5 9 000

AMENDMENT TO THE1994 RECORD OF DECISION

LEXINGTON COUNTY LANDFILL SUPERFUND SITE. CAYCE, SOUTH CAROLINA

PREPARED BY:U.S. ENVIRONMENTAL PROTECTION AGENCY

REGION IVATLANTA, GA

5 9 ooo:DECLARATION FOR THE

RECORD OF DECISION AMENDMENT

Fundamental Change to the Selected Remedyin the 1994 ROD

SITE NAME AND LOCATION

Lexington County Landfill Superfund SiteCayce, Lexington County, South Carolina

STATEMENT OF BASIS AND PURPOSE

This amendment to the 1994 Record of Decision (ROD) document presents afundamental change to the selected remedial action for the Lexington CountyLandfill Superfund Site located in Cayce, South Carolina, chosen in accordancewith Comprehensive Environmental Response Compensation and Liability Act(CERCLA), as amended by Superfund Amendments and Reauthorization Act(SARA) and, to the extent practicable, the National Contingency Plan. Thisdecision is based on the Administrative Record for this Site. The State of SouthCarolina concurs with the amended remedy.

ASSESSMENT OF THE SITE

Actual or threatened releases of hazardous substances from this Site, if notaddressed by implementing the response action selected in this ROD Amendment,may continue to present an imminent and substantial endangerment to publichealth, welfare, or the environment.

DESCRIPTION OF THE MODIFIED REMEDY

The purpose of this ROD Amendment is to announce a modification of the remedyfor the Old Cayce Dump. The major components of the modified remedy include:

• In-Place containment of the Old Cayce Dump which is comprised ofapproximately 118,000 cubic yards of waste;

• Installation of a low permeability cover or cap;

• Installation of a subsurface leachate collection system which redirectsleachate to the existing groundwater collection system, and;

• Installation of a landfill gas management system.

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STATUTORY DETERMINATIONS

The modified remedy is protective of human health and the environment,complies with Federal and State requirements that are legally applicable or relevantand appropriate to the remedial action, and is cost-effective. This remedy utilizespermanent solutions and alternative treatment technologies to the maximum extentpracticable for this Site, and satisfies the statutory preference for remedies thatemploy treatment that reduce toxicity, mobility, or volume as a principal element.

Richard D. GreenDirectorWaste Management Division

Date

5 9 000Lexington County Landfill Superfund Site______________ Page 4

1.0 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.1 SITE NAME AND LOCATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.2 PUBLIC PARTICIPATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.3 1993 RECORD OF DECISION . . . . . . . . . . . . . . . . . . . . . . . . . . 81.4 SUMMARY OF THE CIRCUMSTANCES LEADING TO THIS

AMENDMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81.5 ADMINISTRATIVE RECORD . . . . . . . . . . . . . . . . . . . . . . . . . . . 91.6 ADMINISTRATIVE RECORD AVAILABILITY . . . . . . . . . . . . . . . . . 9

2.0 COMPARISON OF THE 1994 ROD TO THIS ROD AMENDMENT . . . . . . . 9

3.0 EVALUATION OF THE AMENDED REMEDY . . . . . . . . . . . . . . . . . . . . . 93.1 Overall Protection of Human Health and the Environment . . . . . . 103.2 Compliance with ARARs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103.3 Long-term Effectiveness and Permanence . . . . . . . . . . . . . . . . . 113.4 Reduction of Toxicity, Mobility, or Volume . . . . . . . . . . . . . . . . 113.5 Short-term Effectiveness . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123.6 Implementability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123.7 Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133.8 State Acceptance . . . . . . . . . . . . . . . . . . . . . r . . . . . . . . . . . 143.9 Community Acceptance . . . . . . . . . . . . . . . . .•-.—— . . . . . . . . . 14

4.0 STATUTORY DETERMINATIONS . . . . . . . . . . . . . . . . "."."." . .".". ... 14

Appendix A Public Meeting TranscriptAppendix B EPA Response to Public CommentsAppendix C State Concurrence Letter

Lexington County Landfill Superfund Site___________________PageS

1.0 INTRODUCTION

1.1 SITE NAME AND LOCATIONThe Lexington County Landfill Site (the "Site") is located in Lexington County, SouthCarolina (Figure 1). The Site consists of five properties and includes the 321 Landfill(a former municipal landfill), the Old Cayce Dump, and the Bray Park Dump (Figure 2).The 321 Landfill was formerly a sand mine excavated into the slope of a hill. Municipallandfilling operations began at the 321 Landfill in 1972 and ended in 1988 when thefacility reached capacity and was closed with a clay cap. The Old Cayce Dump and theBray Park Dump were used by local residences as refuse dumps. Dumping at the OldCayce Dump began in the 1940s. A portion of this dump was located in what wasformerly known as Stanley Pond. No topographic surface expression of the dump orformer pond is evident today. Both the Old Cayce Dump and the Bray Park Dump werecovered with soil in the early 1970s by Lexington County.

Waste disposal records for the Old Cayce Dump and Bray Park Dump are notavailable, however, disposal records for the 321 Landfill are available. Although themajority of the refuse in the 321 Landfill consisted of sanitary domestic waste, recordsindicate that certain types of industrial wastes were also disposed in the facility. Thesewastes included chemical solvents, petroleum products, and metallic wastes.

On April 14, 1992, an Administrative Order by Consent (AOC) was signed by LexingtonCounty. Under the terms of this AOC, Lexington County agreed to conduct a RemedialInvestigation (Rl) and Feasibility Study (FS) at the Site under the oversight of EPA. TheRl field activities began on June 30, 1992, and ended on September 14, 1992.

The Record of Decision (ROD) was signed on September 29, 1994. Negotiationsfor settlement regarding implementation of the Remedial Design/Remedial Action(RD/RA) began on October 8, 1994. A Unilateral Administrative Order was enteredon June 13, 1995.

1.2 PUBLIC PARTICIPATIONThe public participation requirements of both CERCLA Section 117 and Section300.435(c)(2)(ii) of the NCP have been satisfied. Fact sheets were sent topersons on EPA's Site mailing list on January 6, 1999. A newspaperadvertisement describing the proposed amendment and announcing the publiccomment period was placed in the local newspaper on January 8, 1999. A publicmeeting was held on January 14, 1999, at the Pine Ridge Town Hall. Thetranscript of the meeting is provided as Appendix A.

5 9 O O U 5

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APPROVED DATE11/93

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Lexington County Landfill Superfund Site___________________PageS

1.3 1993 RECORD OF DECISIONThe Record Of Decision (ROD) was signed by ERA on September 29, 1994, andutilized a presumptive remedy approach as presented in EPA's directive No. 9355.0-49FS. The applicability of the presumptive remedy at this site was based_on theexpectation that containment technologies would be appropriate for municipal landfillwaste, primarily because the volume and heterogeneity of the waste makes othertreatment technologies impracticable (Title 40 C.F.R. Section 300.430(a)(iii)(B))

Of the three waste areas, the Old Cayce Dump was identified as a waste areawhere containment was thought to be inappropriate due to its proximity togroundwater, its relatively small size, and ease of access for excavation purposes.For this reason the primary components in the 1994 ROD consisted ofconsolidating the Old Cayce Dump into the Bray Park Dump and capping the combinedwaste. The 1994 ROD also included capping the 321 landfill, landfill gas collection andventing, extraction and treatment of contaminated groundwater/leachate, followed byspray irrigation of treated groundwater atop the landfill to maintain the vegetative cover.

This ROD amendment will only address the portion of the 1994 ROD relating to theconsolidation of the Old Cayce Dump within the Bray Park Dump as all othercomponents of the 1994 ROD will remain in effect.

1.4 SUMMARY OF THE CIRCUMSTANCES LEADING TO THIS AMENDMENTInvestigation of the Old Cayce Dump in 1994 indicated its volume to be about 6acres in size with an average thickness of 12 feet. Groundwater elevations takenat that time revealed the bottom of waste to be between 2 to 3 feet below thewatertable. Such conditions would have allowed the dump to be excavated usingconventional methods and at moderate costs.

Pre-excavation engineering work performed in 1997 indicated that groundwaterlevels had risen so that the majority of the waste was beneath the water table.This condition was noted in EPA correspondence to Richardson & Associatesdated October 31, 1997. An estimated 3 million gallons of groundwater and/orleachate was present within the waste and would have to be managed beforeexcavating the waste. This represented a significant change in site conditionsrelative to the conditions under which the 1994 ROD was written.

Capital cost estimates for removing the waste under these conditions were$3,743,600 and represented a significant increase from the original capital costestimate of $1,460,000. For this reason EPA re-evaluated the remedial options forthe site through a Feasibility Study Report for the Old Cayce Dump. The resultspresented in the Feasibility Study Report for the Old Cayce Dump provided the

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Lexington County Landfill Superfund Site________________PageQ

justification ERA used in selecting the remedy.

1.5 ADMINISTRATIVE RECORDThe requirements set forth in Section 300.825(a)(2) of the NCP have beensatisfied. All documents that form the basis for the decision to amend the 1994ROD have been added to the Administrative Record.

1.6 ADMINISTRATIVE RECORD AVAIL ABILITY ~The Administrative Record is available for viewing by the public during regularbusiness hours at the following locations:

Cayce West-Columbia Library1500 Augusta RoadWest Columbia, South Carolina

US EPA Region IV Records Center61 Forsyth Street, SWAtlanta, Georgia 30303-3104(404) 562-8946

Copies of documents in the Administrative Record may also be obtained fromEPA's Region IV Records Center in Atlanta by writing to the Freedom-of-Information Act (FOIA) Coordinator and requesting a copy of the Lexington CountyLandfill Superfund Site Administrative Record Index. Choices of documents fromthe Index may be expressed in additional FOIA requests.

2.0 COMPARISON OF THE 1994 ROD TO THIS ROD AMENDMENTThe 1994 ROD evaluated cleanup options consisting of: no action, containmentwith institutional controls, containment with groundwater treatment, andconsolidation with groundwater treatment. This ROD amendment evaluatedcleanup options consisting of: no action, removal/ containment, in-placecontainment, in-place containment with groundwater cut-off wall, and-phytoremediation. The different alternatives evaluated as part of this RODAmendment were selected to better address the current groundwater conditions incontrast to the conditions prompting the 1994 ROD. New alternatives introducedwithin this ROD amendment include a subsurface cut-off wall (to containcontaminated groundwater), and phytoremediation (which uses trees to absorband contain contaminated groundwater).

3.0 EVALUATION OF THE AMENDED REMEDYThe following sections provide a detailed evaluation of this amendment against thenine criteria EPA uses to evaluate treatment technologies as required by law.These nine criteria are categorized into three groups consisting of threshold

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Lexington County Landfill Superfund Site__________Page 10

criteria, the primary balancing criteria, and modifying criteria. The threshold criteriaare comprised of 1) Overall protection of public health & environment and 2)Compliance with Applicable or Relevant and Appropriate Requirements (ARARs).The balancing criteria are comprised of 3) Long term effectiveness, 4) Short termeffectiveness, 5) Reduction of toxicity, mobility, & volume, 6) Ability toimplement, and 7) Cost. The modifying criteria consist of 8) Communityacceptance, and 9) State acceptance. The following section provides a summaryas to how the alternatives were evaluated against each of the nine criteria. Thisinformation can also be found in detail within the Final Feasibility Study Report forOld Cayce Dump, dated December 1998, under section 3.0 Comparative Analysisof Alternatives .

3.1 Overall Protection of Human Health and the EnvironmentThis criterion addresses whether the alternative will adequately protect humanhealth and the environment from risks posed by the site. Included in the judgementby this criterion is an assessment of how and whether the risks will be properlyeliminated, reduced, or controlled through treatment and engineering controls.

The remedy in the 1994 ROD (removal/containment) provides the most effectivemeans to control site risk by eliminating the potential risks associated with thedermal contact and ingestion of the soil, in addition to minimizing leaching togroundwater eliminating contact of the waste with the water table. The in-placecontainment alternative (both with or without the cut-off wall) would also beeffective in controlling the potential risks at the site through engineering controlsand would reduce or minimize leaching, but would not be as effective inminimizing leaching to groundwater as the removal/containment alternative. Theability of the phytoremediation alternative to control groundwater and leachateunder these site specific conditions is unlikely due to the depth of the water tableas well as the amount of water to be contained. For these reasons the ability ofthis alternative to adequately address site risks is questionable. The No-Actionalternative would not adequately address any of the site risks.

3.2 Compliance with ARARsThis criterion evaluates whether an alternative will meet all of the requirements offederal and state environmental laws and regulations, as well as other laws, and/orjustifies a waiver from an ARAR.

Maximum Contaminant Levels and/or risk based levels have been identified aschemical-specific ARARs for groundwater. The existing remedy (removal/containment) and the in-place containment alternative would be expected to meetall ARARs. The removal/containment remedy would accomplish this by removingthe waste source from groundwater. The in-place containment (both with or

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Lexington County Landfill Superfund Site__________________Page 11

without the cut-off wall) would attain compliance with ARARs by relying upon theeffectiveness of the groundwater recovery and treatment system, in addition tocapping, to achieve hydraulic containment. The Phytoremediation alternative maypossibly achieve ARARs due to natural attenuation and degradation, however, thetime period required for this to happen may be unacceptably long. This would alsobe the case with the No-Action alternative.

3.3 Long-term Effectiveness and PermanenceThis criteria evaluates the alternative's ability to maintain reliable protection ofhuman health and the environment over time, once the remediation goals havebeen met.

Both removal/consolidation and the in-place containment alternatives are capableof meeting this criteria. The removal/consolidation alternative does offer the bestmeans toward long-term effectiveness by removing the waste from the water tablethereby reducing the leaching of contaminants to' groundwater. The in-placecontainment alternatives (both with and without a cut-off wall) would have theability to adequately attain long term effectiveness and permanence throughcapping to control water infiltration as well as continued operation of thegroundwater treatment system to address contaminated groundwater. The in-placealternatives (both with and without a cut-off wall) would also require long-termmonitoring of groundwater, surface water and methane to ensure theeffectiveness of these actions. To ensure the long-term effectiveness of in-placecontainment, monitoring would be performed and the system enhancedaccordingly. Enhancements may include, but not be limited to, the installation oflarger capacity pumps in some recovery wells, or additional recovery wells.

The ability of the phytoremediation alternative to control groundwater and leachateunder these site specific conditions is unlikely due to the depth of the water tableas well as the amount of water to be contained. For these reasons the.ability ofthis alternative to adequately provide long-term effectiveness and permanence isquestionable. The No-Action alternative would not be effective in controllingsurface water infiltration and leachate discharge, and therefore not adequatelyattain long-term effectiveness and permanence.

3.4 Reduction of Toxicity, Mobility, or VolumeThis criterion addresses the anticipated performance of the treatment technologiesthat an alternative may employ. CERCLA, as amended, directs that where possibletreatment should be used to permanently reduce the toxicity of site contaminants,their migration, and/or reduce their volume.

None of the alternatives would be capable of reducing the toxicity or volume of

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Lexington County Landfill Superfund Site___________________Page 12

contaminants, however, to various degrees they would have some effect uponreducing the mobility of contaminants migrating from the waste via groundwater.Both the removal/containment alternative and the in-place containment alternativeswould reduce mobility of site contaminants through capping and utilization of thegroundwater treatment system. The removal/containment alternative would be themost effective alternative because it would also reduce the volume ofcontaminated groundwater leaching from the waste. This would be accomplishedby removing the waste from direct contact with the groundwater.

The ability of the phytoremediation alternative to reduce the mobility of waste, bycontrolling migration of groundwater and leachate under these site specificconditions is unlikely due to the depth of the water table relative to the limiteddepth the trees roots could penetrate. The No-Action alternative would not reducemobility of contaminants migrating from the waste via leachate or groundwater.

3.5 Short-term EffectivenessThe short term effectiveness criterion evaluates the length of time needed toachieve protection, and the potential for adverse effects to human health and theenvironment posed by implementation of the remedy, until remedial goals areachieved.

Both the removal/containment and the in-place containment alternatives (both withand without a cut-off wall) could be implemented within an acceptable period oftime with little potential for adverse effects to human health and the environment.The in-place containment alternatives would have the advantage of producingminimal impact to human health during implementation. The removal/containmentalternative would create potential for adverse health effects as well as animal andodor nuisances to workers and area residents.

Phytoremediation would require several growing seasons before its effectivenessin achieving protection could be measured. The potential for adverse effects tohuman health and the environment posed by implementation would be minimal.The No-Action alternative would have the least potential for adverse effects tohuman health and the environment during implementation yet would not beexpected to achieve an acceptable level of protection over time.

3.6 Implementability __Implementability considers the technical and administrative feasibility of analternative, including the availability of materials and services needed forimplementation.

The No-Action alternative and the in-place containment alternative would be

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Lexington County Landfill Superfund Site_______ Page 13

readily implementable, with the No-Action alternative requiring the least effort.Both of these alternatives utilize standard engineering practices which have beenreadily implemented at other sites with a minimum of difficulties. The in-placecontainment alternative utilizing the cut-off wall would be somewhat difficult toimplement due to the likelihood of encountering subsurface debris duringinstallation of the cut-off wall.

The removal/containment alternative is technically implementable yet would requiresubstantial effort to dewater the waste prior to excavation. The excavation of thelandfill contents would also require considerable resources due to the predictedmix of waste debris associated with landfills. The phytoremediation alternativewould involve earth moving and tree planting. The materials and technical servicesneeded for implementation of this alternative are readily available.

3.7 CostThe cost evaluation typically includes both the capital (investment) costs toimplement an alternative as well as the long term Operations & Maintenance(O&M) expenses applied over a projected period of time. Because all thealternatives evaluated utilize some form of containment, the time frame forcalculating O&M expenses can not be predicted with certainty. For estimationpurposes the O&M costs were evaluated using a 30 year time frame. The actualcost may likely exceed this 30 year time frame.

The following table presents an estimate of costs for all the options and is basedon 118,000 cubic yards of waste. The removal/containment option is considerablymore costly than the other options due to the expense associated with excavatingwaste below the water table.

Option

No Action

Phytoremediation

In-Place Containment

In-Place Containment withcutoff wall

Removal/Containment

Cost

$293,280

$595,000

$695,600

$1,021,000

$4,193,700

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Lexington County Landfill Superfund Site__________=_____Page 14

3.8 State AcceptanceThe South Carolina Department of Health and Environmental Control agrees withthis amendment although they have expressed concern over the potential forescalating operations and maintenance cost associated with leaving the waste in-place.

3.9 Community AcceptanceA thirty day public comment period began on January 8, 1999, and ended onFebruary 8, 1999. All comments received during this period, and EPA's responseto these comments, are included as Appendix B.

During the proposed plan public meeting one comment was made in favor of in-place containment. Another comment was expressed in favor of removal/excavation. EPA put the question to the audience asking for those in favor ofremoval/excavation to speak out. No one else within the audience commented ontheir desire for pursuing the removal/excavation alternative. Other issues notedduring the meeting included general comments expressing need for monitoringregardless of the alternative selected.

4.0 STATUTORY DETERMINATIONS

Based on the discussions presented within this document EPA will amend the RODfor the Lexington County Landfill Site from removal/containment to in-placecontainment for the Old Cayce Dump. This decision reflects the informationpresent in the Final Feasibility Study for Old Cayce Dump, the proposed plan publicmeeting, and comments received during the 30 day public comment period.

The amended remedy for this Site meets the statutory requirements set forth at Section121(b)(1) of CERCLA, 42 U.S.C. § 9621 (b)(1). This section states that the remedymust protect human health and the environment; meet ARARs (unless waived); becost-effective; use permanent solutions, and alternative treatment technologies orresource recovery technologies to the maximum extent practicable; and finally,wherever feasible, employ treatment to reduce the toxicity, mobility or volume of thecontaminants. The following paragraphs discuss how the remedy fulfills theserequirements.

The in-place containment remedy will remove the human health risks associated withexposure to contaminated waste, in addition to reducing the leaching togroundwater. It will also satisfy the ARARs listed in section 3.2 and any applicableARARs set forth in the 1994 ROD.

00

Lexington County Landfill Superfund Site__________________Page_1_5

Because the Old Cayce Dump is not the only waste source contributing togroundwater contamination at this site (i.e. the 321 Landfill, Bray Park Dump),groundwater remediation would be required regardless of the final disposition ofthe Old Cayce Dump. The amended remedy makes maximum use of the existingrequirement for pump and treatment system to support the in-place containment.The removal/excavation effort would require maximum efforts but only yield thesame level of protection as the in-place containment.

The in-place containment is more cost effective than removal/containment yet alsoprovides an acceptable level of long-term effectiveness. Monitoring will be performed toensure that in-place containment provides an acceptable level of long-termeffectiveness.

This approach represents the maximum extent to which permanent solutions andtreatment can practically be used for this site. In-place containment is considered apermanent solution and achieves the best balance of trade-offs in terms of long-termeffectiveness and permanence, reduction of toxicity/mobility/volume, short-termeffectiveness, implementability, and cost.

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-" =,

APPENDIX APUBLIC IVIEETING TRANSCRIPT

5 9 0 0

-H

APPENDIX BEPA RESPONSE TO PUBLIC COMMENTS

__59 001Response to Public Comments

Lexington County Landfill Superfund Site

The following comments were received by EPA during the 30 day public commentperiod for this site. The comments are presented chronologically and include EPA'sresponse to the comments.

1. Comment: Letter dated January 14, 1999, from John "Jake" Knotts, Houseof Representatives, Lexington County district no. 88. Representative Knottsexpressed concern over protecting private wells if waste within the OldCayce Dump was left in place. Rep. Knotts does not want residents to bearcost of tap-on fees if their private wells have to be abandoned due to themigrations of contaminated groundwater.

While acknowledging the $3.5 million saved in potential cost (through in-place containment) Rep. Knotts also noted that pumping will have tocontinue until the groundwater is contaminant free, which could be aninordinate amount of time. He is requesting that safeguards for drainage(from spray application) must be made to ensure that contaminated waterdoes not exceed the boundaries of the landfill.

Response: Because the Old Cayce Dump is not the only source contributingto groundwater contamination at this site (i.e. the 321 Landfill, Bray ParkDump), groundwater remediation will continue until contaminant levelsattenuate to safe levels. Containment of contaminated groundwater isconsidered a part of the original remedy and would remain as one of therequirements regardless of the disposition of the Old Cayce Dump. EPA willwork with Lexington County to ensure that the groundwater containmentsystem does an adequate job of containing contaminated groundwaterwithin the site boundaries.

With regards to the drainage from the spray application, all water enteringthe spray irrigation system will first be treated and tested within-the aerationpond. The water will then be sent to the spray irrigation system atop thelandfill only if it passes acceptable concentration limits.

2. Comment: Letter dated January 25, 1999, from Johnny W. Jeffcoat,Chairman, Lexington County Council. Chairman Jeffcoat writes to EPA tocomment on the ROD amendment and to respond to Representative Knottsletter dated January 14, 1999. Chairman Jeffcoat notes that the plan toleave the waste in place will save millions of dollars. His correspondencealso mentions Lexington County's responsibility to contain the contaminatedgroundwater and to modify the system as appropriate if future conditionswarrant such actions.

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Chairman Jeffcoat mentions the previous cost savings realized throughutilizing county employees to cap portions of the landfill and notes that thiswork was later contracted to private companies due to constructioncompletion time constraints.

Response: Because Chairman Jeffcoat's letter was presented to EPA inresponse to Representative Knotts letter, EPA has no specific response tothis letter other than to include it within the administrative record ascorrespondence received during the public comment period.

3. Comment: Letter dated February 2, 1999, from Tillman Rucker, residentadjacent to the Lexington County Landfill site. Mr. Rucker mentions his rolein notifying EPA about conditions at the landfill and also references thecommitment made by regulatory agencies in 1997 that the trash would beremoved. Mr. Rucker cited his knowledge of site conditions by locating anunderground water source, with support from Mr. Joel Player, which likelyfed the previous pond. Mr. Rucker also cited his involvement in draining thepond in the past.

This letter mentions that people did not seem to mind the smell of wastewhen they were dumping waste into the pond. Mr. Rucker also said that hehad to move his mother out of the area at times due to odor from thewaste.

Response: EPA would like to acknowledge the help Mr. Rucker has providedtowards discovering this site and the additional information he has providedon site specific issues. This help has been beneficial towards both theinvestigation and clean up effort at this site.

While it would be possible to de-water the Old Cayce Dump, in order toallow for excavation of the waste, the benefit in doing so is disproportionateto the additional cost. The relocation of the waste to another part of the sitewould not substantially reduce the risk posed to groundwater from thiswaste because the Old Cayce Dump is not the only waste sourcecontributing to the groundwater contamination at this site. The 321 Landfillas well as the Bray Park Dump also appear to contribute significantly togroundwater contamination. If the Old Cayce Dump was the only wastesource responsible for groundwater contamination at this site, EPA wouldhave pursued relocating the waste to another area.

Because the removal of one of the waste sources would not likely have asignificant impact upon improving groundwater conditions, relative to theeffort and cost required, EPA has proposed to amend the 1994 ROD to in-place containment.

6100 6 S

H E C 5 9 0020

2600 Bull StreetColumbia, SC 29201-1708

COMMISSIONER:Cougl» E. Btyant

BOARD:John H, 8uiri«Chairman

William M. Hull. Jr.. MDVice Chairman

SecretaryMark B. Kail

Cymli C. ModellerBrian K. Smith

Rodney L. Grandy

S P E R

Ai'ril29, 1999

Jo in H. Hankinson, Jr., Regional AdministratorU. 3. EPA, Region IVAt lanta Federal Center61 Forsyth St., SWAt .onto, Georgia 30303

RE: Lexington County Landfill Siiperfimd Site - ROD Amendment

Mr, Hankinson:

Th a Departmeni has reviewed the Amendment to the 1994 Record of Decision (ROD)dacd April 1999 forth* Lexington Cuunly Landfill site aud concurs with all parts ofth« remedy as stated in Ibis Amendment. The ROD Amendment pertains only to thatpo -tion of the site known as the Old Cayce Dump.

In concurring with this ROD Amendment, the South Carolina Department of Healthan> I. Environmental Control (SCDHEC) Uocs not waive any right or authority it mayha- 'e under federal or state law. SCDHEC reserves any right or authority it may haveto 'equire corrective action in accordance with the South Carolina Hazardous WasteMi nagement Act and the South Carolina Pollution Control Ar.t These rights itir.Uide,bu. arc not limited to, the right to ensure that all necessary permits are obtained, allule iui-up gudb auU wilcria are met, and to rake a separate action in the event clean-upgoils and criteria are not met Nothing in the'concurrence shall preclude theDe :)artmcnt from exercising any administrative, legal and equitable remedies availableto • squire additional response actions in the event that: (1) (a) previously unknown orun letected conditions arise, at the site, or (b) the Department receives additionalintimation not previously available concerning the premises upon which theDepartment relied in concurring with the selected remedial alternative; and (2) theim Dlementation of the remedial alternative selected in the ROD is no longer protectiveof labile health and the environment.

C A R O L I N A D E P A R T M E N T O F H E A L T H A N D B N V 1 R O N M E N T A L CONTRCIL

5 9 0021Mr. John II. Uzmkinson, Jr.Lexington Cou nty Lanfill - ROD AmendmentPage 2

SCDHEC conci us with the in-place containment remedy that will consist of capping the Old CayceDump and preventing offsite migration of contaminated ieachate, groundwater and surface waterusing hydrauli'1. containment provided by a groundwatcr recovery system. In addition, theDepartment co: icurs with treatment of contaminated groundwater/leachate in the onsite aerationbasin, followed :>y spray Jrrj.sation of treated groundwater atop the former Lexington County Landfillto maintain the vegetative cover. The Department also concurs with the proposals for verificationmonitoring oft le containment system and system enhancement, if necessary.

The Departmen :'s concurrence is contingent upon the in-place containment system preventing thedischarge of co nominated groundwater to surface water located south and west of the Old CayceDump, and uposi the results of verification monitoring to be conducted throughout the operation ofthe in-place con ainment system. Continued discharge of contaminated groundwater to surface waterwould be consk -sred as incomplete containment and would require that this discharge be regulatedby NPDES pern litting or additional response actions to include, but not be limited to, removal of thewaste. Since Nl iDES permitting may involve costly pre-treatment, the Department believes that thecosts of in-place containment will likely exceed the costs cited in the ROD Amendment. Dependingon the results o:' verification monitoring and the potential need for additional response actions, anExplanation of f lignificanl Differences (BSD) and/or ROD Amendment may be required. An BSDand/or ROD An endment would require The Department's concurrence. SCDHEC understands thatany and all othe; conditions of the i994 ROD, not affected by this 1999 ROD Amendment, remainunchanged. If you have any questions, please feel free to contact Mr. Gary Stewart at (803) 896-4054.

Sincerely,

R. Lewis Shaw, ,P.E.Deputy Commis aioncrEnvironmental < Quality Control

RLS/JAB

cc: Harry M ithisKeith Li: idlerGerald ShealyGary Ste wartFile #52 . 14 Lexington County Landfill Site

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