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THIRD FIVE-YEAR REVIEW REPORT
for
COKER'S SUPERFUND SITE
CHESWOLD,KENT COUNTY, DELAWARE
MAY 2009
Prepared by: U.S. Environmental Protection Agency
Region III ' ' Philadelphia, Pennsylvania
J. s J. Burke, Director Hazardous SIte Cleanup Division
klAY ;J, 2{ 2.£61 ' , Date .'
)
TABLE OF CONTENTS
List of Acronyms :.......................................•...................................................................... ii Executive Sum~maf)' iii Five-Year Review Summary Form ~ ~ iv I. INTRODUCTION ~ : 1 II. SITE CHRONOLOGy "2
Table 1 - Chronology of Site Events .2 III. BACKGROUND ~ 3
Physical characteristics ~ 3 Land and Resource Use..· ·.: : 3 History ·of Contamination ,
\
4 Initial Response Activities 4 Basis for Taking Action : · 4
IV. REMEDIAL ACTION IMPLEMENTATION 5 V. PROGRESS SINCE THE LAST FIVE-YEAR REVIEW 8 VI. FIVE-YEAR REVIEW PROCESS 8
Administrative Components : 8 Community Involvement : ; 9 Document Review ~ 9 Data Review 9 Site Inspection ~ ; 10
VII. TECHNICAL ASSESSMENT..............................................................•....................... 10
QuestionB: Are the Exposure A~sumptions Data, Cleanup Levels, and Remedial Action
Question C: Has Any Other Information Come to Light That Could Call into Question
Question A: Is the Remedy Functioning as Intended by the Decision Document? ........ 10
Objectives (RAOs) Used at the Time of the Remedy Selection Still Valid? ...... 10
the Protectiveness of the Remedy? 11 Technical Assessment Summary : 11
VIII. ISSUES ~ ~ 12 Table 2 - Issues 12
IX. RECOMMENDATIONS AND FOLLOW-UP ACTION 12 Table 3 - Recommendations and Follow-Up Actions - 12
X. PROTECTIVENESS STATEMENT ..............•............................................................ 13 XI. NEXT REVIEW 13
Figure 1
List of Acronyms
ARAR Applicable or Relevant and Appropriate Requirement
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
CFR Code of Federal Regulations
DNREC Department of Natural Resources and. Environmental Control
Easement Environmental Protection Easement and Declaration of Restrictive Covenants
EPA U.S. Environmental Protection Agency
GPRA Government Performance Results Act
GMUC
HHPA
Groundwater Migration Under Control
Long-Term Human Health ProteCtion Achieved
,
NCP National Contingency Plan
NPL National Priorities List
PRP . Potentially Responsible Party
RPM Remedial Project Manager
RAO Remedial Action Objective
RD/RA Remedial DesignlRemedial Action
RIIFS Remedial InvestigationlFeasibility Study
ROD Record of Decision
SWRAU Sitewide Ready for Anticipated Use
TBC To Be Considered
II
Executive Summary
The remedy for the Coker's Sanitation Service Landfills Site (Site) in Cheswold, Delaware included:
• Placing deed restrictions (institutional controls) on both landfill properties. • Enclosing the entire waste disposal areas of both landfills with a chain-link security
fence with a locked gate and placing warning signs along the fence. • - Placing cover material along the northern slope ofLandfill No.1 to eliminate
exposure to leachate seeps. . • Backfilling to grade and seeding areas of Landfill No.2 which had subsided due to
uneven settling of waste.. • Sealing leachate collection wells at Landfill No.2 with grout to reduce the potential
for direct contact with leachate. • Conducting ground water sampling semi-annually at both landfills. • Inspectingrthe landfills semi-annually during ground water sampling events. • Conducting surface water and sediment monitoring at the Willis Branch adjacent to
. Landfill No. 1at the same time as ground water monitoring for a period of no less than five years.
The assessment of this five-year review found that the remedy was implemented in accordance with the requirements of the Record of Decision (ROD). EPA finds that the remedy is protective of human health and the environment. All threats at the Site associated with exposure to contaminated soil, leachate or on-site groundwater have been addressed.
The Site·achieved construc"tion completion status with the signing of the Preliminary Close Out Report on September 29, 1993. This is the third five-year review for the Site. The first review was triggered by the date that onsite constructionbegan. The trigger for this five-year review was. the date of the completion date of the second review, May 25,2004.
GPRA Measure Review As part of~his Five Year Review the GPRA Measures have also been reviewed. The GPRA Measures and their status are provided as follows:
Environmental Indicators Human Health: Long-Term Human Health Pratec'tion Achieved (HHPA) Groundwater Migration: Groundwater Migration Under Control (GMUC)
'Sitewide RAU The Site is not Site-Wide Ready for Anticipated Use (SWRAU) but is expected to achieve SWRAU on December 30,2010. . .
..... III
Five-Year Review Summary Form )
I
SITE IDENTIFICATION I
.NPL status: X Final 0 Deleted 0 Other (specify)
Remediation Status (choose all that apply): Under Construction 0 Operating
* Complete
Multiple OUs? 0 YES .* NO Construction completion date: 9/29/1993
Has site been put into reuse? 0 YES X NO I
REVIEW STATUS
Lead agency: X EPA 0 State 0 Tribe 0 Other Federal Agency - -
Author(s) name: Ro'nnie M. Davis'
Author(s) title: Remedial Project Manager IAuthor(s) Affiliation: U:S. EPA - R'egion 3
Review period: 11/2008 - 512009
Date(s) of site inspection: 4/6/2009
Type of review: X Post-SARA oPre-SARA 0 NPL-Removal only Q . Non-NPL Remedial Action Site· Q NPL StatelTribe-lead Q ReQional Discretion
Review number: 0 1 (first) o 2 (second) * 3 (third) 0 Other(specify) .
, Triggering action: Q Actual RA Onsite Construction at Site Q Actual RA Start at OU# Q Construction Completion X Previous Five-Year Review Report o Other (specify)
Triggering action date:· 5/25/2004
Due date (five years after triggering action date): 5/25/2009 ' ,
Site name: : Coker's Sanitation Service Landfills Superfund Site
EPA 10: DED980704860
iv
Five-Year Review Summary Form, cont'd.
Recommendations and Follow-up Actions: Repair the chain link security fence. Monitor groundwater, surface water and sediments for
volatile organic compounds, semivolatile organic compounds and metals.
Protectiveness Statement: The remedy at the Site currently prot~cts human health and the environment. The chain
link security fences around the waste disposal areas of both landfills restrict access to the Site and reduce the potential for exposure to Site contaminants. The soil cover on the landfills prevents direct contact with the waste, minimizes migration of c0r:ttaminants to the groundwater, and reduces the generation of leachate. There is no evidence of erosion or a breach of the soil cover on either landfill. The closure of the leachate collection wells at Landfill No.2 has reduced the potential for direct contact with leachate. Thus, there ;s no known evidence of current exposure to the waste or Site contarniqants and the remedy is considered protective in the short-term. In the long term, the remedy is protect,ive because the deed restrictions (institutional controls) required by the ROD, which restrict the use of the land, have been implemented by the use of Environmental Easements. The institutional controls ensure long-term protectiveness by prohibiting any type of activi~y that could disturb the landfill surfaces or the underlying waste at each landfill, or in any way increase the risk of exposure to Site contaminants, including, but not limited to, any soildisturbing activities at the Site.
Other Comments: None
v
Coker's Sanitation ServiceLandfills Cheswold, Delaware
Third Five-Year Review Report EPA ID No. DED980704860
I. INTRODUCTION
The purpose of a five-year review is todetennine whether the remedy at a site is protective of human health and the environment. The methods, findings, and conclusions of reviews are documented in Five-Year Review reports. In addition, Five-Year Review reports identify issues found during the review, if any, and identify recommendations to address them.
. ,
The U.S. Environmental Protection Agency (EPA) is preparing this Third Five-Year Review report pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) § 121 and the National Contingency Plan (NCP). CERCLA §121 states:
Ifthe President selects a remedial action that results in any hazardous substances. pollutants, or contaminants remaining at the site, the President shall review such remedial action no less often than each jive years after the initiation ofsuch remedial action to assure that human health and the environment are being protected by the remedial action-being implemented. .In addition. ?fupon such review it is the judgement ofthe President that action is appropriate at such site in accordance with section [104} or [106} title, the President shall take or require such action. The President shall report to the Congress a list offacilities for whichsuch review is required, the results ofall such reviews, and any actions taken as a result ofsuch reviews.
EPA interpreted this requirement further in the NCP; 40 CFR § 300.430(f)(4)(ii) states:
Ifa remedial action is selected that results in hazardous substances, pollutants.' or contaminants remaining at the site above levels that allow for unlimited use and unrestricted exposure, the lead agency shall review such action no less often than every jive years after initiation ofthe selected remedial action.
EPA Region 3 conducted this five-year review of the remedy implemented at the Coker's Sanitation Service Landfills Site (Site) in Kent County, Delaware. This review was conducted by the EPA Remedial Project Manager'(RPM) of the Site, with assistance from the Delaware Department of Natural Resources and Environmental Control (DNREC), from November 2008 through May 2009. This report documents the results of the review.
This is the third five-year review for the Site. The triggering action for this review was the
completion of the second five-year review on May 25, 2009. This third five-year review is required because hazardous substances, pollutants, or contaminants remain at the Site above levels that allow for unlimited use and unrestricted exposure.
II. SITE CHRONOLOGY
Table 1 - Chronology ofSite Events
DATE ACTIVITY
1969-1977 Landfill No.1 operated at the Site.
1976-1980 Landfill No.2 openi.ted at the Site.
July 22, 1987 EPA placed the Site on the National Priority List ( NPL).
.December 30, 1987 \
Three PRPs signed an Administrative Order on Consent to. .
conduct the Remedial Investigation/Feasibility Study (RIfFS).
September 28, 1990 EPA issued a ROD.
April 8, 1992. EPA and six PRPs entered into a Consent Decree for implementation of the Remedial Design/Remedial Action (RDfRA).
July 1993 PRPs initiated construction activity.
September 9, 1993 EPA and the Delaware Department of Natural Resources and Environmental Control (DNREC) conducted the final inspection at the Site. .
September 29, 1993 EPA issued Preliminary Site Closeout Report.
1993 First groundwater sampling event.
2
DATE ACTIVITY-
1993- present On':going groundwater monitoring.
July 17, 1998 Site inspection for the First Five-Year Review.
January 6, 1999 First Five-year Review.
May 25,2004 2nd Five-Year Review.
December 18, 2008 Work Completion Report
February 19, 2009 Final Close Out Report \
April 6, 2009
-
Site Inspection
III. BACKGROUND
Physical characteristics
The Site is located near Cheswold in KentCounty, Delaware, approximately six miles northwest of the City of Dover. The Site consists of two landfills located approximately one-half mile apart on opposite sides of County Route 152. Landfill No.1, which is on the north side of Route 152, and Landfill No.2, which is on the south side of Route 152, are both partoflarger, heavily wooded tracts of land (Figure I). Properties adjacent to both landfills are primarily used for agricultural or residential development. Landfill No.1 is bordered on the north by a forested wetland that includes a shallow meandering stream, the Willis Branch of the Leipsic River. Agricultural lands border the tree lines east and west of Landfill No.2. Deer and other wildlife populate this area of Kent County. Groundwater in the vicinity of the Site is used for domestic purposes, including drinking water.
Land and Resource Use
The Site has been fenced off and is covered with grass, weeds, and trees. There have been no changes in physical features at the Site since the last five-year review. Several houses are located between the two landfills on Route 152.
/
3
(
History ofContamination
Both landfills were used for the disposal of process sludge. generated during the manufacture of latex rubber. Landfill No. 1 \yas a permitted landfill which began operating in 1969 and subsequently closed under the then-current state regulations in 1977. Approximately 45,000 cubic yards of solid waste were disposed of in six to eight feet deep, unlined trenches. Landfill No.2, which was also permitted, operated from 1976 to 1980 and also received approximately 45,000 cubic yards of waste. Sludge was disposed of in six feet deep, lined trenches that included a leachate collection system. The permit also required leachate collection and treatment, installation of groundwat~rmonitoring wells, regularly scheduled site inspections, and periodic groundwater and leachate monitoring. The trenches were capped with soil when the
. landfill was closed in 1980. As the waste in the trenches settled and stopped producing collectable quantities of leachate, leachate collection was phased out in the early 80's. Landfill No.1 is approximately t~n acres in size, and Landfill No.2 is approximately fifteen acres in size.
Initial Response Activities
The EPA conducted an initial Site Investigation in 1980, and a second one in 1983. Elevated levels of acrolein were found in one well and in one leachate collection pipe on Landfill No.2. Ethylbenzene was detected in the same well and le~chate collection pipe. Bis(2chloroethyl) ether was detected in two Landfill No. 1 leachate seeps.
Basis for Taking Action
Contaminants
Hazardous substances that have been detected in leachate, groundwater and waste atboth landfills include: .
Benzene Chloroform Ethylbenzene Styrene' Cresol Dibutyl Pthalate Phenol Cadmium Manganese
EPA placed the Site on the National Priorities List in July 1987. In April 1986, EPA issued letters to several Potentially Responsible Parties (PRPs) notifying them of their potential liability for Site response actions and inviting them to conduct the Remedial Investigation/Feasibility Study
4
(RI/FS). On December 30,1987, three PRPs signed an agreement with EPA in the form of an Administrative Order on Consent to conduct the RI/FS. The parties agreed"under a separate order, to remove drums containing varying quantities of latex waste found on-site during the RI.
Media investigation during the RI/FS included waste, leachate, groundwater, surface water and sediment, soil, and air. The waste at both landfills contained the highest number of contaminants and highest levels of contamination, primarily styrene, ethylbenzene, and phenolic compounds. Leachate from Landfill No.2 (taken from leachate collection trenches within the lined cells) contained the same contaminants, but at lower levds. The waste and leachate were determined to pose a threat to human health and the environment. Groundwater at both landfills contained similar compounds but at significantly lower levels, and it was determined that they did not pose a threat to human health or the environment.
IV. REMEDIAL ACTION IMPLEMENTATION
Remedy Selection
EPA issued a ROD for the Site on September 28, 1990. The major/components of the selected remedy include deed restrictions to limit access, increasing the cover material to eliminate exposure and grouting the leachate collection system to reduce the potential for direct contact. The waste materials found in the landfills at the site is neither liquid nor highly mobile, and can be reliably controlled in place. EPA and the State determined that onsite containment ofthe waste is an appropriate remedial action.
The goal ofthe remedial action objective is to limit exposure to Site contaminants by covering the landfills and limiting access to the material in the landfills. The goal of the remedial action for the Site is to reduce the potential for future contact with the waste or with Site contaminants, thereby reducing risks to within EPA guidelines. The cancer risks associated with no action at both landfills is at or above EPA's guideline of 1 x 10-4; after implementation of the selected remedy, cancer risks are below 1 x 10-6
•
The Hazard Index score for children at Landfill No. hvas 3.26, which exceeds EPA's preferred guide line of 1.0. The Hazard Index scores for adults and children at Landfill No.2 were 48 ~nd 156, respectively. Following the implementation of the remedy, the Hazard Index score has been reduced to below 1.0 at both landfills.
Because there are no users of g'round water hydraulically downgradient of Landfill No.1, monitoring of Landfill No.1 was conducted primarily for the protection of aquatiC life in the Willis Branch. The trigger levels developed for each of the site related contaminants of concern for ground water are as follows: styrene (2900 ug/L), and ethylbenzen (3,200 ug/L). The trigger levels for surface water for surface water monitoring are as follows: styrene (1,400 ug/L), ethylbenzene (1,600 ug/L), and xylenes (900 ug/L. Sediment samplin'g coincided with surface water sampling and used to aid- in the evaluation of surface water data and site conditions.
5
Because a few residential wells are located hydraulically downgradient of Landfill No 2, monitoring at Landfill No.2 has been conducted primarily for the protection of human health. The trigger levels developed for each of the site-related contaminants of concern for ground water at Landfill No.2 are as follows: styrene (100 ug/L), ethylbenze (5 ug/L), 1,2,3-trichloropane (5 ug/L), phenolics (22,999 ug/L), and antimony (6 ug/L).
Remedy Implementation
On April 8, 1992, the State, EPA, and the PRPsentered into a Consent Decree for implementation of the Remedial Design/Remedial Action for both landfills.
The following is a summary of the remedial action (set forth below in italics) required by the ROD, followed by the activities (set forth below in regular type) that have been conducted at the Site pursuant to the ROD, and which are described in more detail in the Preliminary Site Close Out Report.
• Deed restrictions (institutional control!» will be placed on both landfill properties • An Environmental Protection Easement and Declaration of Restrictive
Covenants between Alberta Schmidt, as Grantor, and DNREC, on behalf of the State of Delaware, as Grantee, relating to Landfill No.2 was signed on ,February 24,2005. The documentwas recorded with the Office of the Recorder of Deeds for Kent County, Delaware on April 18, 2005 to implement the institutional controls for LandfillNo.1.
-• An Environmental Protection Easement and Declaration of Restrictive
Covenants between Kowinsky Farms, Inc, as Grantor, and DNREC, on behalf of the State of Delaware, as Grantee, relating to Landfill No.2 was sign~d on September 24,2008. The docul)1ent was recorded with the Office of the Recorder of Deeds for Kent County, Delaware on November26, 2008 to implement the institutional controls for Landfill No.2.
• The entire waste disposal areas ofboth landfills will be enclosed by a chain-link ~'ecurity fence with a locked gate to restrict the access ofunauthorized persons and equipment onto the landfills. Appropriate warning signs will be placed along the j(mce, Six foot chain-link security fences were placed around both landfills and warning signs were placed around the fences..
• Cover material will be placed along the northern slope ofLandfill No, 1 to eliminate exposure to leachate seeps. Mulch was placed along the northern slope of Landfill No. 1 to cover e~posed leachate seeps. The cover was graded to conform with the existing drainage patterns.
• Areas ofLandfill No.2 which have subsided due to uneven settling ofwaste will be baclifilled to grade and seeded. The subsided areas, as well as other portions of the
6
I
landfill surface, were covered with soil and graded as needed to promote surface drainage. Following re-grading, the landfill surface and other disturbed areas were seeded and mulched to prevent erosion.
- Leachate collection wells at Landfill No.2 will be sealed with grout to reduce the potential for direct contact with leachate. The vertical sections of the leachate collection wells were plugged with bentonite and filled to the existing ground surface with grout. Following sealing, the portions 6fthe pipes that were above the
. ground surface were removed, and the landfill s~rface re-graded.
• Groundwater will be sampled semi-annually at both landfills. Three wells were sampled at Landfill No. I and four at Landfill No.2. The sampling parameters were ethylbenzene, styrene, 1,2,3-trichloropropane, antimony, and phenolics, as well as field parameters. Groundwater was sampled semi-annually in 1993 and 1994, and annually thereafter until 1999. No contamination was found in the groundwater at Landfill No.1. Phenolics were found in several wells at Landfill No.2, but at concentrations three orders of magnitude below the action level. Groundwater monitoring was discontinued based on the recommendation to do so in the First Five-Year review. During the preparation and completion of the Final Close Out Report in February 2009, EPA deCided monitoring should resume at a minimum of every five years because waste has been left in place at the Site,
-The landfills will be inspected semi-annually during groundwater sampling events. The Site has been inspected regularly as required in the ROD and routine, .
maintenance activities have been performed as needed. The routine maintenance activities have generally consisted of minor fence repairs, replacement of warning signs, and mowing the surface of Landfill No.2.
- Surface water monitoring will be conducted at the Willis Branch adjacent to Landfill No. 1 at the same time as groundwater monitoring for a period ofno less than five years. Three sampling locations, were selected in the Willis Branch (one upstream, one adjacent to, and one downstream of Landfill No.1). The selected
. parameters were ethylbenzene, styrene, and total xylene, as well as field parameters. No contaminants were detected in the surface waterduring any sampling event. During the first sampling event, xylene was detected in the upstream sediment sampling location. The concentration was low, and thi~ compound was not detected in any subsequent sampling event. Surface water and sediment monitoring was discontinued based on the recomJ11endation to do so in the First Five-Year review. During the preparation and completion of the Final Close Out Report in February 2009, EPA deci,ded monitoring should resume at a minimum of every five years because waste has been left in place at the Site, ,
7
On September 9,1993, EPA and DNREC conducted the tinal construction inspection. On September 29, 1993, EPA signed the Preliminary Site Close Out Report, which documented that the PRPs had completed construction activities at the Site.
V. PROGRESS SINCE THE LAST FIVE-YEAR REVIEW
An Environmental Protection Easement and Declaration of Restrictive Covenants between .Alberta Schmidt, as Grantor, and DNREC, on behalf of the State of Delaware, as Grantee, relating to Landfill No.2 was signed on February 24,2005. The document was recorded with the Office of the Recorder of Deeds for Kent County, Delaware on April 18,2005 to implement the institutional controls for Landfill No.1.
An Environmental Protection Easement and Declaration of Restrictive Covenants betw'een Kowinsky Farms, Inc, as Grantor, and DNREC, qn behalf of the State of Delaware, as Grantee, relating to Landfill No.2 was signed on September 24,2008. The document was recorded with the Office of the Recorder of Deeds for Kent County, Delaware on November 26,2008 to implement the institutional controls for Landfill No.2. .
The PRPs' submitted the Work Completion Report on December 18, 2008, which summarizes all of the work completed at the Site. The Final Closeout Report was signed on February 19,2009, and EPA will prepare the Notice ofIntent to Delete, pending the results of the planned' sampling event. .
, .
The PRPs' mow the grass once a year at landfill No.2.. Also, they submitted a five year monitoring report in April 2009. This monitoring report includes groundwater, surface water, and sediment monitoring results from monitoring events conducted on March 21 and March 22, 2009. These were the first sampling events following the completion of the Final Close Out Report.
,
VI. FIVE-YEAR REYIEW PROCESS
Administrative Components
EPA notified DNREC in December 2008 of the initiation of the five-year review. The fiveyear review team was led by Ronnie M, Davis, the EPA Remedial Project Manager (RPM) for the Site. Steve Johnson of DNREC assisted in the review as the representative for the support agency.
The five-year review schedule included the following components:
• Community Involvement;
• Document Review;
8
• Data review;
, • Site Inspection; and
• Five-Year Review Report Development a'nd Review..
Community Involvement
Carrie Deitzel, EPA's Community Involvement Coordinator, informed local officials that EPA was conducting the
l Five-Year Review. EPA will place a public notice in the Delaware State
News, after the yd Five-Year Review is signed, to inform the public that the Five-Year Review has been conducted and that the findings are available.
Document Review
The following documents were reviewed for this Five-Year Review:
• Consent Decree (entered by the Court on April 8, 1992)
• Second Five-Year Re~iew Report (May 25, 2004)
• Final Closeout Report (February 19,2009)
• Coker Sanitation Services Landfills 0 & M Progress Report ( 2009)
• \york Completion Report (2008)
Data Review
Sampling for ethylbenzene and styrene were approved in the sampling and analysis plan and monitored during the 2009 sampling ev~nt at landfill No.1. Neither parameter was detected in the ground water. .
Sampling for ethylbenzene, styrene, I,2,3-tricloropropane, antimony, and total phenolics were approved in the sampling plan and monitored during the 2009 sampling event at landfill No. 2. Ehylbenzene, styrene, and phenolics were not detected in the ground water; and antimony was below the trigger level of 6 ug/l.
Three parameters were analyzed in surface water and sediments:' ethylbenzene, styrene, and xylenes (total). None of the parameters were detected in surface water or sediments.
9
Site Inspection
On April 6, 2009, Ronnie M. Davis, EPA's RPM for the Site, Stephen Johnson, DNREC's Project Manager for the Site, and Scott R~ Miller of Clean Sites Environmental Services, Inc., the representative for the PRPs, conducted a Site inspection as part of the five-year review process. The qbjective of the inspection was to assess the protectiveness of the remedy. The fence surrounding Landfill No.2 has been cut in several places, and it looks as if a tree fell on the fence at one location. Scott Miller will have the fence repaired by November 2009.
VII. TECHNICAL ASSESSMENT
Question A: Is the Remedy Functioning as Intended by the Decision Document? Yes.
The review of the site-related documents, risk assumptions, and the result Qf the Site inspection indicates that the remedy is functioning as intended by the ROD.
Question B: Are the Exposure Assumptions Data, Cleanup Levels, and Remedial Action Objectives (RAOs) Usedat the Time ofthe Remedy Selection Still Valid?
Yes.
Remedial Action Objectives
The goal of the remedial action was to reduce the potential for future contact with the waste or with Site contaminants, thereby reducing risks to within EPA guidelines. The cancer risks associated with no action at both landfills was at or above EPA's guideline of 1 x 10.4; after implementation of the selected remedy, cancer risks are below 1 x 10-6. The Hazard Index score was above 1.0 at both landfills; after implementation of the remedy, the Hazard Index score was reduced below 1.0. The security fence, cover material placed on the landfills, and closure of the leachate collection wells ~t Landfill No.2 have reduced the potential for contact with the landfill waste and
'leachate. Institutional controls have been implemented and all remedial action objectives have been met.
Because there are no users of ground water hydraulically downgradiel}t of Landfill No.1, monitoring of Landfill No.1 was conducted primarily for the protection of aquatic life in the Willis Branch. The trigger levels developed for each of the site related contaminant of concern for groundwater are as follows: styrene (2900 ug/L), and ethylbenzene (3,200 ug/L). The trigger levels for surface water for surface water monitoring are as follows: styrene (1,400 ug/L), ethylbenzene (1,600 ug/L), and.xylenes (900 ug/L).·
Because a few residential wells are located hydraulically downgradient of Landfill No 2, monitoring at Landfill No.2 has been conducted primarily for the protection of human health. The
10
trigger levels developed for each of the site-related contaminants of concern for ground water at Landfill No.2 are as follows: styrene (l00 ug/L), ethylbenzene (5 ug/L), 1,2,3-trichloropane (5 ug/L), phenolics (22,999 ug/L), and antimony (6 ug/L).
Changes in Standards and To Be Considered (TBCs)
There have been no changes in ARARs orTBCs that atTectthe protectiveness of the remedy. All ARARs were construction related.
Changes in Exposure Pathways, Toxicity, and Contaminant Characteristics
Because the State regulations under which the landfills were closed did not require deed restrictions on the property, EPA evaluated onsite risk under a hypothetical residential use
scenario. Risks to offsite residents resulting from exposure to contaminants released from landfill No.2 waste cells into the shallow groundwater following liner failure were also evaluated. The overall risks quantified in the risk assessment were primarily based upon exposure to the following compounds: benzene, cadmium, chloroform, dibutyi phthalate, manganese, phenol, cresol, ethylbenzene, and styrene. These assumptions are considered conservative and reasonable in
.evaluating and developing risk-based cleanup levels. No ~hanges to these assumptions; or the cleanup levels developed from them ,are warranted.
Question C: Has Any Other Information Come to Light That Could Call into Question the Protectiveness ofthe Remedy?
No.
Technical Assessment Summary
The review of the site-related documents, risk assumptions, and the results of the Site inspection indicates that the remedy is functioning as intended by the ROD. Currently, the land is not being used; however, during the Site inspection, one of the owners of Landfill No.2 expressed an interest in removing the fence from around the landfill and allowing deer to graze on the grass.
Groundwater monitoring was discontinued based on the recommendation to do so in the First Five-Year. During the preparation and completion of the Final Close Out Report in February 2009. EPA determined monitoring should resume at a minimum of every five years because waste has been left in place at the Site. A monitoring report was completed in April 2009 and EPA is preparing to delete the Site from the NPL. Therefore, it is recommended that an additional round of groundwater, surface water and sediment samples should be analyzed for the presence of volatile organic compounds, semiviolatile organic compounds, and metals.
II
VIII. ISSUES
Table 2 - Issues
Issue Currently Affects Protectiveness
(YIN) The chain link security fence has been cut in several places. Additionally, a tree has fallen on a section of the fence.
N
EPA is preparing to delete the Site from the NPL. Groundwater, surface water and sediments should be analyzed for the presence of volatile organic compounds, semiviolatile organic compounds, and metals.
N
"
Affects ·Future Protectiveness
(YIN) ,
N
N
IX. RECOMMENDATIONS AND FOLLOW-UP ACTION
Table 3 - Recommendations and Follow-Up Actions Issue Recommendations Party
Responsible Oversight Agency
Milestone Date
Affects Protectiveness? .
(YIN) Current Future
The chain link security fence has been cut in several
Repair the fence. PRP EPA November 2009
,
N N
places. Additionally, a tree has fallen on a
~
section of the fence. Groundwater, surface water and sediments should be analyzed for the presence of volatile organic compounds, semiviolatile organic compounds, and metals.
Monitor for volatile organic compounds; semivolatile organiC compounds and metals.
PRP EPA November 2009
N N
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X. PROTECTIVENESS STATEMENT
The remedy at the Site currently protects human health and the environment. The chain link security fences around the waste disposal areas of both landfills restrict access to the Site and reduce the potential for exposure to Site contaminants. The soil cover on the landfills prevents direct contact with the waste, minimizes migration of contaminants to the groundwater, and reduces the ,generation of leachate. There 'is no evidence of erosion or a breach of the soil cover on either landfill. The closure of the leachate collection wells at Landfill No.2 has reduced the potential for direct contact with leachate. Thus, there is no known evidence of current exposure to the waste'or Site contaminants and the remedy is considered protective in the short-term. In the long term, the remedy is protective because the deed restrictions (institutional controls) required by the ROD, which restrict the use of the land, have been implemented by the use of Environmental Easements. The institutional controls ensure long-term protectiveness by prohibiting any type'of activity that could disturb the landfill surfaces or the underlying waste at each landfill, or in any, way increase the risk of exposure to Site contaminants, including, but not limited to, any soildisturbing activities at the Site
XI. NEXT REVIEW
The next five-year review for the Coker's Sanitation Service Landfills Site is required in May 2014, five years from the date of this review. /
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