SDMS DoclD 2100122 

FINAL CLOSE OUT REPORT 

Coker's Sanitation Landfills Superfund Site 

Cheswold, Kent County, Delaware 

Prepared by: 

United States Environmental Protection Agency 

Region I11 

Philadelphia, Pennsylvania 

FER 19 2009 

William T. Wisniewski, Acting Regional Administrator Date 

U.S. EPA, Region I11 
Table of Contents 

Iv. 

v. 

VI. 

VII. 

VIII. 

IX. 

Introduction 1 

Summary of Site Conditions 1 

Background 1 

Remedial Investigation 1 Feasibility Study 2 

ROD Findings 2 

Remedial Construction Activities 3 

Community Relations Activities 5 

Site Redevelopment 6 

Demonstration of Cleanup Activity Quality Assurance and Quality Control 6 

Monitoring Results 6 

Summary of Operations and Maintenance 7 

Summary of Remediation Costs 7 

Protectiveness 7 

Five-Year Review 7 

Bibliography 8 

Figures 
FINAL CLOSE OUT REPORT 

Coker's Sanitation Service Landfills Superfund Site 

Cheswold, Kent County, Delaware 

I. Introduction 

This Final Close Out Report documents that the U.S. Environmental Protection Agency (EPA) 

completed all response actions for the Coker's Sanitation Service Landfills Superfund Site (Site) 

in accordance with Close Out Procedures for National Priorities List Sites (0s WER Directive 

9320.2-09A-P). 

11. Summary of Site Conditions 

Background 

The Site is located near Cheswold in Kent County, 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 part of larger, heavily 

wooded tracts of land (Figure 1). Properties adjacent to both landfills are primarily used for 

agricultural or light 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. 

Landfill #1 is located on the property of Mr. John Schmidt. Use of Landfill #1 began in 1969 

under a permit issued by the Delaware Water and Air Resources Commission. Subsequent 

permits (1 973-1976) were issued by the Delaware Department of Natural Resources and 

Environmental Control (DNREC). The landfill was closed in 1977 in accordance with Delaware 

Solid Waste Disposal Regulations of August 1974. During landfill operation, latex waste sludge 

was discharged into unlined trenches that were six to eight feet deep and twelve feet wide. 

Liquids were allowed to drain off as solids settled. Trenches were then backfilled with soil 

obtained locally. 

Landfill #2, located on property formerly owned by Mr. Joseph Kowinsky and currently owned 

by the estate of Genevieve M. Kowinsky, was operated from 1976 to 1980 under state permit. 

The permit required each six foot deep, twenty eight foot wide, one hundred and twenty five foot 

long trench to have a synthetic liner and a leachate collection and treatment, installation of 

ground water monitoring wells, and regularly scheduled site inspections, and periodic ground 

water and leachate monitoring. When the Site was closed in 1980, all trenches were capped with 
two feet of native soil. As waste settled and no longer generated collectable quantities of 

leachate, leachate collection was phased out in the early 1980's. 

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 leachate collection pipe. Bis(2-chloroethyl) 

ether was detected in Landfill No. 1 leachate seeps. EPA placed the Site on the National 

Priorities List (NPL) in July 1987. 

Remedial Investigation / Feasibility Study 

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 (RIIFS). On December 30, 1987, three PRPs signed an 

agreement with EPA in the form of an Administrative Order on Consent to conduct the RIIFS. 

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 levels. 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. 

The FS provided an in-depth analysis of several potentiaI remedial alternatives. The FS 

concluded that the no action alternative would not result in any reduction in overall risk posed by 

the Site. By fiat preventing contact with onsite contaminants and not preventing future 

residential use, this alternative would not be protective of human health and the environment. 

The FS provided a detailed analysis of the following alternatives: (1) no action; 

(2) Monitoring; (3) Limited Action; (4) Soil Cap; (5) Multi-Layer Cap (both landfills) and Subdrain (Landfill #1 only); (6) Volatile Organic Compound (VOC) Striping by Aeration ; and 

(7) Onsite Incineration. The FS also analyzed EPA's and DNREC's preferred alternative, 

alternative 3. 

ROD Findings 

EPA issued a Record of Decision (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. The site contains a large volume of 

material that would be difficult to handle and treat due to clay-like physical properties and the 

potential risk posed by substantial release of volatile organic compounds. EPA and the State 

determined that onsite containment of the waste was an appropriate remedial action. 

The selected remedy addresses the principal threats posed by the conditions at the Site by 

reducing the potential for human exposure to wastes remaining at the Site. 

The major components of the selected remedy are as follows: 

Deed restrictions will be placed on both landfill properties. 

The entire waste disposal areas of both landfills will be enclosed by a chain-link security 

fence with a locked gate to restrict the access of unauthorized persons and equipment 

onto the landfills. Appropriate warning signs will be placed along the fence. 

Cover material will be placed along the northern slope of Landfill No. 1 to eliminate 

exposure to leachate seeps. . 

' Areas of Landfill No. 2 which have subsided due to uneven settling of waste will be 

backfilled to grade and seeded. 

Leachate collection wells at Landfill No. 2 will be sealed with grout to reduce the potential 

for direct contact with leachate. 

Groundwater will be sampled semi-annually at both landfills. 

The landfills will be inspected semi-annually during groundwater sampling events. 

. 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 of no less than five 

years. 

Remedial Construction Activities 

The following is a summary of the activities that-were completed at the Site. 

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 between 

Kowinsky Farms, Inc, as Grantor, and DNREC, on 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 started construction activities in early July 1993. Remedial construction 

activities at Landfill No. 1 consisted of clearing the perimeter of vegetation so that the 

security fence could be installed. Leachate seeps were covered with wood chip mulch. 

Following installation of the security fence, cleared areas were seeded. Lastly, warning 

signs were posted around the landfill perimeter. 

At Landfill No.2, remedial construction activities were more extensive. First, the landfill 

was cleared of all vegetation. Trees within the landfill perimeter were cut and chipped for 

mulch. Each waste cell's leachate collection system was grout sealed. Settled waste cells 

were filled with clean fill and the entire landfill surface was re-graded. Top soil was 

added; the landfill was then graded and seeded. A security fence was installed around the 

landfill. Finally, warning signs were placed around the landfill perimeter. 

Three wells were sampled at Landfill No. 1 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. 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. 

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 repair, replacement of warning signs, and mowing the 

surface of Landfill No. 2. 

On September 9, 1993, EPA and DNREC conducted the final construction inspection. On 

September 29, 1993, EPA signed the Preliminary Site Close Out Report (PCOR), which 

documented that the PRPs had completed construction activities at the Site. The PCOR identified 

a series of tasks remaining through the Final Close Out Report. Each of these tasks, along with its 

resolution, is summarized in the following table: 
Task Resolution 

(1) Pre-certifcation inspection 

(2) Remedial Action Report 

Submission 

I certification inspection. 

I 

I 

A pre-final construction inspection was conducted by 

the State, EPA, and the Settlors on November 4, 1993. 

EPA approved the Remedial Action Report on July 15, 

1994. 

(3) Site Grade inspection 

(4) Established growth 

(5) Erosion control removal 

The final construction inspection was performed on 

November 4,1993. 

Site Inspection was performed on June 2, 1994 by 

Clean Site. 

This was completed before the November 4, 1993 Pre- 

(6) Deed Restriction 

Community Relations Activities 

The Environmental Protection Easement and 

Declaration of Restrictive Covenants for Landfill #1 

was signed on February 24,2005 and was singed for 

Landfill #2 on September 24,2008. 

(7) Final Close Out Report 

(8) Work Report (Operation & 

Maintenance 

Before the start of construction activities, representatives from Clean Sites visited residents 

whose homes were adjacent to the landfills on both sides of CR 152. Residents who were at 

home at the time of the visit were informed of the start date, the nature and duration of the 

construction activities. Clean Sites representatives answered questions that the residents asked 

about the construction activities. Handbills, advising the residents of the construction activities, 

were given to residents in person or were placed in their mailboxes. EPA issued a fact sheet in 

July 1993 at about midway through the construction activities. The fact sheet presented a 

description of the site remedial action and project status. 

The Final Close Out Report was completed on February 

19,2009 

The work report was completed on December 18,2008. 

EPA notified local officials about upcoming Five-Year Reviews. Notices were placed in the 

Delaware State News by EPA to inform the public that the Five-Year Reviews were being 

conducted and when the findings would be available. 
In June 2006, EPA and DNREC discussed the status of the Site at a Cheswold Town Meeting . The town was considering annexing land, which included Landfill #2. 

Site Redevelopment 

There are currently no redevelopment plans, but any future plans would have to take into account 

the permanent aspects of the remedy. The landfill waste remains in place and must not be 

disturbed by construction activities. No wells, except monitoring wells, may be drilled in the 

landfill area. EPA and DNREC will review the safety of any proposed redevelopment. 

111. Demonstration of Cleanup Activity Quality Assurance and Quality Control 

Activities conducted at the site were consistent with the ROD, all work plans, and the 

performance standards attached to the Consent Decree as Appendix D. The remedial design (RD) 

plans and specifications included a Quality Assurance Project Plan (CQPjPA). Only EPA 

analytical methods were used for all validation of Contract Laboratory Program (CLP) methods 

and procedures. All procedures and protocols identified in the QAPjP were followed. EPA7s 

Central Regional Laboratory in Annapolis, Maryland reviewed the QAPjP and the Sampling and 

Analysis Plan (SAP) and recommended approval. All sampling was conducted in accordance 

with the CLP Statements of Work and accepted methods. 

The U. S. Army Corps of Engineers (Corps of Engineers) performed technical oversight for EPA. 

The Corps of Engineers were on-site approximately 50% of the time. The Corps of Engineers 

presence coupled with State and EPA oversight during sampling and construction activities 

ensured that the remedial action was conducted according to the approved design and 

specifications. 

The Quality Assurance and Quality Control (QAIQC) program utilized throughout the Remedial 

Action was sufficiently rigorous and was adequately complied with by the Settlors. The State and 

EPA determined that the analytical results reported were accurate to the degree needed to assure 

satisfactory execution of the Remedial Action Plan consistent with the ROD, Consent Decree, and 

the RD plan and specifications. 

IV. Monitoring Results 

The EPA approved the Sampling and Analysis Plan (Part IV of the RD Submittal) requiring 

periodic sampling of groundwater, surface water and sediments. The initial semi-annual samples 

were collected at the start of the remedial action (RA) activities. Sampling results were presented 

to EPA on August 5, 1993 in a monitoring report. Based on the sampling results, none of the 

established trigger levels were exceeded. Six years of post RA monitoring occurred at the Site, 

before EPA decided that monitoring will be required once every five years based on the fact that 

no constituents were detected at concentrations exceeding the established trigger levels. 
V. Summary of Operations and Maintenance 

The landfills were inspected semi-annually to identi@ any maintenance activities that needed to be 

conducted to ensure continued performance of the remedial action. Inspection frequency was 

quarterly for the first year to provide for seep cover inspection and maintenance. The EPA 

approved Operations and Maintenance (O&M) Plan presented the requirements for the Site 

inspections, and included a checklist that was used to document inspection observations and 

results. The inspection and maintenance period began following EPAYs certification that the 

remedial action activities were completed. O&M activities that will continue at the Site will be 

mowing the grass and semi-annual inspections. 

VI. Summary of Remediation Costs 

The ROD cost estimate for total remedy cost (Capital + O&M) was $1,240,000. The remedial 

action was PRP lead, and the Settlors did not provide EPA with any further cost information. 

VII. Protectiveness 

This site meets all the site completion requirements as specified in OSWER Directive 9320.2-09- 

A-P, Close Out Procedures for National Priorities List Sites. All cleanup actions specified in the 

ROD have been implemented. All ROD cleanup standards have been achieved. The site no 

longer poses a threat to human health or the environment. The only remaining activities to be 

performed at the Site are O&M and five-year reviews. A bibliography of all reports relevant to 

the cleanup of this Site under the Superfund program is attached. 

VIII. Five-Year Review 

EPA has already conducted two statutory Five-Year Reviews for this Site. Since the remedies 

selected for the Coker's Landfill Site allow hazardous substances, pollutants, or contaminants to 

remain on-site above levels that allow for unlimited use and unrestricted exposure, statutory FiveYear Reviews are required. These reviews were conducted pursuant to CERCLA 121 (c) and as 

provided in the current guidance on Five-Year Reviews: OSWER No. 9355.7-03B-P, 

"Comprehensive Five-Year Review Guidance." 

The most recent five-year review was completed on May 25,2004. One issue affecting the 

protectiveness of the remedy for the Site was identified during the five-year review process. That 

issue was the need to implement the deed restrictions (institutional controls), which are elements of 

the selected reedy set forth in the ROD. Deed restrictions have been placed on both landfills in the 

form of Environmental Protection Easement and Declaration of Restrictive Covenants. 

The next Five-Year Review will be completed by May 25,2009. 
IX. Bibliography 

Clean Sites, Inc. (1993). " Operations and Maintenance Plan Coker's Landfills, Cheswold, 

Delaware'." 

Nabisco Brands, Inc.; Reichold Chemicals, Inc. ; Rapid American Corportion; and EPA (December 

30, 1987) "Administrative Order on Consent, Docket No. 111-16-DC." 

U.S. Environmental Protection Agency (1990). "Superfund Record of Decision: Coker's Sanitation 

Service Landfills." 

U.S. Environmental Protection Agency (1993). "Superfund Preliminary Close Out Report. Coker's 

Sanitation Service Landfills, Cheswold, Kent County Delaware." 

Clean Sites, Inc. (December 3, 1993). "Remedial Action Certification Report The Coker Sanitation 

Services Site, Cheswold, Delaware." 

U.S. Environmental Protection Agency (1999). "Five Year Review Report. Coker's Sanitation 

Service Landfills, Cheswold, Kent County Delaware." 

U.S. Environmental Protection Agency (2004). "Five Year Review Report (Second Report). 

Coker's Sanitation Service Landfills, Cheswold, Kent County Delaware." 
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