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 RelationsActivities 5 

### Site Redevelopment 6 Demonstration of Cleanup Activity Quality Assurance and Quality Control 6 MonitoringResults 6 Summary of Operations and Maintenance 

### 7 Summary of Remediation Costs 7 

### Protectiveness 7 

### Five-Year Review 

### 7 Bibliography 8 FiguresFINAL 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 accordancewith Close OutProcedures 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 adjacentto both landfills are primarily used for agricultural or light residential development. Landfill No. 1isbordered 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 (1973-1976) 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 ofAugust 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 allowedto 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 GenevieveM. Kowinsky,was operated from 1976to 1980under 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 leachatemonitoring. When the Site was closed in 1980, all trenches were capped withtwo 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 collectionpipe on Landfill No. 2. Ethylbenzene was detected in the same well and leachate collection pipe. Bis(2-chloroethyl) ether was detected in Landfill No. 1leachate seeps. EPA placed the Site on the National PrioritiesList (NPL) in July 1987. Remedial Investigation / Feasibility Study In April 1986, EPA issued lettersto severalPotentially Responsible Parties (PRPs) notifying them of their potential liability for Siteresponse actions and invitingthem to conduct the Remedial Investigation/FeasibilityStudy (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 separateorder, to remove drums containingvarying 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 landfillscontained the highest number of contaminants and highest levels of contamination,primarily styrene, ethylbenzene, and phenolic compounds. Leachate from Landfill No. 2 (taken from leachate collectiontrenches 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 compoundsbut 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 severalpotentiaI remedial alternatives. The FS concluded that the no action alternativewould not result in any reduction in overall risk posed by the Site. By fiat preventing contactwith onsite contaminantsand not preventing future residential use, this alternativewould not be protective ofhuman 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) Stripingby 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 restrictionsto 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 norhighly mobile, and can be reliably controlled in place. The site contains a large volume of material that would be difficultto handle and treat due to clay-like physical properties and the potential risk posed by substantialrelease of volatile organic compounds. EPA and the State determined that onsite containment of the waste was an appropriate remedial action. The selectedremedy addresses the principal threatsposed by the conditions at the Siteby reducing the potential for human exposure to wastes remaining at the Site. The major components of the selected remedy are as follows: Deed restrictionswill be placed on both landfill properties. The entire waste disposal areas ofboth landfillswill be enclosed by a chain-link security fence with a locked gate to restrict the access ofunauthorized persons and equipment onto the landfills.Appropriate warning signswill be placed along the fence. Cover material will be placed along the northern slope of Landfill No. 1to eliminate exposureto leachate seeps.

.

' Areas of Landfill No. 

### 2 which have subsided due to uneven settling ofwaste 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 landfillswill be inspected semi-annually during groundwater sampling events.



# . Surfacewater 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-werecompleted at the Site. An Environmental Protection Easement and Declaration of Restrictive Covenantsbetween 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 18,2005to implement the institutional controls for Landfill No. 1.

### An Environmental ProtectionEasement and Declaration of RestrictiveCovenants between Kowinsky Farms, Inc, as Grantor, and DNREC, on behalf of the State of Delaware, as Grantee, relating to LandfillNo.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 controlsfor Landfill No.2. The PRPs started construction activities in early July 1993. Remedial construction activities at Landfill No. 1consisted 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 activitieswere 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. Settledwaste cells were filled with clean fill and the entire landfill surfacewas 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 concentrationsthree 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 activitieshave generallyconsisted of minor fencerepair, replacement of warning signs, and mowing the surface of Landfill No. 2. On September9, 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 constructioninspection was conducted by

the State,EPA, and the SettlorsonNovember 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 constructioninspection was performed on November 4,1993. Site Inspection was performed on June 2, 1994by Clean Site. This was completed before the November 

### 4, 1993Pre- 

### (6) Deed Restriction

Community Relations Activities The Environmental ProtectionEasement and Declaration of RestrictiveCovenants for Landfill #1 was signed on February 24,2005 and was singed for Landfill #2 on September24,2008. (7)Final Close Out Report (8)Work Report (Operation & Maintenance

Before the start of construction activities,representatives from Clean Sitesvisited residents whose homes were adjacent to the landfills on both sides of CR 152. Residentswho were at home at the time of the visit were informed of the start date, the nature and duration of the construction activities. Clean Sitesrepresentatives answered questionsthat 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 1993at about midway through the construction activities.The fact sheet presented a description of the siteremedial 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 StateNews by EPA to inform the public that the Five-Year Reviews were being conducted and when the findingswould 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 currentlyno 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 samplingwas 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 approximately50% ofthe time. The Corps of Engineers presence coupled with State and EPA oversight during sampling and construction activities ensured that the remedial action was conducted accordingto the approved design and specifications. The Quality Assurance and Quality Control (QAIQC)program utilized throughout the Remedial Action was sufficientlyrigorous 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 ofthe 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, surfacewater and sediments. The initial semi-annual samples were collected at the start ofthe remedial action (RA) activities. Sampling results were presented to EPA on August 5, 1993in a monitoringreport. Based on the sampling results, none of the establishedtrigger levels were exceeded. Sixyears 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 landfillswere inspected semi-annually to identi@any maintenance activitiesthat needed to be conducted to ensure continued performance of the remedial action. Inspection frequency was quarterlyfor the firstyear to provide for seep cover inspection and maintenance. The EPA approved Operations and Maintenance (O&M) Plan presented the requirementsfor the Site inspections,and included a checklistthat was used to document inspection observationsand results. The inspection and maintenance period began followingEPAYs certification that the remedial action activitieswere completed. O&M activitiesthat 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 Settlorsdid not provide EPA with any further cost information. VII. Protectiveness This site meets all the site completionrequirements as specified in OSWER Directive 9320.2-09- A-P, Close OutProcedures for National PrioritiesList Sites. All cleanup actions specified in the ROD have been implemented. All ROD cleanup standardshave been achieved. The site no longerposes 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 Superfundprogram 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 allowhazardous substances, pollutants, or contaminantsto 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-yearreview was completed on May 25,2004. One issue affecting the protectiveness of the remedy for the Site was identified during the five-year reviewprocess. That issue was the need to implement the deed restrictions (institutional controls),which are elements of the selectedreedy set forth in the ROD. Deed restrictionshave been placed on both landfills in the form ofEnvironmental ProtectionEasement 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 ProtectionAgency (1990). "Superfund Record of Decision: Coker's Sanitation Service Landfills." U.S. Environmental ProtectionAgency (1993). "Superfund Preliminary Close Out Report. Coker's SanitationService Landfills, Cheswold, Kent County Delaware." Clean Sites,Inc. (December 3, 1993). "Remedial Action CertificationReport The Coker Sanitation Services Site, Cheswold, Delaware." U.S. Environmental ProtectionAgency (1999). "Five Year Review Report. Coker's Sanitation Service Landfills, Cheswold, Kent County Delaware." U.S. Environmental ProtectionAgency (2004). "Five Year Review Report (Second Report). Coker's Sanitation ServiceLandfills, Cheswold, Kent County Delaware."

# Figures