21
US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared by U.S. Environmental Protection Agency Region 5 Chicago, Illinois Margaret/M. Guerriero ActingTJi rector Superfund Division 4^/ //, v>n D^:

US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

  • Upload
    others

  • View
    0

  • Download
    0

Embed Size (px)

Citation preview

Page 1: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

US lU'A HI.COKDS CI-.N 11.K RIXION S

508967

FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE

PICKAWAY COUNTY, OHIO

Prepared by

U.S. Environmental Protection Agency Region 5

Chicago, Illinois

Margaret/M. Guerriero ActingTJi rector Superfund Division

4^/ //, v>n D^:

Page 2: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

Table of Contents

List of Abbreviations and Acronyms 3 I. Introduction 4

FIVE-YEAR REVIEW SUMMARY FORM 5

II. Response Action Summary 5 Basis for Taking Action 5

Response Actions 6

Status of Implementation 6

Institutional Controls 7

Systems Operations/Operation and Maintenance 10

III. Progress Since the Last Five-Year Review 11 IV. Five-Year Review Process 12

Community Notification, Involvement, and Site Interviews 12

Data Review 12

Site Inspection 13

V. Technical Assessment 15 Question A: Is the remedy functioning as intended by the decision documents?.. 15

Question B: Are the exposure assumptions, toxicity data, cleanup levels, and Remedial Action Objectives (RAOs) used at the time of the remedy selection still valid? 16

Question C: Has any other information come to light that could call into question the protectiveness of the remedy? 16

VI. Issues/Recommendations 17 VTI. Protectiveness Statement 17 VIII. Next Review 17 IX. Appendix A - Reference List 18

Figure 1 Site Figure 19

Figure 2 Site Plan Map 20

Figure 3 Institutional Controls Map 21

Page 3: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

List of Abbreviations and Acronyms

CERCLA

EPA FYR IC ICIAP MCE MW NCP NPE O&M Ohio EPA PRP RA RAO RPM ug/E UU/UE

Comprehensive Environmental Response, Compensation, and Liability Act United States Environmental Protection Agency Five-Year Review Institutional Controls Institutional Control Implementation and Assurance Plan Maximum Contaminant Level Monitoring Well National Contingency Plan National Priorities List Operation and Maintenance Ohio Environmental Protection Agency Potentially Responsible Party Remedial Action Remedial Action Objective Remedial Project Manager Microgram per Liter Unlimited Use/Unrestricted Exposure

Page 4: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

I. Introduction

The purpose of a Five-Year Review (FYR) is to evaluate the implementation and performance of a remedy in order to determine if the remedy is and will continue to be protective of human health and the environment. The methods, findings, and conclusions of reviews are documented in FYR reports such as this one. In addition, FYR reports identify issues found during the review, if any, and document recommendations to address them.

The United States Environmental Protection Agency (EPA) is preparing this FYR pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Section 121, 42 U.S.C. § 9621, consistent with the National Contingency Plan (NCP) (40 CFR 300.430(f)(4)(ii)), and considering EPA policy.

This is the fifth Five-Year Review report for Bowers Landfill Superftmd Site. The triggering action for this statutory review is the signature date of the previous FYR. The FYR has been prepared due to the fact that hazardous substances, pollutants, or contaminants remain at the Site above levels that allow for unlimited use and unrestricted exposure (UU/UE).

The Bowers Landfill FYR was led by Dion Novak, Remedial Project Manager (RPM), EPA. Participants included representatives from the Ohio Environmental Protection Agency (Ohio EPA). Ohio EPA continues to take the lead for oversight of Operation &Maintenance (O&M) activities at the site under the 1996 State Consent Decree with the Potentially Responsible Parties (PRPs). The PRP group was notified of the FYR process and participated in the Site inspection as part of the review.

Site Background

Bowers Landfill is located in Pickaway County, at the junction of Island and Circleville-Florence Chapel Roads, 2.5 miles north of Circleville, Ohio (Figures 1 and 2). The site lies in the Scioto River flood plain and is L-shaped with its ends abutting the river.

The landfill is approximately 12 acres in size, 3,500 feet long, about 125 feet wide, and is situated ten feet above the surrounding grade. The current owner is CODB Hunt Club, based in Westerville, Ohio. Bowers Landfill began operation in 1958 and was closed in 1968. There was no activity at the site after 1968, except for unauthorized dumping of many large items such as appliances and used tires by individuals.

The surrounding area is rural, with some residences, and ponds to the east where quarrying occurred in the past. The Scioto River is west of the site and is used for boating, fishing and swimming. The landfill has been capped and the site is partially fenced, with posted warning signs.

The groundwater underlying the site flows toward and discharges to the Scioto River. No drinking water wells are located between the landfill and the river.

Page 5: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

FIVE-YEAR REVIEW SUMMARY FORM

SITE IDENTIFICATION

Site Name: Bowers Landfill

EPA ID: OHD980509616

Region: 5 State: OH City/County: Enter Cily/CountyPickaway

Lead agency: State [If "Other Federal Agency", enter Agency name]:

Author name (Federal or State Project Manager): Dion Novak

Author affiliation: US EPA Region 5

Review period: 1/29/2017 - 3/15/2017

Date of site inspection: 9/14/2016

Type of review: Statutory

Review number: 5

Triggering action date: 5/18/2012

Due date (fiveyears after triggering action date): 5/18/2017

11. Response Action Summary

Basis for Taking Action

Groundwater, surface water, sediment and soil were sampled at Bowers Landfill. It was determined that exposure to contaminated groundwater and soil, mainly via the ingestion pathway, were the principal threats to be addressed by the remedial action. Barium and benzene exceeded their respective Maximum Contaminant Level (MCLs) in groundwater at one monitoring well. However, groundwater down-gradient of the landfill is not used as a drinking water source. In addition, residential drinking water wells up-gradient of the site were sampled during the Remedial Investigation and showed no effects from the landfill.

A risk assessment of soil contamination indicated that the Hazard Index was exceeded using a worst-case scenario for ingestion of contaminated soil. In addition, the total cancer risk was 3 x 10'^, which represents an incremental increased cancer risk of 3 persons in 1,000,000.

Page 6: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

Despite the low levels of contamination, EPA determined that potential future risks were possible because the landfill was poorly covered, in some areas by less than a foot of soil. Additionally, EPA determined that site contaminants posed a threat as a result of frequent flooding.

Response Actions

The Record of Decision was signed on March 31, 1989. The remedy included capping, with gas, and groundwater monitoring to be conducted subsequent to capping, and deed restrictions to protect the remedy. The Remedial Design began in 1990 and was completed the following year. The Remedial Action (RA) began in 1992 and was completed in 1993.

The principal objective of the RA was to reduce the infiltration of precipitation into the landfill by installing a low-permeability clay cover. The RA for the site included removing surface debris and vegetation from the landfill, installing a low-permeability clay cover, constructing erosion control measures and drainage improvements, restricting site access and use, installing additional groundwater monitoring wells and a gas venting system, maintaining the clay cover after construction, and post-construction ground- and surface water monitoring.

Status of Implementation

During the RA, trees, brush, weeds and exposed/surface debris were removed. Most of the vegetation was burned. Old tires and appliances were decontaminated, removed from the site, and properly disposed of off-site. Landfilled material was kept on-site and placed so that it did not interfere with the capping process.

During the RA, eight additional monitoring wells were installed. Five of these wells were placed in the area west of the landfill. The remaining three were installed off-site on the west side of Island Road, about 1,500 feet south of the site. In addition, many of the established monitoring wells were installed in mounds and with risers to make access easier during flood events.

The gas venting system was installed in the grading layer, with the gravel layer placed around the header. Gases generated rise through the graded layer and are vented into the atmosphere.

The cover system included the following from bottom to top: grading and gas venting layer (one-foot-thick), low permeability clay cover (2.5 feet thick), and vegetated topsoil cover (3.5 feet thick).

The erosion protection and drainage improvements were accomplished by stabilizing the slopes of the site to promote drainage, installing sheet piling at the ends of the landfill abutting the Scioto River to stabilize the cap in that area, planting grass on the top and sides of the landfill, reducing the infiltration of surface water through the landfill by capping it, and reconfiguring the ditch system around the cap.

Page 7: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

Institutional Controls

Institutional controls (ICs) are non-engineered instruments such as administrative and/or legal controls that help minimize the potential for exposure to contamination and protect the integrity of the remedy. Compliance with ICs is required to assure long-term protectiveness for any areas which do not allow for UU/UE. The table below summarizes ICs for these restricted areas.

The ROD for the Site required ICs in the form of site access restrictions and deed restrictions prohibiting the use of groundwater in the landfill area and preventing disturbance of the landfill surface.

Pursuant to two consent decrees, one between the United States and the PR? group for the site, and a second between the State of Ohio and the PRP group, the site owner was required to record ICs in the form of deed restrictions for the site. See United States v. E.I, du Pont de Nemours et al. Civ. Action no. 2:91-CV-742 (S.D. OH, E. Div., December 14, 1993), App. D, "Deed Restrictions Applicable to the Site"; and Ohio v. E.L du Pont de Nemours and Co., et al. Consent Decree, Civ. Action no. C2 96-783 (S.D. OH, E. Div., September 16, 1996), App. D, "Deed Restrictions Applicable to the Site." The Bowers Deed Restrictions document provides a comprehensive list of land use controls to be observed by the landowner, and was intended to "run with the land," through a notice to successors in title in the event of a property transfer. The Estate of John N. Bowers appropriately recorded the Bowers Deed Restrictions document in 1996. See Estate of John N. Bowers, "Bowers Deed Restrictions," Instrument no. 9600008220, vol. 21, pp. 468-471, Oct. 16, 1996, Pickaway County OH, Recorder's office.

In 2006, the Bowers Estate transferred title of the Site to a holding company constituted by the estate agent, and the Bowers Deed Restrictions were transferred. See Ellen J. Bowers and Ben Kaptoff Ltd., "Corrective Executor's Deed," vol. 610, pp. 1369-1373," October 31, 2007, Pickaway County OH, Recorder's office.

In 2014, the property was sold to the CODB Hunt Club, LLC, and the deed restrictions were updated to conform with new state requirements for property use restrictions, Ohio Rev. Code §§ 5301.80 - 92. See CODB Hunt Club and Ohio EPA, "Environmental Covenant," vol. 692, pp. 1338-1350, January 30, 2014, Pickaway County OH, Recorder's office.

In 2016, an updated title commitment was completed for the site that confirmed that the deed restrictions were appropriately recorded and that they remain enforceable as a valid instrument under the State's rules. EPA continues to work with Ohio EPA to ensure the continued enforceability of the deed restrictions for the Bowers site. The table below summarizes ICs for each of the restricted area.

Page 8: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

Table 1: Summaty of Planned/Implemented ICs

Media, ICs ICs called Impacted IC Objective Title of Institutional Engineered Needed for in the parcels Control Instrument Controls and decision Implemented Areas that document Do Not Support UU/UE based on Current Conditions Landfill Site Yes Yes Site-wide Prohibits use Estate of John N. Area and Cap of land Bowers, "Bowers

underlying the Deed Restrictions," site for Instrument no. residential, 9600008220, vol.21. commercial, or pp. 468-471, Oct. 16, industrial uses; 1996, Pickaway allows limited County OH, recreational Recorder's office. use of land as described in As a result of the the transfer of property Environmental from the Bowers Covenant, estate to a holding while assuring company, the Bowers integrity of the Deed Restrictions landfill cap and were continued at the remedial site in Ellen J. components. Bowers and Ben

Kaptoff Ltd., "Corrective Executor's Deed," vol.610, pp. 1369-1373," October 31, 2007, Pickaway County OH, Recorder's office. [hereafter cumulatively referenced as "Bowers Deed Restrictions"].

This was replaced by CODB Hunt Club

Page 9: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

and Ohio EPA, "Environmental Covenant," vol. 692, pp. 1338-1350, January 30, 2014, Pickaway County OH, Recorder's office [hereafter "Environmental Covenant"].

RA Yes Yes Site-wide Assures Bowers Deed Components integrity of Restrictions and such as remedy Environmental Landfill gas components Covenant collection and venting system and monitoring wells Groundwater - current area that exceeds groundwater cleanup standards identified at the site. This area is immediately between the landfill and the Scioto River at monitoring well (MW) P-5B.

Yes Yes Site-wide Prohibits groundwater use until cleanup standards are achieved.

Bowers Deed Restrictions and Environmental Covenant

EPA's detailed mapping outlines the boundaries of the area covered by the Bowers Deed Restrictions and Environmental Covenant, and is found at Figure 3.

Current Compliance

Based on inspections and discussions with the site PR? group, EPA is not aware of site or media uses which are inconsistent with the stated objectives to be achieved by the ICs. The remedy is functioning as intended. No site uses which are inconsistent with the implemented ICs or remedy IC objectives were noted during the site inspection.

Page 10: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

Long-Term Stewardship

Long term stewardship requires continued compliance with the ICs consisting of land use and groundwater use restrictions to ensure that the remedy continues to function as intended. Long-term stewardship will ensure that the ICs are maintained, monitored and enforced. Ohio EPA approved the institutional control implementation and assurance plan (ICIAP) for the site in July 2016. This plan includes semiannual inspections of the remedy and annual inspections for IC monitoring. A title search was also completed in July 2016 that demonstrates compliance with the site ICs. The ICIAP Report is submitted annually to both EPA and Ohio EPA.

Systems Operations/Operation and Maintenance

The specific tasks that were listed for the anticipated 30 years of operation and maintenance (O&M) are as follows: 1) gas monitoring, 2) ground and surface water monitoring, 3) maintenance of the landfill cap, 4) site inspections, and 5) repairs.

The O&M activities for the site have been conducted by the PRPs consultant, Cummings/Riter Consultants Inc. They have also completed five annual monitoring reports since the last FYR. The latest annual monitoring event included the sampling and analysis of groundwater from six locations, surface water from three locations, a site inspection, and landfill gas monitoring. Surface water continues to be sampled and analyzed annually in the wetlands and the east ditch when those areas are not dry. Gas monitoring for methane and volatile organic compounds occurs on an annual basis. Other monitoring activities include minor repairs to the cap due to settlement and erosion, and regular mowing of the vegetative cap.

Barium and arsenic are currently the only constituents above their respective MCLs. Certain other inorganics are statistically elevated compared to background levels, but do not exceed MCLs or present any concern or threat.

Cummings/Riter Consultants Inc. has been using ChemStat by Starpoint Software to statistically analyze the data. In addition, beginning with the September 1998 sampling event, barium has been undergoing statistical analysis using the Sheward-CUSUM control chart. This analysis compares current sample results against the initial 1998 analysis.

As part of the continuing O&M, the site is monitored for evidence of trespassing, cap subsidence, and any potential impacts to groundwater or surface water from the landfill. Phase 6 of the site O&M began in 2015 with the approval of the Phase VI O&M Plan, and ground- and surface water monitoring will continue on the current schedule as outlined in this plan.

Animal burrow holes under well pads on the cap continue to require periodic filling. As the cover grasses matured and became thicker around the edges of well pads, the number and size of the bunows decreased. Normal settling under monitoring well pads was noted and repaired by addition of soil. Monitoring well tags have been replaced as needed. Minor repairs to the cap have been made as part of ongoing maintenance, including the repair of a large bare area along the northern slope of the cap. A small hole, minor erosion and evidence of animal burrowing

10

Page 11: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

along the northern slope facing the river were also repaired and re-vegetated during this reporting period.

Minor trespassing has been noted over the years, but since the change in property ownership, trespassing was not an issue during this reporting period.

III. Progress Since the Last Five-Year Review

This section includes the protectiveness determinations and statements from the last FYR as well as the recommendations from the last FYR and the current status of those recommendations.

Table 2: Protectiveness Determinations/Statements from the 2012 FYR

OU# Protectiveness Determination

Protectiveness Statement

OUl/site-wide Protective The remedy at Bowers Landfill protects human health and the environment. Exposure pathways that could result in unacceptable risks are being controlled. Institutional controls are in place and were verified as part of this review. Threats at the site have been addressed through capping of contaminated soils and landfill debris, the installation of fencing and warning signs, the implementation of ICs, drainage improvements and the installation of sheet piling to control erosion. In addition, maintenance is being performed on a regular basis to ensure that the monitoring wells, gas vents, and cap remain in good condition.

For the remedy to be protective in the long-term, the following actions need to be taken to ensure long-term protectiveness: ongoing implementation of the annual ground and surface water monitoring program. Current data indicates that barium is the only contaminant above the MCL. However, a conservative mass loading calculation concluded that the estimated in stream concentration of barium entering the Scioto River is below the Ohio EPA water quality criteria for barium within the Ohio River drainage basin. Levels of barium do not appear to be adversely impacting the Scioto River. In

11

Page 12: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

addition, there are no known residential well receptors between the site and the Scioto River where barium was detected. Ground and surface water monitoring will continue on the current schedule contained in the Phase V O&M plan.

Table 3: Status of Recommendations from the 2012 FYR

ou# Issue Recommendations Current Status

Current Implementation Status Description

Completion Date

OUI An IC monitoring plan, which includes the need to conduct a title commitment, needs to be developed to assure effective monitoring and maintenance of site ICs

Develop IC monitoring plan

Completed Institutional Control Implementation Plan approved by Ohio EPA. Updated title commitment completed.

July 2016

EPA requested an IC monitoring plan (ICIAP) and an updated title commitment be developed for the site, to ensure that existing ICs were being properly enforced and that the recent property transfer did not have any adverse impacts on the ICs protecting the remedy. This plan was approved by Ohio EPA in July 2016, which also confirmed that existing ICs are in place and protective of the site remedy.

IV. Five-Year Review Process

Community Notification, Involvement, and Site Interviews

A public notice was made available via a news release in the Circleville Herald on February 25, 2017, stating that there was a FYR and inviting the public to submit any comments to EPA. The results of this review and the FYR report will be made available at the site information repository located at the Pickaway County Public Library, 1160 N. Court St., Circleville, Ohio.

Data Review

In preparing this report, EPA reviewed all ground- and surface water data. Phase VI of the Site O&M began in 2015. The PRPs continue to conduct annual sampling for metals in groundwater and surface water, pursuant to the Phase VI Plan.

Barium continues to be detected over its MCL (2,000 micrograms per liter (ug/1)) at one monitoring well, MW P-5B, at concentrations ranging up to 2,250 ug/1 over the duration of

12

Page 13: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

reporting period. Arsenic was detected at slightly above its MCL (10 ug/1) at PW-5B (17.8 ug/1) and W-11 (11.7 ug/1) over the duration of the reporting period.

At the request of Ohio EPA, the effect of barium and arsenic concentrations reported in MW P-5B and W-11 continue to be evaluated using a conservative mass loading calculation from the Shewart-CUSUM control chart modeling. This calculation assumed that groundwater monitored in MW P-5B contributes base flow to the Scioto River. The latest calculation concluded that the estimated concentration of barium entering the Scioto River remains at 0.04 ug/1, which is well below the Ohio EPA water quality criteria for barium within the Ohio River drainage basin (1,000 ug/1). These calculations also concluded that the estimated concentration of arsenic entering the river is 0.000528 ug/1, which is well below the Ohio EPA water quality criteria for arsenic (10 ug/1) within the Ohio River drainage basin. These results continue to validate previous conclusions that barium and arsenic are not impacting the Scioto River at levels above regulatory standards. Barium and arsenic will continue to be assessed through the ongoing site monitoring program.

The ICs include the prohibition of site groundwater for drinking water uses, and ensure that there is no exposure to contaminated groundwater from the site. The level of barium in MW P-5B has fluctuated slightly over the years, at just above the MCL. The level of arsenic in MW-P-5N and W-11 has fluctuated over the last five years, and is just above the MCL. MW P-5B and W-11 are located between the landfill and the Scioto River within the area restricted from being used for residential wells. Since these locations are covered by the ICs, there are no groundwater receptors at these locations.

Site Inspection

The inspection of the Site was conducted on 9/14/2016. In attendance were Dion Novak, RPM, EPA; David O'Toole, Ohio EPA; Chad Coy and Mike Lambert, Woodard and Curran-PRP consultants; and Josh Culver and Chris Chappo, site owners. The purpose of the inspection was to assess the protectiveness of the remedy.

During the September 2016 site inspection, the monitoring wells, bumper posts, pads and gas vents were inspected. The grass cover, sheet piling and fencing were checked, as well as areas of the cap that have been previously repaired due to erosion of the cover. The cover itself is clear of brush and saplings. The access road to the landfill is in good condition. The wetlands/ponds are well covered in vegetation. The inlets to the ponds from the Scioto River are in good condition and are free of vegetation.

The sheet piling, monitoring wells, gas vents and fence are in good condition. The grass cover is in good condition. The PRPs have conducted repairs as needed, but such repairs have been minor, such as repainting of wells and gas vents, correcting areas of erosion, and filling in animal burrow holes. The PRPs will conduct additional minor cap repair in the spring in several areas where subsidence was discovered during the site inspection.

The fencing and gate securing the site were in good condition. Signs were posted at the entrance to the site and the access road was also in good condition. As the current site owner is on-site

13

Page 14: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

frequently, potential trespassing has been minimized.

Photographs from the site inspection are included below;

Entrance gate looking northwest

Landfill cap looking northwest

14

Page 15: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

Monitoring well W-11 looking southwest

V. Technical Assessment

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

Yes.

The remedy is operating and functioning as designed. The landfill cap continues to achieve the containment of waste and the prevention of the migration of precipitation to groundwater. ICs have prevented ready access to the landfill, and have prevented access to groundwater. A title

15

Page 16: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

commitment was completed and confirmed that the ICs remain protective and are in place. Fencing is in good condition and the warning signs are in place.

O&M has been effective. Animal burrowing has occurred around some of the monitoring well pads but continues to be repaired promptly upon discovery. While these burrows are shallow, they are refilled with soil and reseeded after each discovery. The grass cover is well maintained. Other maintenance, such as reseeding or repair of minor subsidence, is conducted as needed.

Barium concentrations in MW P-5B continue to be above the MCL. The results from the latest sampling data in 2016, showed barium in MW P-5B up to a concentration of 2,250 ug/1. This sampling also showed arsenic in two wells up to a concentration of 17.8 ug/1. However, there are no potential drinking water wells between the well locations and the Scioto River, and the area is covered by the site ICs, which prohibit groundwater wells in this area.

The effect of barium and arsenic concentrations reported in MW P-5B and W-11 continue to be evaluated using a conservative mass loading calculation from the Shewart-CUSUM control chart modeling. The latest calculation concluded that the estimated concentration of barium entering the Scioto River remains at 0.04 ug/1, and the estimated concentration of arsenic entering the river is 0.000528 ug/1, which are well below the Ohio EPA water quality criteria for barium and arsenic within the Ohio River drainage basin. These results continue to validate previous conclusions that barium and arsenic are not impacting the Scioto River at levels above regulatory standards. Barium and arsenic will continue to be assessed through the ongoing site monitoring program.

Question B: Are the exposure assumptions, toxicity data, cleanup levels, and Remedial Action Objectives (RAOs) used at the time of the remedy selection still valid?

Yes.

There have been no changes in the physical conditions of the site that would affect the protectiveness of the remedy.

There have been no changes in applicable or relevant and appropriate standards or "to be considered" standards that would apply to the Bowers Landfill site.

Land use has not changed near the landfill. No new exposure pathways or receptors have been identified. The remedy is progressing as expected.

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

No.

No additional information was discovered to call into question the protectiveness of the remedy.

16

Page 17: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

VI. Issues/Recommendations

No issues nor recommended actions were identified during this FYR.

VII. Protectiveness Statement

OUl and Sitewide Protectiveness Statement

Protectiveness Determination: Protective

Protectiveness Statement: The remedy at Bowers Landfill is protective of human health and the environment. Exposure pathways that could result in unacceptable risks are being controlled. ICs are in place and were verified as part of this FYR. Threats at the site have been addressed through capping of contaminated soils and landfill debris, the installation of fencing and warning signs, the implementation of ICs, drainage improvements and the installation of sheet piling to control erosion. In addition, maintenance is being performed on a regular basis to ensure that the monitoring wells, gas vents and cap remain in good condition.

For the remedy to remain protective, the annual ground- and surface water monitoring program should continue. Current data indicates that barium and arsenic are the only contaminants above their respective MCLs. However, a conservative mass loading calculation concluded that the estimated in stream concentration of barium and arsenic entering the Scioto River are below the Ohio EPA water quality criteria within the Ohio River drainage basin. Levels of barium or arsenic do not appear to be adversely impacting the Scioto River. In addition, there are no known residential well receptors between the site and the Scioto River where barium or arsenic were detected. Ground- and surface water monitoring will continue on the current schedule contained in the Phase VI O&M plan.

VIII. Next Review

The next FYR for the Bowers Landfill Superfund site is required five years from the signature date of this review.

17

Page 18: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

IX. Appendix A - Reference List

• 4"^ FYR report, May 18, 2012 • Record of Decision - March 24, 1989 • ICIAP report - December 2016 • Phase VI Data Summary Report - July 2016

18

Page 19: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

Figure 1 Site Figure

s c A L E

2000

«F£REMC£: 7.9 MM. U.S.O.& TOPOOmPHC MM* OF OH QUAOHMMIC. OATEOi 19M. PHOTOIIEViaEft tOTQ, SCALE; 1V2000'

nCURE 1 SrTE LOCATION MAP BOWERS lANOna CIRCLEVILLE. OH

MEPAIKD ran E.I. du PONT de NEMOURS AND CO.

WILMINGTON. DE AND

PPG INDUSTRIES. INC. PITTSBURGH. PA

Grn^ JxcomMmimmc

DRAWING NUMBER

93115A6 1 S-11-10 SITE LOCATMN MOICARM OMMN BVu a HEMACyr OATt g-24-»J

CHCCKEO B* fl SPICt/JX* OATfc «-«-« mvmoN DAHE CeSCMPDON APflWfO Bff: P. OTmrn mm

19

Page 20: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

Figure 2 Site Plan Map

'PfaoWfT"

20

Page 21: US lU'A HI.COKDS CI-.N 11.K RIXION S 508967US lU'A HI.COKDS CI-.N 11.K RIXION S 508967 FIFTH FIVE-YEAR REVIEW REPORT FOR BOWERS LANDFILL SUPERFUND SITE PICKAWAY COUNTY, OHIO Prepared

Figure 3 Institutional Controls Map

Institutional Control (10) Review Areas Depicting Required and Implemented Institutional Controls

Bowers Landfill Pickaway County, OH

Superfund U.S. Environmental Protection Agency

OHD980509616

Legend

Bowers Landfill Boundary

^ Landfill Cap- Required and Implemented IC

r /\ Land and Groundwater Use Restrirdions - Implemented 10*

* See Bowers Deed Reslric6or» (1996) for the restridion detais. Recorded at the Pickaway County, OH reconte'rs office.

EPAOM tease be adwMd tfiat araas depiolMi in tw map hay* been citimaM. The map dees not create any hgNsetrforoeabte by any party. EPA may retew or change Ms data and map at any bine.

ProdMMd by Sarah SaektMuse U.S.EPAR« -bnagtOate: U.S. EM Region S on

iterSoO

21