TOW 001 002075

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

R E G I O N IV343 COURTLAND STREET

ATLANTA. GEORGIA 30363

DECLARATION FOR THE RECORD OF DECISION

Tbwer Chemical Company siteClermont, Florida

STATEMENT OF PURPOSE

This decision document represents the selected remedial action for the TowerChemical Company site which was developed in accordance with the ComprehensiveEnvironmental Response, Compensation and Liability Act (CERCIA), as amendedby the Superfund Amendments and Reauthorization Act (SARA), and to theextent practicable, the National Contingency Plan (NCP).

The State of Florida has concurred with the selected remedy and has agreedto provide funding for 10% of the Remedial Action cost which is estimatedto be $6.8 million.

STATEMENT OF BASIS

This decision is based on the administrative record which is on file in theEPA Region IV offices, 345 Courtland Street, Atlanta, GA or is available atthe Cooper Manorial Library, 620 West Montrose Street, Clermont, Florida.The attached index identifies the documents which comprise the administrativerecord upon which the selection of a remedial action is based.

DESCRIPTION OF THE SELECTED REMEDY

Qroundwater recovery operations will be conducted to remove all groundwaterwhich contains contamination in excess of the criteria presented in SectionVIII of the Summary of Remedial Alternative Selection. Recovered groundwaterwill be treated in an on-site treatment facility. Treated groundwater willbe stored on-site until analytical results confirm that the effluent meetsthe established clean-up criteria. Disposal will be via surface waterdischarge. Groundwater recovery operations will be considered as~part ofthe Remedial Action for 10 years from inception or until the groundwaterclean-up goals are reached; whichever occurs first. If the groundwaterrecovery system is still operating after 10 years, the efficiency of thegroundwater recovery system will be re-evaluated.

Individual treatment units will be provided for the two active wells withinthe immediate site vicinity: one owned by Mr. and Mrs. Charles Hubbard andone owned by Classic Manufacturing Inc. which provides potable water tothe employees of Vita-Green, Inc. EPA will maintain the units until thegroundwater recovery is complete.

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TOW 001 00207G

Surface soil removal will be conducted in the overflow area of the formerwaste water pond, the burn/burial area, around the storage tanks, andall soils which have contaminant concentrations in excess of the clean-upcriteria established in Section VIII of the Summary of Remedial ActionSelection. This will be approximately 4,000 cubic yards.

Excavated soils will be treated on-site by thermal destruction of the con-taminants. Thermally treated soils will be analyzed after the test burn todetermine the proper action for residual management. Exploration of thebum/burial area to determine the source of a magnetic anomaly will be con-ducted in conjunction with the soil removal program, if relic drums areidentified, the contents will be typed and disposed of by thermal destruction.In addition, two storage tanks and nearby concrete pads from the TowerChemical Co. operations will be decontaminated. Any sludges fron the tankswill be thermally destroyed and wash down fluids will be treated in the on-site treatment facility. The decontaminated tanks will be recycled and theconcrete pads will be backfilled with the treated soils.

Point source run-off diversion will divert run-off from the main buildingroof and the wash down waters for the Vita-Green Company to reduce erosionof the soils. All areas affected by implementation of the selected remedywill be regraded and revegetated to enhance soil stability.

Operation and maintenance activities will be limited to verification of thecompleteness of the Remedial Action since all site contaminants will bedestroyed.

DECLARATION

The selected remedy is protective of human health and the environment,attains Federal and State requirements that are applicable or relevant andappropriate, and is cost-effective. This remedy satisfies the preferencefor treatment that reduces toxicity, mobility, or volume as a principalelement. Finally, it is determined that this remedy utilizes permanentsolutions and alternative treatment technologies to the maximum extentpracticable.

Jack E. Ravan ' 'Regional Administrator

CL4

TOW 001 002077

Tower Chemical Company SiteAdministrative Record Index

Action Memorandum

Community Relations Plan

Decision Memorandum

Environmental Service Division Investigation Report

Feasibility Study -- Draft Final

Feasibility Study Appendices -- Draft Final

Geologic Profile

Hazard Ranking System Score

Hydrogeologic Tests

Indicator Chemicals used in the Remedial Investigation

Intergovernmental Review Letter

Natural Resouces Damage Assessment

Public Health Evaluation

PuDlic Meeting Transcripts 9/16/86

RCRA Land-Ban Policy

Remedial Action Master Plan

Remedial Investigation Volume I Final

Remedial Investigation Volume II Final

Remedial Investigation Site Operation Plan

Remedial Investigation/Feasibility Study Work Plan

Removal Action Report

Responsiveness Summary

Risk Assessment

Soil Technologies Letter Report

As of 6/24/87

TOW 001 002078

SECTION ISITE LOCATION AND DESCRIPTION

The Tower Chemical Company (Tower) NPL Site is located on County Road 455along the eastern edge of Lake County, Florida. The site is 3.8 miles eastof Clermont, Florida and 15 miles west of Orlando, Florida (Figure 1). TheTower site is an abandoned facility which manufactured various pesticidestrcm 1957 to 1981.

The Tower Chemical Company owned and utilized two separate parcels of landduring the time the company was in operation: a main facility and a sprayirrigation field.

The main facility (Figure 2) consisted of a production building, a smallutility building, an office, and two disposal areas: a burn/burial areafor solid wastes and a percolation/evaporation pond for acidic wastewaters.

The spray irrigation field covers approximately seven acres and consists ottour parallel strips of land (Figure 3). A series of spray beds were usedin 1980 tor discharging process wastewaters.

The site is relatively flat across the main facility with only about 5 feetot relief. The spray irrigation field shows about 20 teet ot relief,descending from south to north. Both portions of the site drain intoswampy areas which eventually drain into an unnamed stream north of thesite, which in turn, drains into the Gourd Neck area of Lake Apopka. Thelake and nearby swamps and wetlands provide an important natural habitatfor local wildlife, including nesting bald eagles.

Within a 1.2 mile radius of the site, land use consists of agriculturallands (48%), lakes and wetlands (31%), range land and forest (9%), extraction/transitional lands (7%), residential property (less than 3%), and commercial/industrial land (less than 2%).

Locally there is no central water supply; thus, approximately 16 localhouseholds (60 consuners) rely on private wells which tap the FloridanAquifer for their water supply. Within the site area, no surface waterresources are used for drinking water supplies, but Lake Apopka is used forrecreational purposes.

TOW 001 002079

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tlMINOLICOUNTY

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TOWER CHEMICALCOMPANY 8ITE

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Figure 1A - Site Location Map, Tower Chemical Company Site.

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TOW 001 002083

SECTION IISITE HISTORY

OPERATIONAL HISTORY

Fran 1957 to 1981, the Tower Chemical Company manufactured, formulated, andstored various pesticides. The two main products produced by Tower werechlorobenzilate (a miticide) and a copper-based agricultural fungicide witnthe trade name "Cop-o-cide". In order to produce chlorobenzilate it wasnecessary to eitner buy or manufacture the compound dichlorobenzil. Duringperiods in which dichlorobenzil was ditticult to obtain, the Tower Chemicalcompany manufactured it in-house from dichloro-diphenyl-tricnloroethane(DOT). This operation was used during the last few months of the Company'soperation.

Acidic wastewaters were produced during the manufacturing process.Originally, these wastewaters were discharged into the unlined percolation/evaporation pond located at the main facility. In July 1980, the sprayirrigation field was operational and was being used for discharge of theacidic wastewaters. The spray irrigation field was used because thepercolation/evaporation pond was full, and in fact did overflow its banksduring July 1980.

The burn/burial area had historically been used as a burning ground fordisposal of the company's solid chemical wastes and for burial of solidwastes. The buried wastes were both drummed and undrummed wastes.

As a result of the percolation/evaporation pond overflow, the FloridaDepartment of Environmental Regulation (FDER) and the U.S. EnvironmentalProtection Agency (EPA), initiated site investigations in early 1981. InDecember 1980 all production operations were stopped at the Tower ChemicalCompany and the facility was decommissioned during 1981.

In 1981, prior to the deccnmissioning, the warrenty deed tor the propertyowned by the Tower Chemical Company Plant was transferred to James E.Gallagher, as trustee and tne spray irrigation field was sold to O.T.Enterprises.

After closure of the Tower Chemical Company, two new businesses were openedon the main facility: Classic Manufacturing Company and Vita-Green Inc.From 1981 to 1986, Classic Manufacturing used about 1 acre of the mainfacility for the manufacture of plastic worm tisning lures. During thesummer of 1986, Classic Manufacturing moved to a new location off-sitealthough Classic still holds the property deed. After leasing an otherportion of the property, Vita-Green, Inc. moved onto the site in September1981. This company blends potting soils and packages it tor home gardenuse. Vita-Green is still actively operating on the western portion of themain facility.

TOW 001 002084

The area used for the eastern portion of the spray irrigation field wasbought jointly in the early lyau's by Ms. Mabel Watson and Mr. WilliamWatson, Jr. Both owners now live on the property and use the land forcattle and goat grazing as well as sugar cane cultivation. The westernportion was purchased by Mr. Ben Harrison who has built his home on theproperty and used most of the land to establish a wholesale nursery.

None of the activities subsequent to the Tower Chemical Company operationshave significantly impacted the site.

PERMIT AND REGULATORY HISTORY

The permit and regulatory history began in July 1979, when the Tower ChemicalCompany applied for a National Pollutant Disharge Elimination System(NPDES) permit, followed in November 197y, by an application to constructan industrial wastewater treatment and disposal system. These applicationsreferred to occasional discharge of wastewater into the unnamed stream attimes of flooding and to the construction of the spray irrigation field.The EPA did not.issue the NPDES permit, but the FDER did grant a Permit toConstruct for the spray irrigation system. The conditions of the constructionpermit included an initial period of operation for appropriate testing todetermine compliance with the permit conditions. The permit requiredthe installation of monitoring wells before use of the area as a disposalsite to determine background water quality. Groundwater monitoring everysix months after operational start-up was also a condition of the permit.

As a result of the damages caused by the wastewater pond overflow, on June5, 1980, FDER ordered Tower Chemical Company to cease all discharges fromthe site. The Tower Chemical Company responded to the order and assuredFDER of compliance. In July 1980, the State Circuit Court ruled that theTower Chemical Company could continue to operate only if the company metthe FDER requirements. From this point, Tower Chemical Company and FDERentered into negotiations to define the clean-up process tor the site.Meanwhile, FDEK pursued legal action against the Tower Chemical Company andits president, Mr. Ralph Roane.

In August 1980, EPA conducted a preliminary hazardous waste site investigationof the Tower Chemical Company site. The site received a Hazardous RankingSystem (HRS) score of 44.03 (Appendix A). As a result of the HRS score,the Tower Chemical Company site was proposed for inclusion on the NationalPriorities List of Hazardous Waste Sites (NPL) in October 1981. The sitewas finalized on the NPL in December 1982.

On June 15, 1982, FDER, Tower Chemical Company, and Mr. Ralph Roane agreedto the entry of a Consent Final Judgement in which Tower Chemical Companywas to pay compensatory damages in the amount of $10,000,000 and Mr. Roanewas to pay $40,000.

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TOW 001 002085

In development of a clean-up plan, EPA provided input to FDER regarding theneed to prepare a feasibility study (FS) to develop a range of remedialalternatives. The Tower Chemical Company agreed to prepare an FS. Inter-actions occurred over a period of about one year among EPA, FDER, and TowerChemical Company, but the FS was not developed. In February 1983, FDERconsidered filing for contempt of court because neither the company nor Mr.Roane had paid the court-ordered judgements. Instead of taking furtherlegal action, FDER requested that EPA acguire the management role for theremedial planning process for the Tower site.

In March 1984, EPA tasked NTJS Corporation, under the original REM-FITcontract, to conduct a Remedial Investigation and Feasibility Study (RI/FS)for this site.

A public meeting was held on September 16, 1986, to present the draftRemedial Investigation report and the draft Feasibility Study. The publicmeeting was the initiation of a public comment period which closed onOctober 7, 1986. Each comment received during the public comment periodwas addressed in the Responsiveness Summary (Appendix B).

PREVIOUS STUDIES

As a result of the 1980 wastewater pond overflow incident, both EPA andFDER initiated separate studies of the Tower site. The FDER found thatwater with a low pH extended from the overflow area to Lake Apopka. InAugust 1980, the Florida Game and Fresh Water Fish Commission conducted astudy of the unnamed stream and Lake Apooka. Their results indicated thatthe fish population in the stream was below normal.

On August 12, 1980, EPA Region IV Environmental Services Division (ESD)conducted a site sampling investigation which included the main facilitydisposal areas, the unnamed stream, four private wells, and the sprayirrigation field. High concentrations of DDT and associated pesticidecompounds were found in samples collected from the main facility wastedisposal areas. The stream was determined to have been affected by chemicalsfrom the Tower site. Of the four wells sampled, one organic compound wasidentified in a sample from one well, but EPA suspected that this compoundwas the result of laboratory contamination. Some pesticide compounds werealso identified in soil samples from the spray irrigation field. InFebruary 1981, three of the four residential wells were resampled and theanalytical results revealed no presence of organic compounds.

In 1981, FDER collected samples from the spray irrigation field and themain facility disposal areas. The soils at the spray irrigation field werefound to be contaminated by pesticides primarily within the upper foot ofsoil. Higher levels of pesticide contamination were identified at theburn/burial area and at greater depths. A geophysical survey was alsoperformed at the main facility as part of the FDER study. The reportissued by FDER indicated a possible groundwater contamination problem caused

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TOW 002086

by mounding effect of the ground water beneath the former wastewater pond.EPA's Contractor, NUS Corp. recommended further hydrogeo logical investigationwith the concern focusing on a possible hydraulic connection between thesurficial and Floridan aquifers.

In 1982, FDER collected several ground water samples from temporary sandpointwells set just below the water table. These analytical results indicatedthe presence of DDT and dicofol in the ground water. Later the same year,the FIT contractor for EPA (Ecology & Environment, Inc.) attempted ageophysical survey at the site with limited success, presumably due to verydry soil conditions.

Also in 1982, EPA/ESD conducted an ambient air sampling investigation tosupport the site's HRS score. The Tower Chemical Company was not inoperation at the time of the study. The results of the investigationindicated that there was not an ambient air quality problem in the vicinityof the main facility.

In April 1983, the Centers for Disease Control (CDC) recommended sitestabilization and access restriction to the main facility disposal areas.This recommendation lead to the authorization and implementation of animmediate removal measure in July 1983. Following the removal activites, aRemedial Action Master Plan (RAMP), was developed for the site but the RAMPitself did not entail field work.

PREVIOUS SITE RESPONSE ACTIONS

Following the closure of the Tower Chemical Company, FDER requested assistancefrom EPA to implement remedial action at the site. The main facility wasfurther sampled and an immediate removal measure (IRM) was conducted by EPAin July 1983. FDER maintained the lead authority for the removal worknecessary at the spray irrigation field. Descriptions of the IRMs follow.

Main Facility IRM; The Centers for Disease Control Agency for ToxicSubstance and Disease Registry (CDC/ATSDR) determined that a potentialthreat to public health existed at the Tower site due to the potential forexposure to wastes in the main facility area. Field studies identified a2,275 square foot area that comprised the burn/burial area. This area wasexcavated to an average depth of 8 feet, where previously elevated levelsof pesticides diminished. At a depth of 5 feet, approximately 70 emptydrums and 2 partially filled drums were unearthed. All of these excavatedmaterials were shipped to the Chemical Waste Management facility in Emille,Alabama for disposal.

Simultaneous with the excavation activities, water was pumped from thepercolation/evaporation pond. The wastewater was treated on-siteto levels which complied with existing laws by use of an activated carbonfilter and pH adjustment.

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TOW 001 002087

The treated wastewater, which had been verifed for release, was dischargedinto the unnamed stream north ot the site, and thereby into Lake Apopka.Approximately 1,000,000 gallons of contaminated water were treated anddischarged. Once the water level in the percolation/evaporation pond waslowered sutticently, excavation ot the contaminated sediments began. Thesediments were dewatered ana bulked with the excavated soils before beingshipped to Bnille, Alabama. Approximately 1,545 cubic yards of contaminatedsediments were removed from the site.

After the removal activity was completed, both the burn/burial area and thepond were backfilled with clean fill material. The excavated portion otthe burn/burial area was covered with a clay cap. A surface water run-offdiversion system was installed to reduce the amount ot precipitation wnichcould percolate through the former pond area. Finally, a chain link fencewith a locking gate was erected around the perimeter of the two disposalareas .

Spray Irrigation Field IRM; In 1981, FDER ordered O.T. Enterprises, theproperty owner, to clean-up the spray irrigation field. This clean-up wasto consist of removal of the contaminated soils around each sprayhead anddisassembly of the system. The PVC lines and sprayheads were removed andapproximately 1.5 feet of soil were removed from the defoliated areassurrounding each sprayhead. This soil reportedly was placed on the westside of the west pond. The remaining soil was then tilled and limed.Other reports suggest that the spray irrigation field was disced and limedonly, and that no soil was removed (Hubbard, 1984). With this uncertainty,the spray irrigation field was addressed as part of the RI/FS.

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TOW 001 002088

SECTION III 'CURRENT SITE STATUS

The physical characteristics of the Tower Chemical Company site wereevaluated during the Remedial Investigation (RI) process. As a result ofthe RI field study the current status of the site has been well defined.In order to understand the current site conditions it is necessary to knowwhat compounds were historically used on the site. This information ispresented in Appendix C.

SOILS

Main Facility Soils

The soil samples collected in the area of the main facility were obtainedfrom both surface and subsurface sampling points from five areas which weredefined by drainage pathways (Figure 4). The five areas are:

The east drainage fieldThe north burn/burial drainage areaThe south burn/burial drainage areaThe former pond overflow area, andThe main building drainage area

Surface soil sample locations are shown in Figure 5. The locations ofsubsurface soil samples collected at depths of 2 feet are shown in Figure6 and those collected at depths of 7 feet are shown in Figure 7.

Analysis of the surface soil samples indicated that the compounds listedin Table 1 were present in significant quanitities compared to thebackground samples. The compounds identified in these analyses arereflective of the known historical operations at the Tower Chemical Companysite. The analytical results of the two-foot and seven-foot subsurfacesoil samples are shown in Tables 2 and 3 respectively.

The results of the main facility soil sample analyses show that the surfacesoils throughout the facility are. contaminated with 4,4'-DOT and itsderivatives, chemicals which are directly associated with the Tower ChemicalCompany's operation (Figure 8). Specifically, four areas were identifiedat the main facility that contained significantly elevated concentrationsof 4,4'-DDT and its derivatives in comparison to background levels (Figure9). These four areas are: the storage tank area next to the main building(to depths of less than 1 foot), the overflow area (to depths of less than

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1 foot), the drainage ditcn northeast of the burn/burial area (to depths ofless than 1 foot), and an area northeast of the entrance drive (to depthsof about 3 feet). The drainage area south of the burn/burial area wasfound to be contaminated with copper as well as other minor constituents.Subsurface soils in the burn/burial and former wastewater pond disposalareas also were found to contain elevated levels of site-related contaminants(Figures 10 and 11). Contaminants in the burn/burial area soils arelocated in the unsaturated zone while those in the former wastewater pondare already below the water table.

The horizontal extent of contaminated soil in the burn/burial arearoughly corresponds with the boundaries shown in Figure 12. Infiltrationthrough the contaminated unsaturated zone appears to be contributing togroundwater contamination ot the surficial aquifer. Dispersal ot contaminatedsurface soil was a problem in the past as evidenced by contaminated soilsin the receiving drainage areas. Since the former waste disposal areashave been covered, run-oft and erosion of contaminated soils appear tocurrently be only a minor concern.

The overall results of the RI revealed that only a small volume ot soils inthe main facility area exceed the clean-up criteria specified as part ofthe selected remedy (Appendix D). The areas which show contamination inexcess of the clean-up criteria are along the southwestern portion ot theburn/burial area, along the burn/burial area run-off zone, the overflowarea of the former waste water pond area, and the tank spillage area adjacentto the main building. The overall volume of these contaminated soils isapproximately 4000 cubic yards.

Spray Irrigation Field Soils

The soil samples collected from the spray irrigation field were alsocollected from surface and subsurface sampling points. The sample collectionarea consisted ot" four rectangular strips: Area 1, Area 2, Area 3S, andArea 3N. These four areas are based on the area affected by the toursprayheads used by the Tower Chemical Company for wastewater disposal.

Surface soil samples were collected from the points indicated in Figure 13and subsurface samples were collected at the points indicated in Figure 14.Subsurface soil samples were collected at depths of 2,3, and 4 feet. Due tothe homogeneous nature of the spray effluent, it was feasible to use compositesampling techniques. No surface samples were collected from Area 3N due tothe active presence of private regrading operations in which clean plantingsoils were added in that area during the field effort. An additionalcomposite surface sample was collected along the western boundry of thewest pond where excavated spraytield soils from the FDER IRM were reportedlystored.

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All control samples, Doth surface and subsurface, were collected from acitrus orchard which lies upgradient and west ot the spray irrigation tield.The nature of the contaminants found in the surface and subsurface soils atthe spray irrigation field can also be directly related to the operationsat the lower Site due to the presence of 4, 4 '-DDT and its derivatives. Acomparison ot selected contaminants tound in samples collected during the RIfrom surface and subsurface soils is presented in Table 4.

The surface soil sampling efforts revealed that soils could be transporteddowngradient if eroded, as shown in Figure 15, but it was demonstrated inthe RI Report that significant erosion is not occuring. The horizontalextent of surface contamination is generally expected to be as shown inFigure 16. Surface expression of the soil contamination is reflected bythe presence of stressed vegetation in the areas around the formersprayheads .

Analysis of the subsurface samples has indicated that contamination by 4,4'-DDT and its derivatives is detectable to depths of about 3 feet in Areas1,2, and 3S (Figure 17). In Area 3N, the spray line apparently was notused to any great extent during the Tower Chemical Company spray irrigationoperations because no contamination was identified in any of the subsurfacesoil samples collected in that area. No significant soil contamination wasfound along the west bank of the West Pand.

The remedial investigation showed that no contamination exists within thespray irrigation field in excess ot the established soil clean-up criteriator this site (Appendix D) . Therefore, soil contamination in the area otthe spray irrigation field is not of concern from either a public health oran environmental standpoint.

HYDROGEOLOGY

Groundwater Characteristics

Groundwater in the vicinity of the Tower Site occurs in the unconfinedsurf icial aquifer and the confined Floridan Aquifer (Figure 18). Thesurf icial aquifer extends over most of the site and is composed mainly ofquartz sand with varying amounts of clay and silt. Wells screened in thesurf icial aquifer are not used for domestic water supplies. Groundwater inthe Floridan Aquifer flows through solution channels and joint systems inthe limestone bedrock. The Floridan Aquifer is the major potable drinkingwater source in central Florida and many local residents have wells screenedin solution channels within the Floridan Aquifer.

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Surficial Aquifer. The surficial aquifer, in the area of the Tower ChemicalCompany site, flows generally to the northeast, towards the unnamed creek.The water table ranges from 0 to 20 feet below the land surface. Horizontalgroundwater velocity is estimated to be less than 2 feet per year over mostof the site, but a 150 foot area extending from the northeastern portion ofthe bum/burial area may have a horizontal velocity of 10 feet per year dueto localized mounding of the groundwater. Groundwater flow from the sitemay, in part, discharge into the unnamed creek north of the site andultimately reach Lake Apopka. Based on the field investigation, it is verylikely that a vertical component of flow exists from the surficial aquiferdownward into the Floridan Aquifer.

.Floridan Aquifer. The Floridan Aquifer, in the site area, is poorly confinedby the overlying Hawthorn Formation which is laterally discontinuous acrossthe Main Facility due to the presence of relic sinkholes. Groundwater inthe Floridan Aquifer moves rapidly through solution channels in anortheasterly direction. The top of the Floridan Aquifer ranges between 54and 188 feet below the land surface, with the potentiometric surface between5 and 10 feet below the land surface. Generally, the potentiometric surfaceof the Floridan aquifer imitates the topology of the surficial aquifer'swater table. The Floridan Aquifer is the primary drinking water sourcewithin the site area.

Analytical Results

Surficial Aquifer. Groundwater samples from the surficial aquifer werecollected in November 1984 and in March 1985 from 8 new monitoring wellsand 2 wells installed by the Tower Chemical Company (Figure 19). Samplescollected from the upgradient well, DS-01, provided background information.Two additional samples were collected to provide information on the groundwater quality in areas of high soil contamination: from the surface of thewastewater pond (a surface expression of the water table) and from groundwater which had infiltrated an excavation trench in the area of the formerwastewater pond.

Table 5 lists the contaminants of concern identified in the surficialaquifer at the main facility. The contaminants of concern were selectedbased on the overriding health and environmental risks posed by the compoundspresent, as determined in accordance with the Public Health Evaluation Manual,October 1986, and existing environmental laws.

The results of the groundwater sampling and analysis show that the surficialaquifer at the main facility is contaminated with xylene, ethyl benzene,gamma-BHC, chlorobenzilate, 4, 4 '-DDT with its derivatives and several othercompounds. Contaminant migration to the northeast has extended beyond theboundaries of the burn/burial area with possible contaminated groundwater

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discharge occurring into the ditch east of the facility (Figure 20).Vertically, contaminated ground water in the burn/burial area was identifiedat a depth of 35 feet in monitoring wells set on top of the Hawthornformation.

Activities from the Tower Chemical Company site did impact the surf icialaquifer groundwater in the vicinity of the main facility. Contaminantswere also detected at a depth of 60 feet beneath the former wastewater pondin the relic sinkhole. Migration of contaminants from the surficial aquiferis probably occurring via this relic sinkhole.

Samples collected from the area of the spray irrigation field indicatedthat there has been minimal impact on the surficial aquifer in that area,and no health criteria were exceeeded. Therefore, it was concluded thatthe wastewater spray irrigation practices of the Tower Chemical Company didnot significantly impact surficial ground water resources in the vicinityof the spray irrigation field.

Floridan Aquifer. Groundwater samples from the Floridan Aquifer werecollected fron a total of 12 private water supply wells and two newlyinstalled monitoring wells (Figure 21). Monitoring well MFW-01 was usedas a background well.

The analytical results of the groundwater samples collected from the FloridanAquifer indicate that Tower Chemical Company site has not impacted thegroundwater quality of the Floridan Aquifer. Of all compounds identifiedin samples collected from the Floridan Aquifer, the only constituent knownto have been used by the Tower Chemical Company is copper. However, theconcentration of copper found in the downgradient Floridan Aquifer samplesis similar to the concentration found in the sample collected from theupgradient well. Overall, it is believed that the operations associatedwith the Tower Chemical Company have not impacted the water quality of theFloridan Aquifer.

SURFACE WATER AND SEDIMENTS

Surface water and sediment samples were collected from the followinglocations in the site vicinity: the east ditch on the main facility, theunnamed stream north of the site, and the spray irrigation field ponds.

Surface Water

Surface water samples were collected from the points indicated in Figure 22The background surface water sample was collected fron a small pond withinthe swamp (SW-01); at a point unaffected by the Tower Chemical Companyoperations.

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Table 6 shows the concentrations of selected contaminants found in surfacewater samples collected from both the unnaned stream and the east ditch.It is obvious that 4,4-DDT and its derivatives were found in surface watersamples collected west of the main facility from the unnamed stream at theformer wastewater pond overflow point and east of the main facility in theeast ditch. Therefore, the nature of the contaminants in these two areascan be related to past activities at the Tower Chemical Company. However,as previously discussed, it appears that these contaminants may be theresult of groundwater discharge rather than the result of surface water run-off.

Table 7 shows all the contaminants found in the surface water samplescollected from the spray irrigation field ponds. As can be seen from thistable, all contaminants were at low concentrations and these contaminantsdo not appear to be related to Tower Chemical Company operations. Itappears that activities conducted in the spray irrigation field did notsignificantly impact the nearby ponds.

Sediments

Sediments samples were collected from the points indicated in Figure 23.The background sediment sample, SE-01, was collected from a small pondlocated in a swamp area which was unaffected by operations from the TowerChemical Company.

Table 8 shows the concentrations of selected contaminants from the samplescollected in the unnamed tributary and fron the east ditch. The concen-trations of 4, 4 '-DDT and its derivatives and metals in samples from theunnamed tributary were comparable to those found in the control sample andall of which are below action levels established in this Record of Decision.In contrast, the concentration of copper from the east ditch sample was50,000 ugAgr which is significantly higher than the -concentration found inthe control sample (5,000 ugAg)* The copper contamination can be relatedto operations conducted at the Tower Chemical Company. However, the concen-tration levels of copper contamination in the east ditch does not exceedthe health based clean-up criterion. Table 9 presents the maximum concen-trations of contaminants fran all samples collected from the ponds in thespray irrigation field area. The compounds identified in the irrigationfield sediment samples are not associated with operations from the TowerChemical Company. In any case, they do not significantly differ from thecontrol sample and are below established clean-up levels, thus the con-taminants do not present any significant health or environmental threat.

AIR INVESTIGATION

During the 1983 EPA removal action air quality monitoring stations wereestablished at the points shown in Figure 24. The monitoring conductedduring the 1983 removal activity indicated that the concentration of

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Table 7Maximum Concentrations of All Contaminants Found in

Samples Collected From Ponds in theSpray Irrigation Field Area.

Spray IrrigationParameter (ug/D Field Ponds

Bis(2-Ethylhexyl)phthalate

Acetone 503

Carbon Disulfide 23

Chromium 6

Lead 93

Zinc

Aluminum 410

Manganese

Iron 200

Sample Locations SY-02, SY-05

Estimated value.Material analyzed for but not detected.

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Table 9Maximum Concentrations of All Contaminanats Found in Pond Sediments

Spray Irrigation Field.

Parameter (uK/J)

Hexadecanoic Acid

Toluene

Barium

Cadmium

Chromium

Copper

Lead

Selenium

Vanadium

Zinc

Aluminum

Manganese

Iron

Sample Location*

ControlSoil

-

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650

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51,000

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particulate and volatile contaminants in the air did not differ significantlyoefore or during the excavation activity. The amDient. concentrations ofthe particulate and volatile pesticides in samples collected from the siteremained at levels between 1U~4 and 10~9 milligrams per cubic meter beforeand during the immediate removal. Excavation worn in the former disposalareas required personnel respiratory protection for those workers in theimmediate vicinity as a precautionary health and safety measure.

The air monitoring performed during the RI found no detectable levels ofcontaminants in the breathing zone except when five of the six monitoringwells at the main facility were opened and purged for sampling. Whileworking at these wells personnel respiratory protection was required becauseof the extremely elevated hydrogen sulfide concentrations. An ambienthydrogen sulfide problem was not detected.

ENDANGERED AND THREATENED SPECIES

There are no federally-listed protected plant species in Lake County. Ofthe State-protected plant species only Adder's tongue tern has been reportedas possibly existing in the vicinity of the site. This plant, whosescientitic name is Ophioglossum palmatum, is considered endangered by theState of Florida;

There are several Federally protected animal species within the area of theTower Chemical Company site. These endangered or threatened species arelisted in Table 10. Any remedial action taken at this site must includeconsideration of the potential impact that implementation could have onthese species.

A Natural Resource Damage Assessment was conducted for this site by theU. S. Fish and Wildlife Service (EVE). In this assessment, the FWS concludedthat the Tower Chemical Company site may have impacted the surroundingtrustee resources in a manner that threatens the ability of the area tosustain resident floral and faunal populations. However, after reviewingtne remedy being proposed for the Tower Chemical Company site, the FWSconcluded that the steps being recommended tor remediation will be sufficientto provide protection of the trustee resources (Appendix E).

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SECTION IVENFORCEMENI PROFILE

Initial notice letters were sent to all identified potentially responsibleparties (PRPs) on March 5, 1982. The recipients included Ralph Roane,President, Tower Chemical Company; James Gallagher, Trustee, GallagherLand Trust ("Trust"); and John Balnchard, owner, 0. T. Enterprises.Following issuance of the letters, a meeting was held on May 15, 1982 inEPA's regional offices in Atlanta, Georgia with all PRPs except RalphRoane present. At the meeting, representatives of the Trust committed toprepare a feasibility study to identify options for clean-up of the site.Following several requests for extentions of time by the Trust and repeatedmissed deadlines for providing the study, EPA, with the encouragement ofthe State of Florida, determined in June 1983 that an immediate removalaction was warranted.

On June 9, 1983, EPA Region IV issued a CERCLA Section 106 AdministrativeOrder to the PRPs requiring a surface clean-up of the site. The PRPsfailed to comply with the order and during June and July 1983, EPA RegionIV conducted a fund financed removal action at the site.

Prior to the commencement of the Remedial Investigation and FeasibilityStudy (RI/FS) at the site EPA again notified the PRPs and invited them toconduct or participate in the RI/FS. The PRPs failed to reply and EPAinitiated the RI/FS.

On June 30, 1984, EPA Region IV referred a Section 107 cost recovery caseto EPA Headquarters and to the Department of Justice. The complaint wasfiled in April 1985. The defendants named were those noted above. OnJune 5, 1986, an amended complaint was filed naming individual Trustmembers as defendants. A trial date had been set for June 1987, but thecase has been removed from the trial docket pending finaiization of aConsent Decree between EPA and several individual members of the GallagherLand Trust to partially reiirburse the Hazardous Substances Trust Fund forexpenditures related to the 1983 removal action.

To date, the PRPs have not made a proposal to undertake any responseactions at the site and, based on past performances, there is no reasonto believe that they will do so in the future.

TOW 001

002127

SECTION VALTERNATIVES EVALUATION

PUBLIC HEALTH AND ENVIRONMENTAL OBJECTIVES

Public Health Concerns

The public health threat posed by the Tower Chemical Company site, asidentified in the Risk Assessment (Appendices 0 and P, RI), is relativelyminimal. Several complete exposure pathways exist: ingestion ofcontaminated soils and surface water, physical contact with contaninatedsoils and surface water, inhalation of airborne participates, and potentialfor ingestion of contaminated groundwater via migration of contaminatedsurficial aquifer ground water into the Floridan Aquifer. The RiskAssessment found that the site currently appears to pose no significanthealth threat, but potential exposures are a risk. This was supported bythe CDC/ATSDR Public Health Evaluation (Appendix F).

Environmental Concerns

Discharge of contaminated ground water from the surficial aquifer intothe surface waters of the unnaned tributary north of the Tower site posesa potential environmental risk. The unnamed tributary discharges intothe Gourd Neck area of Lake Apopka and several federally protectedendangered or threatened species live within the range of the TowerChemical Caupany Site.

TECHNOLOGIES CONSIDERED

Several technologies were considered for remediating the Tower ChemicalCompany site. The technologies were presented in groups targeted atremediating a single aspect ot the site. Table 11 shows the technologiesconsidered for remediation of surface and groundwater contamination,technologies considered for remediation of soil contamination, andtechnologies responding to institutional controls.

Several combinations of technologies will provide remedial actions whichcomply with applicable, relevant, and appropriate environmental laws.However, preference was given to treatment technologies or resourcerecovery options which reduce the toxicity, mobility or volume of thewaste to the maximum extent practicable. Remediation of the site willrespond to issues raised under the Safe Drinking Water Act (SD/JA), CleanMater Act (CWA), the Resource Conservation and Recovery Act (RCRA).

TOW 001002128

Table 11. All Technologies Considered for Remedial Response at the TowerChemical Company Site.

GROUND WATER

Alternate Water Supply - Municipal Water Supply ExtentionAlternate Water Supply - Bottled WaterAlternate Water Supply - Individual Treatment Units

Ground Water BarrierGround Water RemovalGround Water Treatment

SURFACE WATER

0 Surface Water Removal0 Surface Water Diversion0 Point Source Runoff Diversion

SOILS AND SEDIMENTS

Surface Capping - Clay or Synthetic MembraneSurface Capping - Concrete or AsphaltSurface Capping - Soil MixturesExcavationSurface Soil/Sediment RemovalOn-Site DisposalOff-Site DisposalSoil Treatment - Soil Flushing/Soil WashingSoil Treatment - BiodegredationSoil Treatment - Activated CarbonSoil Treatment - Lime-Fly Ash Pozzolan ProcessSoil Treatment - Pozolan-Portland CementSoil Treatment - Thermoplastic MicroencapsulationSoil Treatment - MacroencapsulationSoil Treatment - Incineration

OTHER

No ActionMonitoringResident RelocationTanks and Concrete Pad RemovalSurface Regrading and Revegitation

-si-

TOW 001 O02i29

SCREENING OF TECHNOLOGIES

Potential remedial technologies identified for the Tower site werepre-screened on the basis of effectiveness and implanentability.For example, provision of bottled water to nearby residents was eliminatedduring the initial screening process because it fails to prevent dermalexposure to residents and because it creates a long term inconvenience toarea homeowners. Similarly, use of a concrete and asphalt cap waseliminated because the material is susceptable to cracking as it ages,thus reducing the effectiveness. Several treatment technologies werealso considered as required, including incineration and in situ treatmentsfor contaminated soils.

The next phase of technologies screening was based on a detailed reviewof each remedial alternative based on site specific criteria. The secondphase review considered the short-terra and long-terra aspects of effective-ness, implementability, and cost.

Technologies Eliminated

Several technologies were eliminated in the preliminary screening phaseand in the detailed screening (Table 12). The following is a list ofremedial options which were eliminated during the screening phases andthe reasons for elimination.

Alternate Water Supply - Bottled Water. Provision of an alternate watersupply was eliminated due to the personal inconvenience this option wouldcreate for homeowners near the site and because it fails to provideprotection against dermal contact with contaminants which could appear inthe water supply.

Surface Water Removal. Surface waters have not been significantly impactedoy past operations at the site based on existing applicable, relevant andappropriate standards, as a result, this activity is not necessary.

Surface Water Diversion. The unnamed stream north of the site has notbeen significantly impacted by the operations conducted by the TowerChemical Company as based on existing applicable, relevant and appropriaterequirements, nor does any portion ot the unnamed tributary pass throughareas of past activity. Therefore, surface water diversion is unnecessary.

Groundwater Barriers. Groundwater barriers act to prevent horizontalmigration of contaminated groundwater. Based on information collectedduring the RI, it is apparent that there is a notable vertical componentof groundwater flow downward through sink holes. Groundwater barrierswould therefore be ineffective at restricting migration of contaminants.

-52

TOW 001002130

Table 12. Technologies Eliminated During the Tower Chemical Company SiteScreening Process.

TECHNOLOGIES ELIMINATED

Ground Water Technologies

Alternative Water Supply - Bottled Water

Surface Water Removal

Surface Water Diversion

Ground Water Barriers

Soil Treatment Technologies

Soil Flushing/Soil Washing

Biodegradation

Activated Carbon

Lime-fly Ash Pozzolan Process

Pozzolan-Portland Cement Process

Thermoplastic Microencapsulation

Macroencapsulation

On-site Disposal

Concrete or Asphalt Cap

Soil Mixture Cap

No Action

REASON

Inconvenient to residents; doesnot prevent dermal exposure

Not warranted based on RI data

Not warranted based on RI data

Fail to prevent verticalmigration of ground water

High natural metals contentin soils prevents effectiveuse

Fails to address metalscontamination

Potential development of leachate;long term monitoring required

Expands material volume; increaseswaste disposal resource needs

Expands material volume; increaseswaste disposal resource needs

Increased cost without producinghealth or environmental gains;expensive

Increased cost without producinghealth or environmental gains;expensive

See text

High failure potential

High failure potential

Fails to address potential threatsto the public health, welfare andthe environment

-53-

T°W 002131

Soil Flushing/Soil Washing. This technology has been demonstrated to befeasible in soils which have low levels of naturally occuring metals,however, soils typical of this site have been shown to have very highlevels of natural aluminum and iron - several orders of magnitude higherthan that of the contaminants. As a result, the washing fluids wouldpreferentially remove the naturally occuring metals rather than the lowlevels of contaminants.

Biodegradation. Biodegradation does not address the metals contaminationfound at the site and would require long term operations before fullclean-up is effective. Other technologies, e.g., incineration, wouldprovide equal destruction efficiencies in a shorter time frame.

Activated Carbon. Although this technology has been proven effective fortreatment of both organics and inorganics in soils, it would require longterm monitoring to insure that no leachate develops from the site. Thisremedy was eliminated in favor of more permanent response options.

Lime-fly Ash Pozzolan Process. Although this process is effective inaddressing inorganic contamination, the volume of materials would increase,thus causing an increased disposal facility requirements. In addition,the soils being solidified contain significant amounts of organic compoundswhich could affect the integrity of the cement monolith. The presence oforganics will require containment of the monolith within an on-sitelandfill built above the land surface due to the locally high watertable. This technology would also require long-term (30 years) monitoringwhich is less favorable than technologies which provide permanentdestruction of wastes. Add other technologies are equally effective forsimilar costs.

Pozzolan - Portland Cement Process. Same as Lime-fly Ash Pozzolan Process.

Thermoplastic Hicroencapsulation. Although feasible, this option requiresspecialized equipment, trained personnel, and is expensive. Othertreatment technologies are equally effective and less expensive.

Macroencapsulation. Same as Thermoplastic Microencapsulation.

On-Site Disposal. While the volume and levels of contaminants arerelatively low, a high water table at the site makes it infeasible tosolidify or build an on-site landfill which meets the design specificationsoutlined in RCRA. It has been shown that the only feasible treatmenttechnologies available for this site, involve total destruction of thewastes, which takes in to consideration the preference for a permanentremedy as stated in Section 121 of SARA.

TOW 001 002132

Concrete or Asphalt Surface Cap. Tne risk of failure ot a concrete orashpalt cap is high due to the potential for fracture rormation.

Soil Mixture Caps, mis technology is unproven and has extensivemonitoring requirements. Development of dessication cracks could causefailure.

TECHNOLOGIES RETAINED

Several technologies were retained for final consideration as alternativesfor remediating the site. These individual technologies are listed inTaDle 13. In depth discussion of each technology can be found in the FS.

During the Feasibility Study process, the retained technologies weregrouped into remedial units which would accomplish specific remedialobjectives (Table 14). These remedial units were then combined todevelop full remedial alternatives which would respond to the conditionssurrounding the Tower Chemical Company site. A total of 8 comprehensiveremedial alternatives were designed from the various technologies retainedafter the screening process. Each of the possible alternativeswas analyzed based on effectiveness implementability and cost. A generalsummary of the concerns surrounding each technology is presented in Table15. It is important to note that the No-Action alternative is includedin the 8 alternatives considered for final remedy selection although itwas eliminated during the initial screening phase. The No-Action alternativemust be included at this point to tully ccmply witn the legal requirements.

Alternative Descriptions

Alternative 1 - No Action - Groundwater and Surface Water Monitoring.Under tne no-action alternative, no additional remedial activities wouldbe performed. Implementation ot* this alternative would not address theremediation of the site nor the potential threat to the public or theenvironment via the exposure pathways. However, the monitoringprogram would provide information so that possible adverse public healthor environmental impacts that might arise could be addressed. At theTower Site, early phasing of the groundwater/surface water monitoringprogram should be considered. Based upon the conclusions of the RemedialInvestigation (RI), groundwater contamination has been demonstrated in thesurficial aquifer which poses a potential threat to the Florida Aquifer.CAPITAL COSTS: $35,000 OPERATIONS AND MAINTENANCE COSTS: 965,000

w- -55-

T°W 0 0 1 002133

Table 13. Technologies Retained for FinalConsideration to Remediate theTower Chemical Company Site.

0 Ground Water Monitoring

° Municipal Water Supply Extention

0 Individual Treatment Units

0 Tanks and Concrete Pad Removal

° Point Source Runoff Diversion

0 Capping - Synthetic Membrane

0 Surface Regrading and Pevegetation

0 Surface Soil/Sediment Removal

° Ground Water Removal

0 Excavation

0 Water Treatment Technologies0 Soil Incineration

0 Off Site Disposal

-56-

TOW 001 002134

Table 14. Remedial Units and Objectives

Ground Water/SurfaceWater Monitoring

Ground Water Removal (MainFacility)/Individual TreatmentUnits Abater Treatment/Discharge

Municipal Water SupplyExtention

Establish base line data; identifychanges in the site conditions;determine effectiveness ofremoval actions

Prevent migration of groundwater contaminants and accidentalingestion of contaminated groundwater

Prevent accidental ingestion ofcontaminated ground water

Capping (Burn/Burial Area)/PointSource Runoff Diversion

Soil/Sediment Removal (N.E. ofMain Entrance and East Ditch);Water Treatment/ OffsiteDisposal

Soil/Sediment Removal (OverflowArea)/Point Source RunoffDiversion/Offsite Disposal

Surface Soil Removal/OffsiteDisposal

Soil Removal/Onsite Incineration

Tanks, Concrete Pads, andSoil Removal/OffsiteDisposal

Excavation (Former Waste WaterPond)/Point Source RunoffDiversion/Offsite Disposal

Excavation (Burn/Burial Area)/Point SourcE Runoff Diversion/Offsite Disposal

Soil Removal (Spray Field)/Offsite Disposal

Prevent direct contact with soils;reduce leachate to ground water;eliminate erosion of contaminatedsoils

Prevent direct contact with soils;eliminate erosion of contaminatedsoils

Prevent direct contact with soils;eliminate erosion of contaminatedsoils

Prevent direct contact with soils;eliminatte erosion of contaminatedsoils

Reduce surface soil contamination;remove source of groundwatercontamination; prevent directcontact with soils

Prevent direct contact withcontaminants; eliminate potentialthreat to ground water

Eliminate potential threat toground water and dermal exposureto soils

Eliminate potential threat toground water

Eliminate erosion of contaminatedsoil; prevent direct contact withsoils

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Alternative 2 - Ground Water and Surface Water Monitoring; Alternate WaterSupply - Municipal Water Supply Extention; Tanks, Concrete Pads, and SoilsRemoval. This alternative would include a monitoring program for groundwater and surface water and the extension of the Clermont municipal watersupply. Two tanks and seme concrete support pads which remain from theoperation of the Tower Chemical Company would also be removed. Theconcentrations and types of contaminants detected in ground water couldpose a potential threat to nearby private water supplies. Implementationof this alternative would eliminate this problem at the site, but thecontaminated ground water in the surficial aquifer would continue toremain a potential environmental problem. This option will also fail toaddress the threats posed by direct contact with contaminated soils. Theproposed monitoring program should be implemented first.CAPITAL COSTS: $546,000 OPERATION AND MAINTENANCE COSTS: $743,000

Alternative 3 - Ground Water and Surface Water Monitoring? Ground WaterRemoval (Main Facility) and Treatment; Alternate Water Supply - IndividualTreatment Units; Tanks, Concrete Pad and soil Removal. This alternativewould include the monitoring program described in Alternative 1, removaland treatment of contaminated groundwater, and the installation ofindividual treatment units on the two private wells adjacent to or on thesite. Two tanks and some concrete support pads which remain from theoperation of the Tower Chemcial Company would also be removed. Theremoval of contaminated groundwater would eliminate the potential formigration or ingestion. The treatment units would provide a protectedsource of potable water for the duration of the ground water removal.The monitoring program should be implemented in conduction with theground water extraction system. The individual treatment units could beinstalled while the monitoring wells are being constructed.CAPITAL COSTS: $3,523,000 OPERATION AND MAINTENANCE COSTS: $907,000

Alternative 4 - Ground Water and Surface Water Monitoring; Ground WaterRemoval and Treatment; Alternate Water Supply - Individual TreatmentUnits? Soil/Sediment Removal (Overflow Area); Exploration (Burn/BurialArea); Surface Soil Removal; Tanks and Soil Removal; and Tank/SoilsRemoval; On-Site Thermal Destruction of Contaminants in the Soils. Inaddition to monitoring, groundwater removal, water treatment, pointsource run-off diversion, removal of two process tanks, and excavationand on-site thermal destruction of soils from the overflow area, thisalternative would also address the concerns surrounding the bum/ burialarea. The point-source discharges from Vita-Green, Inc. would bediverted from these areas. Contaminated surface soils would be removed andexploration for buried drums in the burn/burial area would be conducted.Dewatering for excavation can be conducted simultaneously with the groundwater recovery operation.CAPITAL COSTS: $6,788,000 OPERATION AND MAINTENANCE COSTS: N/A

Alternative 5 - Ground Water and Surface Water Monitoringy Ground WaterRemoval and Treatment; Alternate Water Supply - Individual TreatmentUnits; Soil/Sediment Removal (Overflow-and Burn/Burial Areas); Excavation"(Former Waste Water Pond); Capping (Burn/Burial Area); Tanks/Soils Removal;

-Gl-

TOW 001 002139

and Off-Site Disposal of Soils. In addition to monitoring, groundwater"' removal, water treatment, and individual treatment units under this

alternative, contaminated soil would be excavated from the former wastewaterpond and a cap would be installed over the burn/burial area. Also, thesurface soils and sediments in the overflow area would be removed for off-site diposals. Excavation of the former wastewater pond should be imple-mented prior to the installation of the groundwater exctraction wells.Monitoring and groundwater removal could be implemented concurrently.CAPITAL COSTS: $10,293,000 OPERATION AND MAINTENANCE COSTS: $971,000

Alternative 6 - Ground Water and Surface Water Monitoring; Ground WaterRecovery (Main Facility) and Treatment; Alternate Water Supply - IndividualTreatment Units; Soil/Sediment Removal (Overflow Area); Excavation (FormerWaste Water Pond and Burn/Burial Area); Tanks, Concrete Pads, and SoiT"Removal; Tanks/Soils Removal. If this alternative were implemented, itwould be identical to Alternative #3 except that the burn/burial areawould be excavated and the two tanks, concrete pads, and soils would beremoved. These actions could be performed in conjunction with theexcavation of the former wastewater pond.CAPITAL COSTS: $15,440,000 OPERATION AND MAINTENANCE COSTS: $1,367,000

Alternative 7 - Ground Water and Surface Water Monitoring; Ground WaterRemoval (Main Facility) and Treatment; Alternate Water Supply - IndividualTreatment Units; Soil Sedijnent Removal (Overflow Area); Excavation (FormerWaste Water Pond and Burn/Burial Area); Tanks, Concrete Pad, and SoilRemoval; Point Source Run-Off Diversion; Surface Soil/Sediment Removal

\ > (East Ditch and Northeast of Main Entrance); Soil Removal (Sprayfield)and Soil Treatment Incineration. This alternative would tie similar toAlternative #6, except that surface soils would be removed from thesprayfield and an area northeast of the main entrance and the sedimentswould be removed from the east ditch. The soils removed from the sprayfieldwould be incinerated on-site and the treated soil used as backfill forthat area. Soil removal and soil incineration could be performedconcurrently with excavation or soil removal from the overflow area.CAPITAL COSTS: $28,219,000 OPERATION AND MAINTENANCE COSTS: $907,000

Alternative 8 - Ground Water and Surface Water Monitoring; Ground WaterRemoval (Main Facility) and Water Treatment; Alternate Water Supply -Individual Treatment Units? Soil/Sediment Removal (Overflow Area);Excavation (Former Wastewater Pond); Excavation (Burn/Burial Area);Tanks, Concrete Pads, and Soil Removal; Point Source Run-Off Diversion;Surface Soil/Sediment Removal (East Ditch and NE of Main Entrance); SoilRemoval (Spravfield) and Off-Site Disposal. If this alternative wereimplemented, it would be identical to Alternative 16 except that thesprayfield soils would be disposed of off-site.CAPITAL COSTS: $21,491,000 OPERATION AND MAINTENANCE COSTS: $907,000

ADDITIONAL CONSIDERATIONS

Since the enactment of the Superfund Amendments and Reauthorization ActLJ (SARA) new requirements have been enacted on the remedial response options

available for use at Superfund sites. Of these enactments, one portionof the Act has imposed stringent requirements which directly impact the

TOW 001 002140

selection of a viable remedy for the lower Oiemical site. This requirement(SARA Section 121 (b)) strongly opposes the selection of remedial actionswhich do not offer permanent solutions or which involve the disposal ofhazardous waste materials in landfills.

In order to respond to the "spirit" of this amendment, EPA commissioned astudy to further assess on-site soil treatment technologies. Thisevaluation is presented in Appendix G. A total of 9 soil treatmenttechnologies were assessed (Table 16). Of these technologies, none werefound to be acceptable based on the following aspects: effectiveness,implementability, and cost. These reasons have been previously discussedin the Technologies Eliminated portion of this section.

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T°W °01 002141

Table 16. Soil Treatment Technologies Assessed

9 Soil Flushing/Soil Washing

0 Biodegradation

0 Activated Caroon

0 Lime-Fly Ash Etozzolan Procees

0 Pozzolan-Portland Cement Process

0 Thermoplastic Microencapsulation

0 Macroencapsulation

0 Incineration

-64-

TOW 00100214^

SECTION VICOMMUNITY RELATIONS

Community relations efforts for the Tower Chemical Company site wereinitiated in September 1984 when EPA completed the site Community DelationsPlan. Area residents were contacted as part of the community relationswork. Overall, area residents expressed concern tor both health and non-health issues. However, the conminity interest overall, in this site hasbeen limited.

An information repository was established at the Cooper Memorial Liorary,near the site. All final documents, plus the dratt Remedial Investigation(RI) and draft Feasibility Study (FS) were sent to the repository toprovide Public access.

In preparation for the public meeting, a tact sheet was sent to theinterested parties listed in the Community Relations Plan. The factsheet provided interested parties with a summary of all remedial alternativesbeing considered by EPA for remediating the problems surrounding theTower Chemical Company site. On September 16, 1986, a public meeting washeld to discuss the findings of the RI/FS. The public meeting served toinitiate a 3 week public ccmment period which closed on October 7, 1986.Attendance at the public meeting was moderate. Several written commentswere received during the public comment period. These comments have beenfully addressed in the Responsiveness Summary (Appendix B), which wasalso placed in the information repository.

TOW 001 002143

SECTION VII^ CONSISTENCY WITH OTHER ENVIRONMENTAL LAWS

Other envirorrnental laws which may be applicable or relevant to therernedial activity being proposed for the Tower Chemical Company site are:

— Safe Drinking Water Act— The State of Florida Administrative Code (FAC);

Chapter 17-3 - Surface Waters: General Criteria— The State of Florida Administrative Code (FAC);

Chapter 17-22 - Drinking Water Standards— The State of Florida Administrative Code (FAC);

Chapter 17-30 - Hazardous Waste— EPA Ground Water Protection Strategy— Clean Water Act (CWA)— St. Johns Water Management District: Extraction

Well Permits— Resource Conservation and Recovery Act (RCRA)— Executive Order 11988: Floodplain Management

Locally, residents obtain their water supplies from the Floridan Aquifer,which is poorly protected in the site vicinity due to the presence ofrelic sinkholes. Therefore, the mandates of the Safe Drinking Water Actapply to this site. The use of temporary water treatment units on the

ij two private wells nearest the site will insure that the well users will^"* have safe drinking water supplies until the aquifer can be fully restored

by the ground water recovery and treatment activity. Ground water clean-up operations are consistent with the goals established in the EPA GroundWater Protection Strategy (GWPS); failure to respond to ground watercontamination could threaten the local drinking water supply — theFloridan Aquifer, and would lead to degradation of the surficial aquifer.Also, the GWPS seeks further to protect environmentally sensitive areassuch as the nearby wetlands.

The recovered ground water would be treated before being discharged tothe unnamed stream north of the site. The discharge of this treated waterwill be conducted in accordance with the requirements of the Clean WaterAct, and in accordance with the requirements of surface water criteriaspecified in the Florida Administrative Code Chapter 17-3.061.3(m).

The ground water recovery operations will comply with the substantiverequirements which the St. Johns Water Management District may decide toimpose on ground water extraction wells through their permitting process.

The proposed remedy will eliminate all threats arising from the TowerChemical Company operations. As a result, there will be no requirementsunder RCRA for long term site monitoring.

Surface waters are not now being adversely impacted by the Tower Chemical, , Company site, however, failure to address ground water contamination will

TOW 001 002144

ultimately result in the discharge ot contaminated ground water into theunnamed creek north ot the site. Therefore, ground water recovery andtreatment operations are necessary to prevent eventual violation ot theFlorida Administrative Code Chapter 17-3.061.3(ra).

Destruction of the contaminated soils by incineration will nave to meetthe requiranents of Parts 264(o) and 261 Appendix 2 of RCRA, along withChapter 17-30 of the Florida Administrative Code. RCRA Part 264(o) governsall aspects of incinerator test burns, and RCRA Part 261 Appendix 2 governsthe EP Toxicity requirements for dispoals of incinerator ash. The Stateof Florida requirements governing incineration (FAC 17-30) adopts RCRAPart 264(o) without further state-imposed regulations. Therefore,incineration activities must be conducted in accordance with the applicableportions of RCRA.

The soil and ground water cleanup criteria (Appendix D) were jointlyestablished by EPA and FDER, based on the Superfund 'Public HealthEvaluation Manual.

The Natural Resource Carnage Assessment conducted by the Department of theInterior concluded that the operations of the Tower Chemical Company sitemay have impacted federally protected trustee resources (Appendix E).There are no wetlands currently being threatened by the site, nor willthe remedial action being proposed for this site create such a threat;however, failure to take remedial action at this site will eventuallycause the contaminants to invade all parts of the local ecosystem. Thesite is above the 500-year floodplain (Figure 25).

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TOW 001 00214G

SECTION VIIIRECOMMENDED ALTERNATIVE

SELECTED REMEDY

The recommended alternative for the Tower Chemical Company site consistsof removal and treatment of contaminated ground water, provision ofindividual treatment units for two private wells in the immediate sitevicinity, removal and incineration of contaminated surface soils frcmboth the overflow area and portions of the burn/burial area of the site,pilot excavation of the burn/burial area to determine the composition ofthe magnetic anomaly, removal of the two tanks, concrete pads, andcontaminated soils, and point source run-off diversion. This isAlternative 4, as outlined in Section V of this document.

The ground water recovery operation will require the removal of approx-imately 1UO,OUU,UUO gallons of contaminated water from under the site.The recovered ground water will be treated by a combination of flowequalization, chromium reduction, precipitation, filtration, and activatedcarbon processes in an on- site treatment facility as illustrated inFigure 26. Surface water discharge of the treated water will be thedisposal method used for this site. The ground water will be recovereduntil sampling efforts indicate that the criteria presented in Table 17are achieved, as fully as is possible given the current state-of-the-artanalytical capabilities. Prior to discharge of the treated effluent tothe surface water system, samples will be collected to confirm that theeffluent meets the clean-up criteria. The ground water recovery operationswill also serve to "flush out" mobile compounds which remain buried atdepth below the former wastewater pond.

Subsequently, a complete HSL scan will be performed to determine if thereare any remaining priority pollutants in elevated concentrations whichshould be addressed. Since primary and secondary drinking water standardscover only a small percentage of parameters on the list, all detectedpriority pollutants will be considered in evaluating whether furthergroundwater recovery and treatment will be necessary. The appropriatetlow rate and effective concentration limits will be evaluated anddetermined during the Remedial Design phase so that the surface watercriteria specified in Section 17-3 of the Florida Administrative Code arenot violated. This will provide assurance that surface water disposal ofthe treated ground water will not adversely impact the environment of theunnamed stream or Lake Apopka.

Individual water treatment units will be provided for two private wellsin the site vicinity to prevent potential exposure to ground watercontaminants should the contaminants migrate into the Floridan Aquiferprior to completion of the groundwater recovery action. The treatmentunits will be installed on the private water supply well being used byemployees of the Vita-Green Company, whose water supply well is on thesite property and to the well owned by Mr. Charles Hubbard, who is locatedimmediately adjacent to the site and whose water supply well is downgradient fron the contaminant plume. The individual treatment units will

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TOW 001002148

Table 17. Target Clean-up Levels for Ground Water Contamination at theTower Chemical Company Site

Florida Maximum TargetIndicator Ground Hater Observed Clean-upChemical Standard (ug/1) Concentration (ug/1) . Level (ug/1) Source

Arsenic 50 2,000 0.05 FACNickel NA 550 350 HAChromium 50 1,100 0.05 FAC

Alpha-BHC NA 0.21 0.05 MDLChloroform NA 2,000 5 MDLDDT NA ND 0.01 CAG

Chlorobenzilate NA 40 1.0 ACLDicofol NA 700 1.0 ACL

MCL - Maximum Contaminant Levels set by SDWAHA = Office of Drinking Water Health AdvisoryMDL = Minimum detection limit established for

the Contract Laboratory Program (CLP):provided for compounds which have 10~°health based criteria below detectionlevels

NA = No numerical standard existsFAC = Florida Administrative Code Chapter 17-3 j

Surface Hater: General CriteriaACL = Alternate Concentration Limit calculated

by the Region IV Regional Expertlexicologist; based on 10~6 health risklevels

-71-

TOW 001002149

Table 18. Target Clean-up Levels for Soil Contaminationat the Tower Chemical Conpany Site. Based on

human health risks.

Maxinum TargetIndicator Observed Clean-upChemical Concentration (tngAq) Level (mg/kq)

Copper 800 100Lead 600 100

Arsenic 8.4 5DDT 37 35

-72-

TOW °01 002150

become obsolete once the groundwater recovery operation reaches thespecified clean-up goals.

Surface soil removal will occur in the overflow area of the former wastewater pond, in portions of the the burn/burial area, and in the storagetank area where the Gop-o-Cide contaminated soils are found. Removal willcontinue until the soil clean-up criteria listed in Table 18 are reached.It is expected that approximately 40UO cubic yards of soils are contaminatedin excess of these clean-up criteria. After completion of the excavation,a confirmation soil sampling action will be conducted to confirm thesuccess of the removal operation.

Contaminated soils will be treated on-site by thermal destruction of thecontaminants. Hie remedial design phase will include a test burn todetermine optimun operating efficiencies for the thermal destruction unitand to determine the fate of the residuals. If the untreated residuals canmeet the RCRA de-listing requirements for hazardous wastes, the residuals willbe backfilled on-site. Conversely, if the untreated residuals fail to meetthe RCRA de-listing requirements, an appropriate treatment technology will beselected and applied to the residual materials.

Pilot excavation of the burn/burial area will be conducted in order toconfirm or negate anecdotal information that additional buried drums arelocated in that area. The excavation plan developed during the RemedialDesign will provide for proper destruction of any drum contents which maybe found during this activity using the same thermal destruction unit beingutilized for soil clean-up.

Point source run-off diversion will be designed to address the run-offemanating from the main building roof and Vita-Green washdown waters whichnow traverse the overflow area which are generated when the main buildingfloor is rinsed off. These waters will be diverted towards the unnamedstream. This activity will reduce the potential for erosion of the sitesoils. Revegetation and regrading of the overflow area, tank spillagearea, and the burn/burial area will also be considered as a necessarypart of this activity to minimize future erosion.

The two storage tanks which are left over from the Tower Chemical Companyoperations and nearby concrete pads will be decontaminated on-site. Thedecontaminate tanks will be recycled, and the decontaminated concretepads will be backfilled on-site. The first storage tank is located atthe northernmost corner of the main building and is in a vertical position.The second storage tank is located west of the burn/burial area and is in^ horizontal position. The concrete pads are along the northwestern wall

the main building.

Since this remedy will remove all contaminants of concern from the siteto levels below the established clean-up criteria, it will not be necessaryto undergo long term monitoring of the ground water or the surface water.Monitoring efforts will be limited to confirm tne success of the remedialaction and to assess the impact that implementation of the proposedremedy has on the surrounding area during the period of implementation.

-73-

TOW 002151

The selected remedy is expected to cost approximately 6.8 million dollars.The State of Florida has instituted a program for addressing the problemsposed by uncontrolled hazardous waste site. Tnis program is designed onthe CERCLA model and is operated similarly to Superfund through theFlorida Department of Env iromental Regulation. The State of Florida hasagreed to fund 10% of the cost for implementing the selected remedialaction (Appendix I). A summary of the cost estimate for the proposedremedy is presented in Appendix J.

Table 19 shows all alternatives evaluated fully for this site and thebasis on which each alternative is rejected.

STATEMENT OF COMPLIANCE WITH SECTION 121 OF SARA

The remedy proposed for the Tower Chemical Company site is the mosteffective alternative in terms of removing the threats posed by the site,and is considered the most effective choice given the current state ofclean-up technologies. This remedy is a Cost-effective remedy whichachieves a 10~6 public health protection level and will remove the threatsthis site poses to the environment. The remedy will provide protectionwhich will meet all applicable, relevant, and appropriate requirements,and is cost-effective. Finally, the remedy utilizes permanent treatmenttechnologies to the maximum extent practicable.

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, . SECTION IX*»r OPERATIONS AND MAINTENANCE

Operations and maintenance considerations for the selected remedy at theTower Chemical Company site will be limited. There will be no long termmonitoring related to the soils contamination since all soils whichexceed the clean-up criteria will be removed from the site. Once theground water removal operations are complete there will be no long termmonitoring required to monitor the groundwater quality. The groundwater removal operation will be permanently effective since there will nolonger be any soils to recent aminate the surficial aquifer or the FloridanAquifer. However, it is expected that any groundwater removal action isexpected to take an extended period of time depending on the design ofthe ground water recovery system.

It will be necessary to maintain the groundwater recovery system untilthe removal operations are complete, but this will be part of an ongoingremedial response. Under Section 121 of SARA, groundwater recoveryactivities are considered part of the Remedial Action for the first 10years of operation or until the groundwater recovery operation is complete,whichever occurs first.

EPA will provide O&M, if it later becomes necessary, for a period of oneyear, after which the State of Florida will assume responsibility for thesite.

TOW 00100215G

SECTION xPHDJECT SCHEDULE

The schedule for the RD/RA phases of the Tower Chemical Company siteremediation are dependent on the success of enforcement negotiations. Ifthe PRPs agree to undertake RD/RA, the schedule will be negotiated toacconcdate EPA, FDER, and the PRPS.

However, if negotiations with the PRP are unsucessful, EPA will followthe schedule outline below:

DateSchedule Landmark for

Implementation

1. Finalization of the ROD 06/30/87

2. Complete Enforcement Negotiations 08/15/87

3. Initiate Design 09/01/87

4. Complete Design 06/01/88

5. Award/Anend Superfund State Contract(and IAG) for Construction 07/01/88

6. Initiate Construction 07/15/88

7. Initiate Groundwater RecoveryOperation 07/15/88

8. Complete Construction 07/15/90

9. Complete Groundwater Recovery 07/15/93Operation

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TOW 001 002157

SECTION XIFUTURE ACTIONS

Successful implementation of the selected remedy will ultimately removethe Tower Chemical Company site from under the jurisdiction of theComprehensive Environmental Response, Compensation, and Liability Act(CERCLA) and as amended by the Superfund Amendments and ReauthorizationAct (SARA). Implementation of the selected remedy will provide a permanentsolution to the problems surrounding this site and will require no sub-sequent actions under CERCLA or SARA.

It will be necessary to confirm the efficency of the groundwater recoverysystem to insure that the concentration levels of mobile compounds in thecontaminated soils are being reduced to levels of no concern. The estimatedtime to remove all currently existing contaminated groundwater is 4 yearsafter initiation of the groundwater recovery system.

At the time that the groundwater recovery operation is completed, it willbe necessary to analyze the residual contaminant concentrations whichwill remain in the buried sediments below the former waste water ponds.The groundwater regime will be allowed to re-equilibrate for two yearsafter completion of the groundwater recovery operation. After two years,the groundwater in the vicinity of the former waste water pond will beresampled to identify the impacts, if any, which the residual soilcontamination will have on the groundwater environment.