola 52nd Street Superfund Site

Phoenix, Arizona

Reference Number*

Recommendation Follow-up Actions/Recommendations Responsible Party

Oversight Agency

Completion Date

1

A work plan should be prepared and submitted to ADEQ to address the data gaps along the north side of the OU2 plume. The work plan should include the installation of monitor wells in each of the three alluvial subunits.

The Companies EPA, ADEQ 9/28/2007

2

A work plan should be prepared and submitted to ADEQ to address the data gaps along the south side of the OU2 plume. The work plan should include the installation of monitor wells in each of the three alluvial subunits.

The Companies EPA, ADEQ 9/28/2007

3

A work plan should be prepared and submitted to ADEQ to address the data gaps downgradient of the OU2 treatment system. The work plan should include the installation of monitor wells in the D subunit.

The Companies EPA, ADEQ 9/28/2007

4

Future capture evaluations shall include a conservative interpretation of groundwater elevation data, an analysis of water level pairs for appropriately configured monitor wells, capture zone calculations that are conceptually consistent with site data and interpretation, and concentration trend analysis that includes historic data.

The Companies EPA, ADEQ 3/30/2007

5 The Companies should continue to monitor the extraction rates for EW-S. The Companies EPA, ADEQ 9/28/2007

6The Companies should develop a plan to monitor groundwater capture along the southern boundary, particularly in subunit D. The Companies EPA, ADEQ 9/28/2007

7

The Companies should prepare a plan to evaluate the effectiveness of the OU2 treatment system on the stagnation zones upgradient and downgradient of the Honeywell bedrock ridge.

The Companies EPA, ADEQ 9/28/2007

8

The Companies should develop a plan to conduct long-term multi-well aquifertests in subunits B and D. The data obtained from these tests will be useful for designing a final remedy for OU2.

The Companies EPA, ADEQ 9/28/2007

9 The final OU2 remedy will need to incorporate the Honeywell LNAPL remedy. EPA, ADEQ EPA, ADEQ September 2008

10A review of the toxicity values for COCs at the Site should be conducted before the final remedy is selected. EPA, ADEQ EPA, ADEQ On going

11

New methodology is being developed for indoor air risk evaluation. Once the methodology is finalized or EPA and ADEQ can agree to the process for evaluating the pathway, an indoor air risk evaluation should be performed for the OU2 Area.

The Companies EPA, ADEQ

1 year following ADEQ and EPA agreement on

process

12

Effluent samples should be collected and analyzed for boron. If the results are above the surface water limit for agricultural irrigation, SRP should be notified.

The Companies EPA, ADEQ 3/30/2007

13General Issues

The Agencies recommend a technical work group meeting to discuss and address groundwater elevation and quality data, capture issues, and hydrostratigraphic issues.

The Companies, ADEQ EPA, ADEQ 12/1/2006

Notes

ADEQ - Arizona Department of Environmental QualityCOC - Contaminant of ConcernCOP - City of PhoenixEPA - Environmental Protection AgencyMCL - Maximum Contaminant LevelO&M - Operation and MaintenanceOU2 - Operable Unit 2The Companies - Refers to Freescale and HoneywellTCE - TrichloroetheneVOC - Volatile Organic Compounds

* Refer to Table 8 for reference number

Follow-up Actions

Groundwater Capture Issues

Groundwater Future Issues

Health Assessment Issues

Page 1 of 1

FIGURES

MOTOROLA 52ND STREET SUPERFUND SITEPHOENIX, ARIZONA

Figure 4OU2 Flow Schematicand Hydraulic Profile

MOTOROLA 52ND STREET SUPERFUND SITEPHOENIX, ARIZONA

Figure 5

OU2 GAC System

MOTOROLA 52ND STREET SUPERFUND SITEPHOENIX, ARIZONA

Figure 6

OU2 Typical GAC Unit

MOTOROLA 52ND STREET SUPERFUND SITEPHOENIX, ARIZONA

Figure 7OU2 UV Unit -Chemical Storage

MOTOROLA 52ND STREET SUPERFUND SITEPHOENIX, ARIZONA

Figure 8OU2 Extraction WellDiagram

Appendices and Attachments for this Five-Year Review are available by placing a request using the Customized CERCLIS/RODS Report Order Form.

http://www.epa.gov/superfund/sites/phonefax/rods.htm