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National Oil and Hazardous Substances Pollution Contingency Plan; National Priorities List

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AGENCY:

Environmental Protection Agency.

ACTION:

Direct final notice of deletion of the Sussex County Landfill No. 5 Superfund Site from the National Priorities List.

SUMMARY:

The Environmental Protection Agency (EPA) Region III is publishing a direct final notice of deletion of the Sussex County Landfill No. 5, Superfund Site (Site), located in Laurel, Delaware from the National Priorities List (NPL).

The NPL, promulgated pursuant to Section 105 of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980, as amended, is Appendix B of 40 CFR Part 300, which is the National Oil and Hazardous Substances Pollution Contingency Plan (NCP). This direct final notice of deletion is being published by EPA with the concurrence of the State of Delaware, through the Department of Natural Resources and Environmental Control, because EPA has determined that all appropriate response actions under CERCLA have been completed and, therefore, further remedial action pursuant to CERCLA is not appropriate.

DATES:

This direct final deletion will be effective September 28, 2001 unless EPA receives adverse comments by August 29, 2001. If adverse comments are received, EPA will publish a timely withdrawal of the direct final deletion in the Federal Register informing the public that the deletion will not take effect.

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ADDRESSES:

Comments may be mailed to: Richard Kuhn, Community Involvement Coordinator (3HS43), E-mail: kuhn.richard@epa.gov, U.S. EPA Region III, 1650 Arch Street, Philadelphia, PA 19103-2029, (215) 814-3063 or 1-800-352-1973, ext. 4-3063.

Information Repositories: Comprehensive information about the Site is available for viewing and copying at the Site information repositories located at: U.S. EPA Region III, Regional Center for Environmental Information (RCEI), 1650 Arch Street (2nd Floor), Philadelphia, PA 19103-2029, (215) 814-5254, Monday through Friday 8 a.m. to 5 p.m.; Laurel Public Library, 6 East Fourth Street, Laurel, DE 19956, (302) 875-3184, Monday through Thursday 10 a.m. to 8 p.m., Friday 10 a.m. to 5 p.m., Saturday 10 a.m. to 2 p.m.; and the Delaware Department of Natural Resources and Environmental Control, Division of Air and Waste Management, 391 Lukens Drive, Riveredge Industrial Park, New Castle, DE 19720, (302) 395-2600, Monday through Friday 8:00 a.m. to 4:00 p.m.

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FOR FURTHER INFORMATION CONTACT:

Humberto J. Monsalvo, Jr., Remedial Project Manager (RPM) (3HS23), E-mail: monsalvo.humberto@epa.gov, U.S. EPA Region III, 1650 Arch Street, Philadelphia, PA 19103-2029, (215) 814-2163 or 1-800-352-1973 ext. 4-2163, FAX (215) 814-3002.

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SUPPLEMENTARY INFORMATION:

Table of Contents

I. Introduction

II. NPL Deletion Criteria

III. Deletion Procedures

IV. Basis for Site Deletion

V. Deletion Action

I. Introduction

EPA Region III is publishing this direct final notice of deletion of the Sussex County Landfill No. 5 Superfund Site from the NPL.

The EPA identifies sites that appear to present a significant risk to public health or the environment and maintains the NPL as the list of those sites. As described in 40 CFR 300.425(e)(3) of the NCP, sites deleted from the NPL remain eligible for remedial actions if conditions at a deleted site warrant such action.

EPA considers this action to be noncontroversial and routine; as such, EPA is taking it without prior publication of a notice of intent to delete. This action will be effective September 28, 2001 unless EPA receives adverse comments by August 29, 2001 on this notice. If adverse comments are received within the 30-day public comment period on this action to delete, EPA will publish a timely withdrawal of this direct final notice of deletion before the effective date of the deletion and the deletion will not take effect. EPA will, as appropriate, prepare a response to comments and continue with the deletion process on the basis of the notice of intent to delete and the comments already received. There will not be any additional opportunity to comment.

Section II of this document explains the criteria for deleting sites from the NPL. Section III discusses procedures that EPA is using for this action. Section IV discusses the Sussex County Landfill No. 5 Superfund Site and demonstrates how it meets the deletion criteria. Section V discusses EPA's action to delete the Site from the NPL unless adverse comments are received during the public comment period.

II. NPL Deletion Criteria

Section 300.425(e) of the NCP provides that releases may be deleted from the NPL where no further response is appropriate. In making a determination to delete a release from the NPL, EPA shall consider, in consultation with the State, whether any of the following criteria have been met:

i. Responsible parties or other persons have implemented all appropriate response actions required;

ii. All appropriate Fund-financed (Hazardous Substance Superfund Response Trust Fund) response under CERCLA has been implemented, and no further response action by responsible parties is appropriate; or

iii. The remedial investigation has shown that the release poses no significant threat to public health or the environment and, therefore, the taking of remedial measures is not appropriate.

Even if a site is deleted from the NPL, where hazardous substances, pollutants, or contaminants remain at the deleted site above levels that allow for unlimited use and unrestricted exposure, CERCLA Section 121(c), 42 U.S.C. 9621(c) requires that a subsequent review of the site be conducted at least every five years after the initiation of the remedial action at the deleted site to ensure that the action remains protective of public health and the environment. If new information becomes available which indicates a need for further action, EPA may initiate remedial actions. Whenever there is a significant release from a site deleted from the NPL, the deleted site may be restored to the NPL without application of the hazard ranking system.

III. Deletion Procedures

The following procedures apply to deletion of the Site:

(1) The EPA consulted with Delaware on the deletion of the Site from the NPL prior to developing this direct final notice of deletion.

(2) Delaware concurred with deletion of the Site from the NPL

(3) Concurrently with the publication of this direct final notice of deletion, a notice of the availability of the parallel notice of intent to delete published today in the “Proposed Rules” section of the Federal Register is being published in a major local newspaper of general circulation at or near the Site and is being distributed to appropriate federal, state, and local government officials and other interested parties; the newspaper notice announces the 30-day public comment period concerning the notice of intent to delete the Site from the NPL.

(4) The EPA placed copies of documents supporting the deletion in the Site information repositories identified above.

(5) If adverse comments are received within the 30-day public comment period on this notice or the companion notice of intent to delete also published in today's Federal Register, EPA will publish a timely notice of withdrawal of this direct final notice of deletion before its effective date and will prepare a response to comments and continue with the deletion process on the basis of the notice of intent to delete and the comments already received.

Deletion of a site from the NPL does not itself create, alter, or revoke any individual's rights or obligations. Deletion of a site from the NPL does not in any way alter EPA's right to take enforcement actions, as appropriate. The NPL is designed primarily for informational purposes and to assist EPA management. Section 300.425(e)(3) of the NCP states that the deletion of a site from the NPL does not preclude eligibility for future response actions, should future conditions warrant such actions.

IV. Basis for Site Deletion

The following information provides EPA's rationale for deleting the Site from the NPL:

A. Site Location

The Site, also known as the Laurel Landfill, is a 38-acre landfill located off Route 494 and approximately 1 mile west of the Laurel Airport in Laurel, Delaware. The surrounding area is agricultural and residential. Start Printed Page 39282

B. Site History

The landfill was in operation between May 1970 and August 1979 and during that time accepted municipal and industrial waste. Waste was disposed in trenches which were excavated into the native soil. Waste placed in the landfill was covered by approximately two feet of soil obtained from soil stockpiles generated during the excavation of the trenches. After the landfill closed in 1979, a transfer station for municipal waste was operated on the northwest corner of the property under permit from the Delaware Department of Natural Resources and Environmental Control (DNREC) until 1993. During the 1980s, several investigations of the landfill were conducted by DNREC and Sussex County. As a result of these investigations, DNREC determined that ground water in the vicinity of the landfill had been impacted by contaminants coming from the landfill. On August 8, 1988, DNREC and Sussex County signed a Memorandum of Understanding to support the development and implementation of the Ground Water Management Zones (GMZs). GMZs were subsequently developed for the landfill and approved by DNREC. Three GMZs were established in the area surrounding the landfill; one of these restricted the installation of new ground water pumping wells (No Well Zone) and two of these restricted pumping rates of any new and existing wells (GMZ A-Wells less than 10 g.p.m. and GMZ B-Wells less than 100 g.p.m.).

In 1986, EPA completed a Site Inspection which indicated that ground water in the area of the landfill had become contaminated with volatile organic compounds (VOCs) and metals coming from the landfill. The Site was proposed for the National Priorities List (NPL) in June 1988 and was added to the list on October 4, 1989. On April 4, 1991 EPA and Sussex County entered into an Administrative Order on Consent which required Sussex County to conduct a Remedial Investigation (RI) and Feasibility Study (FS) for the Site.

Remedial Investigation and Feasibility Study (RI/FS)

Ground water samples obtained from onsite and offsite monitoring wells and two irrigation wells during the RI indicated ground water was mainly contaminated with low levels [in the low micrograms per liter (ug/L) range] of VOCs. Benzene and vinyl chloride were the only VOCs which were detected at concentrations above the Safe Drinking Water Act's Maximum Contaminant Levels (MCLs). VOC ground water contamination extended 1,000 feet down gradient of the northwest corner of the landfill.

The analytical data generated from the RI showed no apparent adverse impacts on sediment, soil, and surface water quality at the landfill.

During the RI, one offsite residential well was found to be contaminated with vinyl chloride just above the Safe Drinking Water Act MCL. As a result, Sussex County provided this resident with bottled water and later in February 1993 Sussex County installed a carbon filter water treatment system on this well to remove VOCs and an ultraviolet light to reduce bacteria levels.

In October 1993, Sussex County completed the RI which included EPA-prepared Baseline Human Health Risk Assessment and Ecological Risk Assessment. The Risk Assessment indicated that very low levels of contaminants of concern existed in the ground water which translated into correspondingly low risk levels at the Site. Based on the results of the RI and the Risk Assessments, EPA determined that a feasibility study was not necessary to evaluate remedial alternatives.

Record of Decision Findings

Based on the results of the RI and Risk Assessment and in light of the activities being taken by DNREC and Sussex County under a Notice of Conciliation (NOC) signed by both parties in August 1994, EPA did not require any clean-up action to be taken at the Site under CERCLA. On December 29, 1994, EPA issued a No Action Record of Decision (ROD) which stated Five-Year Reviews would be conducted in order to determine if conditions at the Site remain protective of human health and the environment.

According to the NOC, Sussex County was to perform the following activities:

  • Provide Public Water Supply to Residents Down Gradient of the Landfill
  • Establish a Ground Water Monitoring Program
  • Maintenance of the Vegetated Soil Cover
  • Restrict Well Installation and/or Operation in the GMZs
  • Institutional Controls

Characterization of Risk

The baseline risk assessment performed by EPA in 1994 determined through screening and evaluation of the Site media data that the only route of exposure of toxicological significance was through ground water. EPA assessed carcinogenic and non-carcinogenic risks from current and potential future exposure to contaminated ground water in residential well RW-02. In addition, EPA assessed carcinogenic and non-carcinogenic risks due to potential migration of the organic contaminant plume offsite. EPA used data from monitoring wells LD-1, LS-7R, and LS-16 to represent the center of the organic contaminant plume that was considered to be the source of exposure to receptors if the contaminant plume were to migrate to some offsite point where this water may be used for future residential purposes.

The risk assessment concluded that very low levels of contaminants of concern existed in the ground water corresponding to low risk levels at the Site. The increased carcinogenic risk for the residential exposure pathway was just slightly above the generally acceptable risk level of 1.0 E-04. The noncarcinogenic risk, or Hazard Index, calculated for the residential exposure pathway was 1.23 and the hazard was mainly attributable to inhalation of volatile organic compounds during showering. This Hazard Index value was marginally above EPA's generally acceptable level of 1.0. For the exposure pathway calculated using monitoring well data, the Hazard Index was 2.68 indicating that noncarcinogenic effects may be expected to occur if exposure to this ground water were to occur in the future.

In 1999, EPA conducted a five-year review for the Site. During the preparation of the Five-Year Review Report, EPA reviewed the ground water data collected since the ROD date to determine if the risks associated with the Site had increased, or if assumptions or input values used in the baseline risk assessments had changed significantly enough to require a new risk assessment for the Site. The review of the ground water sampling data for the contaminants of concern revealed that overall the concentration levels had not increased since the baseline risk assessment was performed. The assumptions and input values for the Site contaminants of concern used in the baseline risk assessment had not changed since the issuance of the ROD with the exception of the oral exposure reference dose (RfD) for 1,4-dichlorobenzene, a volatile organic compound. The oral RfD had been revised to a more stringent value than the RfD used in the baseline risk assessment. EPA conducted a qualitative assessment and determined that the Hazard Index calculated for the Site would not significantly change due to the revised RfD for 1,4-dichlorobenzene. EPA also conducted an Ecological Risk Assessment to Start Printed Page 39283evaluate any actual or potential ecological risk as a result of exposure to Site-related contaminants of concern. This assessment concluded that a negligible potential exists for negative impact to habitats onsite and in the surrounding area. The human health and ecological risk posed by the Site is negligible.

Response Actions

On December 29, 1994 EPA issued a No Action Record of Decision; therefore, no CERCLA remedial action was conducted at the site. However, Sussex County performed the following work in accordance with the requirements of the Notice of Conciliation entered into with DNREC:

(1) Provide Public Water Supply to Residents Down Gradient of the Landfill. A public water supply well, approximately 300 feet deep, was installed by Sussex County west of the landfill. The construction of the public water supply pipeline was completed in 1995 and residential connections to the system also began. As of December 1995, nineteen residences were connected to the public water supply system and by March 1996, one additional connection was completed. Sussex County had provided a carbon treatment unit for one residential well (RW-02) in which vinyl chloride had been detected at concentrations above the MCL. The treatment system was removed and this residential well was renamed monitoring well LS-20 after the residence was connected to the public water supply system. The public water supply system is currently owned and operated by Tidewater Utilities Company. The public supply well is tested by Sussex County approximately once annually. The Delaware Department of Public Health currently oversees the Tidewater Utilities Company monitoring program for the public supply well.

(2) Establish a Ground Water Monitoring Program. A ground water monitoring program was established by Sussex County and approved by EPA and DNREC which included quarterly sampling for one year (November 1994-October 1995) and then semi-annual sampling thereafter. The monitoring program currently consists of monitoring wells within, down gradient and west of the landfill; residential wells down gradient of the landfill which have not connected to the public water supply; an irrigation well; an up gradient residential well and an up gradient monitoring well. As of 2000, the wells are sampled annually.

The samples are analyzed for volatile organic compounds and ammonia as nitrogen (N), chloride, soluble iron, soluble manganese, nitrate-nitrite measured as nitrogen (mg-N/L), total dissolved solids, pH, and specific conductance.

(3) Maintenance of the Vegetated Soil Cover. The NOC required Sussex County to maintain the integrity and effectiveness of the vegetated soil cover to correct any effects of settling, subsidence, and erosion and to prevent precipitation from eroding or otherwise damaging the cover which prevents direct contact with the waste material. In July 1995, DNREC approved the Site Care Work Plan submitted by Sussex County. The work consisted of clearing and grubbing areas to be backfilled, backfilling and compacting areas to grade in order to alleviate standing water and to produce an even fill surface throughout areas of the landfill designated by DNREC; constructing four swales in order to encourage drainage of water from the landfill surface; and grading and seeding the backfilled areas. Sussex County did not disturb any existing vegetation or trees in the areas of the landfill that DNREC did not require backfilling and grading. By March 1998, Sussex County had completed all Site care work had been completed by Sussex County. Sussex County inspects the landfill cover at least once a year to determine if wastes are exposed, or excessive erosion or surface water ponding is occurring.

(4) Restrict Well Installation and/or Operation in the GMZs. The NOC required Sussex County to continue implementing the GMZs as described in the August 1988 Memorandum of Understanding between the DNREC and Sussex County. Installation of drinking water wells are carefully controlled or restricted in the GMZs. There are three areas within the GMZ:

  • No well installation area
  • GMZ-A: limited to wells with a pumping rate of less than 10 gallons per minute (g.p.m.)
  • GMZ-B: limited to wells with a pumping rate of less than 100 g.p.m.

To date, the GMZs have been maintained and controlled through the oversight efforts of DNREC and Sussex County.

(5) Institutional Controls. The NOC required Sussex County to record with the recorder of deeds a notation that will in perpetuity notify any potential purchaser that the property was used as a solid waste disposal Site and that land use restrictions under DNREC Regulations Governing Solid Waste apply. On March 26, 1996, Sussex County Council recorded a “Declaration of Restriction” with the Sussex County Recorder of Deeds addressing the requirements of the NOC. In addition, a statement restricting the landfill property from commercial or residential use and restricting any person from inhabiting or occupying the land at any future time was included in this “Declaration of Restriction.”

Cleanup Standards

EPA issued a No Action Record of Decision in 1994; therefore, no cleanup standards were established because the low contaminant and human health and environmental risk levels associated with the Site did not warrant cleanup activities. Sussex County and DNREC operating under the requirements of the Notice of Conciliation which both parties signed in 1994 continue to maintain the Ground Water Management Zones and the soil surface landfill cover; restrict commercial or residential use of the landfill, and monitor ground water in and surrounding the landfill to reduce the potential for exposure of human and environmental receptors to landfill wastes.

Five-Year Review

In 1999, EPA conducted the first CERCLA Five-Year Review of the Site to determine if the chosen No Action remedy was still protective of human health and the environment. In order to evaluate the protectiveness of the remedy, EPA performed a Site visit, reviewed data, conducted interviews, and evaluated the work performed at the landfill since the Record of Decision was signed in 1994. Ground water data from the Site reviewed during this Five-Year review period indicated that there are no human exposures to VOCs in ground water at or surrounding the landfill. The data revealed that the nitrate-nitrite level in the ground water is elevated above the Safe Drinking Water Act's Maximum Contaminant Level (MCL). The presence of nitrate or nitrite in drinking water sources is mainly a concern for infants under six months due to the possibility of “Blue Baby Syndrome” in which an infant experiences shortness of breath and therefore may look blue. Elevated levels of nitrate-nitrite above the 10 ug/L MCL were detected in ground water samples from monitoring and private wells, both up gradient and down gradient of the landfill indicating that the source of this nitrate-nitrite is not likely the landfill. EPA discussed the elevated nitrate-nitrite levels with DNREC and the Delaware Department of Public Health and learned that it is typical to find nitrate-nitrite levels in the 10-15 ug/L range in ambient ground water in Sussex County, Delaware. Since the Start Printed Page 39284nitrate-nitrite levels in ground water drinking wells in the area of the landfill are within the ambient (10-15 ug/L) range typically found in Sussex County and the nitrate-nitrite levels were elevated in monitoring wells located up gradient of the landfill, the landfill did not appear to be the source of nitrate-nitrite in ground water. Private residential wells serving less than 25 people are not regulated by the Safe Drinking Water Act; therefore, EPA, DNREC and Sussex County decided to send public information fact sheets to the residents to inform them of the potential adverse health effects due to elevated levels of nitrate-nitrite in drinking water and precautions the public can take to reduce exposure to nitrate-nitrite. In summary, EPA concluded that conditions at the Site had not worsened and no additional risks are presented to human health and the environment at the Site since the signing of the No Action ROD in 1994; therefore, EPA concluded that the No Action remedy was still protective of human health and the environment.

In the 1999 Five-Year Review Report, EPA recommended the following activities be performed by Sussex County so that it can continue to monitor the conditions at the landfill and surrounding area in order to ensure continued protectiveness of human health and the environment. These recommended actions are the following: continue the ground water monitoring program, modifying it as necessary, and maintain the Ground Water Management Zones; continue maintenance of the vegetative soil landfill cover; and notify the residents nearby the landfill who have not been connected to the public water supply system of the elevated levels of nitrate-nitrite in the ground water and that the source of this nitrate-nitrite does not appear to be the landfill.

Sussex County in cooperation with DNREC followed up on these recommendations by issuing public information Fact Sheets to the nearby residents who still use ground water from private wells. The facts sheets informed the residents of the presence of elevated levels of nitrates-nitrites in the water and discussed precautions they could follow to reduce the impact of these nitrate-nitrites on their health. In addition, Sussex County is, with oversight by DNREC, continuing to maintain the integrity and effectiveness of the landfill vegetative soil cover as required in the NOC, and maintain the Ground Water Management Zones. In addition, Sussex County has modified the Ground Water Monitoring Program in accordance with the NOC and MOU and continues to conduct the Ground Water Monitoring Program at the Site according to DNREC's requirements and as outlined in a revised Memorandum of Understanding (MOU-2) signed between DNREC and Sussex County on March 14, 2000.

Since waste is being left in place at the landfill, EPA will continue to conduct Five-Year Reviews at the Site. The date for the next EPA five-year review is December 2004.

Community Involvement

Public participation activities have been satisfied as required in CERCLA Section 113(k), 42 U.S.C. 9613(k), and CERCLA Section 117, 42 U.S.C. 9617. Documents in the deletion docket which EPA relied on for recommendation of the deletion from the NPL are available to the public in the information repositories.

V. Deletion Action

The EPA, with concurrence of the State of Delaware, has determined that all appropriate responses under CERCLA have been completed, and that no further response actions, under CERCLA, other than Five-Year Reviews, are necessary. Therefore, EPA is deleting the Site from the NPL.

EPA considers this action to be noncontroversial and routine; as such, EPA is taking it without prior publication of a notice of intent to delete. This action will be effective September 28, 2001 unless EPA receives adverse comments by August 29, 2001 on a parallel notice of intent to delete published in the Proposed Rule section of today's Federal Register. If adverse comments are received within the 30-day public comment period on the proposal, EPA will publish a timely withdrawal of this direct final notice of deletion before the effective date of the deletion, and it will not take effect, EPA will then prepare a response to comments and continue with the deletion process on the basis of the notice of intent to delete and the comments already received. There will not be any additional opportunity to comment.

Start List of Subjects

List of Subjects in 40 CFR Part 300

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Dated: July 23, 2001.

Thomas C. Voltaggio,

Acting Regional Administrator, EPA Region III.

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For the reasons set out in this document,

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PART 300—[AMENDED]

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1. The authority citation for Part 300 continues to read as follows:

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Authority: 33 U.S.C. 1321(c)(2); 42 U.S.C. 9601-9657; E.O. 12777, 56 FR 54757, 3 CFR, 1991 Comp., p.351; E.O. 12580, 52 FR 2923, 3 CFR, 1987 Comp., p.193.

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Appendix B—[Amended]

2. Table 1 of Appendix B to Part 300 is amended under Delaware (“DE”) by removing the site name, Sussex County Landfill No. 5, and the city, Laurel, DE.

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[FR Doc. 01-18816 Filed 7-27-01; 8:45 am]

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