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Five-Year Review Report Island Chemical Corp.A^irgin Islands Chemical Corp, Superfund Site EPA ID: V1D980651095 St Croix, US Virgin Islands SDMS Document ililllll 103674 r.'. i-'-.'„..- 4fpy, x^s. .•• . r * " * ' * < > * " *«H«,i,*f Prepared by: United States Environmental Protection Agency Region 2 New York, New York March 2009 Table of Contents Executive Summary iii Five-Year Review Summary Form iv I. Introduction 1 II. Site Chronology • 1 III. Background 2 Physical Characteristics Geology/Hydrogeology Land and Resource Use History of Contamination Initial Response Basis for Taking Action IV. Remedial Actions 4 Remedy Selection Remedy Implementation Institutional Controls System Operations/Operation Maintenance Remedy Costs V. Five-Year Review Process 8 Administrative Components Community Involvement Document Review Data Reviewf Site Inspection Interviews Institution Control Verifications & Effectiveness VI. Technical Assessment 11 Question A: Is the remedy functioning as intended by the decision documents? Question B: Are the exposure assumptioas, toxicity data, cleanup levels, md remedial action objectives (RAOs) us«J at the time of the remedy still valid? Question C: Has any other information come to light that could call into question the protect iveness o f the remedy? -1- VII. Recommendations and Follow-up Actions 12 VIII. Protectiveness Statcnient(s) 12 IX. Next Review 13 Tables Table 1 - Chronology of Site Events 14 Table 2 - Documents Reviewed 15 Table 3 - List of Acronyms Used In Thfe Document 16 -11- EXECUTIVE SUMMARY rhis is the first five-year review tor the Island Chemical Corp./Virgin Islands Chemical Corp. Supertlmd site. Six iu*eas of potential concern were investigated during the initial assessment and the subsequent Remedkil Investigation (Rl), along with the nature and extent of soil and groundwater contamination, and potential oft-Site sediment contamination. Based on the data colltxted, only the Alx»ve Ground Storage Tank Area (AST) and Former Process Pit (FPP) areas were determined to rt^iuire remediation. Contaminants of concern (COC) at the Site included ethylbenzene and xylene in si>iis and groundwater at the AST Area and chlorotbrm in groundwater at the FPP area. Currently, this site has no hazardous substances, associated with the National Priorities List (NPL) release, remaining above levels that would prevent unlimited use and unrestricted exposure. The remedy is considered to be complete and is protective of human health and the environment. -in- Five-Year Review Summary Form SITE IDENTIFICATION Site Name (from WastsLAN): Island Chemical Corp.A/irgin Island Chemical Corp. EPA ID (from WasteLAN): VID980651095 Region: 2 State: USVI City/County: Estate Bethlehem, St. Croix SITE STATUS NPLS^tUs: BRnal I D Delet«i D Othw (specify) Remediation Status (choose all that apply): • Under Construction D Operating Complete MulMple OUs? D YES • NO Construction completion date: 3/2004 Has sit© been put into reuse? D YES D NO • N/A (site reuse has not been determined) REVIEW STATUS Lead agency: • EPA • State D Tribe D Other Federal Agency Author name: Caroline Kwan Author title: Remedial Project Manager Author affiliation: EPA Review period: 3/2004 to 3/2009 Date(s) of site inspection: Typo of review: DPost-SARA DPre-SARA Q NPL-Removat only D Non-NPL Remedial /tetion Site D NPL State/Tribe- lead D Regional Disaetion • Policy Review numt>er: • 1 (first) D 2 (second) D 3 (third) a Otha-(specify) Triggering action: D Actual RA Onsite Construction D Actual RA Start • Construction Completion D Previous Five-Year Review Report g Other (specify) . Triggering action date (ftvm Wa^^JKN): March 24. 2004 Due date (five years after triggering action date): March 24,2009 Does the report include recommendation(s) and follow- up action(s)? D yes • no Acres in use or suitable for use: restricted: unrestricted; 3.5 -IV- Five-Year Review Summary Form (continued) Recommendalions and Folluw-Up Actions There are no recommendations or follow-up actions. Post Remediation Monitoring has been completed at the site. The PRPs have demonstrated in their certification of completion and their tmal post remediation monitoring report that the site pertbmiance stjmdards have been achieved. Cleanup goals have been reached at both areas of the site which were subject to remediation. Further EPA has determined that the cleanup goals achieved are protective of all reasonably anticipated site uses and exposures. Protectiveness Statement Remedial action objectives have been achieved so that human health and the environment are protected under all reasonably anticipated site uses and exposure. No fiirther five-year reviews are required by Section 121(c) of CERCLA, EPA regulations or EPA policies. I. Introduction This first five-year review for the Island Chemical Corp./Virgin Islands Chemical Corp. (VICHEM) Super&nd site, was conducted by United States Environmental Protection Agency (EPA) Remedial Project Manager (RPM) Caroline Kwan. The five-year review was conducts! in accordance with the Comprehensive Five-Year Review Guidance, OSWER Directive 9355.7- 03B-P (June 2001). The purpose of five-year reviews Is to ensure that implemented remedies protect public health and the environment and function as intended by the decision documents. This document will become part of the site file. In the Remedial Design/Remedial Action (RD/RA) Consent Decree, the PRPs agreed to perform the RD/RA specified in the ROD. On a voluntary basis, the PRPs had been operating the soil vapor extraction/air sparging (SVE/AS) system in the AST Area (which was consistent with the requirements of the ROD) since 200!, and an extensive network of nwnitoring wells was already in place. A formal remedial design pfiase was, therefore, not required by the Consent Decree, except in the event EPA detennined that supplemental activities were required to achieve performance standards. The following are all elements of the requirai remedial action: • Remedial Element I; Soil Vapor Extraction/Air Sparging (SVE/AS) tor the AST Area; • Remalial Element II: Monitored Natural Attenuation (MNA) for the FPP Area; and, • Reinerfial Element III: Institutional Controls. EPA conducted the Pre-Final Inspection of remedial instruction activiti« in March 2004. Remedial construction activities were considered cotnplete during this inspection. Because the completion of the remedy will not leave hazardous substances, pollutants, or contaminants on site above levels that allow for unlimited use and unrestricted exposure, a policy five-year review (rather than a statutory five-year review) is required. In accordance with the Section 1.3.2 of the five-year review guidance, a policy five-year review is triggered by the constmction complete This five-year review provides background information, covers the site history, discusses past data- collection efforts along with information collected in the past five years, and reevaluates risk and remedy protectiveness based on updated assumptions. This five-year review evaluat«l the remedial action and found that the implemented remedies protect human health and the environment. II. Site Chronology Table I (attache!) suinmarizes the site-related events from discovery to post remediation monitoring. -1- III. Background i^hysical Characteristics The VICHEM Site is located on Plot 13Q of Estate Bethlehem Middle Works in the south-central portion of St. Croix in the U.S. Virgin Islands. Plot 13Q is bordered to the north and east by an intemiittent stream. The River Gut, which originates north of the Site, drains to the Caribbean Sea. Site Geology/Hydrogeology The site lithology consists of fill material tirom ground surface to approximately 10 feet betaw ground surface (fogs), underlain by 80 feet of brown and gray clay-rich alluvial sediments. Local lenses of permeable gravel and sand are located at approximately 30 to 40 tbgs. Underlying the alluvium is the white to light brown and gray, lime-rich, stiff clay of the Kinphill Formation. The site contains two water bearing zones; the shallow alluvium from 0 to 50 tbgs and the deep alluvium from 50 to 100 fogs. Depth to water varies from 10 to 30 fogs depending on annual precipitation cycles (the wet season typically extends from August throuj^ November). Groundwater flow is south - .southeasterly with a horizontal gradient of approximately 0.002 - 0.014 ft/ft in the shallow alluvium and 0.003 - 0.014 ft/ft in the deep alluvium. A downward vertical gradient of approximately 0.005 - 0.11 fl/ft exists between the two zones. Monitoring wells screened in the shallow zone typically do not show a response to off-site pumping, while wells screened in the deep zone show significant response. Based on this difference, it is believed an aquitard exists between the shallow and deep alluvium that prevents contaminant migiation. Land and Resource Use Land use surrounding the VICHEM Site includes a mix of commercial and industrial purposes and the Site is zoned as 1-2 (Light Industry). History of Conlumination Charles 11. Steffey, Inc. (CHS, Inc.) purchased the VICHEM Site in 1968. At some point prior to 1969, CHS, Inc. changed its name to CHS Holding Corporation (CHS). From 1968 to 1982, the Site was used for the manufacture and blending of a variety of pharmaceutical products. By the end of 1982, the facility was pennanently closed. CHS retains ownership of the Site. Between 1984 and 1991, .several investigations were conducted at the Site by EPA and a former tenant, Island Clicmical Company, which was later acquired by Berlex. This investigative work identified six areas of potential environmental concern: • Laboratory and Warehouse Building; • Above ground storage tank (AST) area; • Former process pit (FPP) area; • Losing dock/former laboratory pit area; • Soil beneath concrete pad near ASTs; • Concrete storage pad. On May 31, 1990, EPA filal a Notice of Comprehensive Environmental Response Compensation, and Liability Act (CERCLA) lien on the Site property pursuant to Section 107(1) of CERCLA, 42 U.S.C. § 9607(1), to secure payment for the costs incurred in the performance of the removal action at the Site. On September 29, 1994, EPA entered into an Administrative Order on Consent (AOC), Index No. II CERCLA-94-0401, with Berlex and Island Chemical Company; Pierrel S.p. A, a subsidiary of Pharmacia &Upjohn (P&U) and also a former tenant at the Site, was added as a res|x>ndent to the AOC in April 1999. The AOC, pursuant to Section 106(a) of the CERCLA, as amended, 42 U.S.C. '9606(a), required the pwformance of a Remedial Investigation/Feasibility Study (RI/FS) at the Site. The priinary objectives of the Rl were to: 1) collect the data needed to characterize the nature and extent of contamination and adequately support human health and ecological baseline risk . assessmmts and 2) provide a basis on which a subsequent remedial action plan would be recommended. All six areas of potential concern were investigated during the iiiitial a.ssessment and the subsequent Ri, along with the nature and extent of soil and groundwater contamination, and potential ofF-Site sediment contamination. Based on the data collected, only the AST and FPP areas were determined to require remediation. EPA added the VICHEM Site to the National Priorities List (NPL) on June 17, 1996. initial Response During initial stages of site ass^isment, both EPA and Berlex ajnducted response activities including soil excavation with on-Site treatment or ofF-Site disposal, drum removals, and off-Site disposal of AST contents. Between September 1989 and October 1991, EPA conducted a removal action at the Site. At that time, the laboratory/warehouse building was found to contain approximately 400 drums (some extremely deteriorated), leaking cylinders of chlorine ajid hydrogen chloride, and over 800 containers of laboratory reagents that included sodium metal, potassium cyanide, and ethyl ether. EPA removed 354 drums containing 14,720 gallons of various chemicals and 8,061 pounds of lab pack chemicals from the laboratory/warehouse building and disposed of these materials ofF-Site. Basis for Taking Action Contammmits of concern at the Site as detennined in the RI included ethylbenzene and xylene, in soils and groundwater at the AST Area and chlorotbrm in groundwater at the FPP area. The risk assessment determined that the Site posed potential threats to human health and the environment through ingestion associated with contaminated soil £ind groundwater. -3- IV. Remedial Actions Remedy Selection As part of the RI/FS, the PRPs implemented a field Pilot Test of SVE/AS in February 2000. Following successful completion of the Pitot Test, and with the approval of EPA and the Virgin Islands Department of Planning and Natural Resources (VIDPNR), a SVE/AS s}^tem tor the AST Area was placed in continuous operation in June 2001 by the PRPs. A chain link fence was installed in spring 2000 along the property line to secure the area fi"om unauthorized access, and in the spring of 2002, the PRPs demolished the site buildings rod removed and disptised/recycled all of the tanks and related equipment. On August 14, 2002, the Regional Administrator signed a Record of Decision (ROD) selecting the tbltawing remedy: • SVE/AS to treat contaminated groundwater, saturated soil, and uasaturated soil at the .A.ST source area; • MNA to address low-level residual contamination in groundwater at the FPP area and downgradient areas; and • Institutional controls (in the fonn of existing VIDPNR well permitting laws and regulations) to limit the pumping of groundwater at the Site to prevent interference with the selected remedy and to also prevent human exposure to contaminated groundwater until EPA's Maximum Contaminant Levels (MGLs) are achieved. The ROD also sel«:ted groundwater pump and treat as a contingency remedy in the event that groundwater cleanup goals were not achieved in a reasonable time period. The cleanup goals tor soils in the AST Area were 6,500 ug/kg for ethylbenzene and 90,000 ug/kg tor xylene; these values were selected with consideration of commercial land use and impact to groundwater. The unrestricted residential soil cleanup goals are 5,700 ug/kg for ethylbenzene and 600,000 ug/kg for xylene. The post-excavation .sampling conduct^ by Oolder Associate! indicates that the maximum detected concentration of ethylbenzene In soils is 1,600 ug/kg at a depth of 8 feet and that the maximum detected concentration of xyloxe in soils is 1,3(K) ug/kg at a depth of 11 feet. Therefore, the concentrations of site-related contaminants remaining in soils are below the level that allows unrestricted residential land use. For groundwater, the cleanup goals were 700 /ig/L for ethylbenzene, 10,000 ^g/L for xylene, and 100 /ig/L for chloroform, respectively. All groundwater monitoring locations have been below the cleanup goals. -4- The following RAOs based on the human health risk assessment were required for the site: • Mitigate the toxicity, mobility, and/or volume of volatile organic compounds (VOCs) (ethylbenzene and xylene) in soils in the AST Area so as to minimize continued leaching to groundwater; • Mitigate the toxicity, mobility, and/or volume of VOCs (ethylbenzene and xylene) in groundwater in the AST Area and downgradient so as to achieve MCLs <md protect potential future groundwater users; • Mitigate the toxicity, mobility, and/or volume of chlorofbnn in groundwater in the FPP area and downgradient so as to achieve MCLs and protect fiiture potential groundwater users; and • Restrict on-Site groundwater use to non-potable purposes until the water quality is restored to MCLss, In the RD/RA Consent Decree, the PRPs agreed to perform the RD/RA specified in the ROD. On a voluntary basis, the PRPs had been operating the SVE/AS system in the AST Area (which was consistent with the requirements of the ROD) since 2001, and an extensive network of monitoring wells was already in place. A forma! remedial design phase was, therefore, not required by the Consent Decree, except in the event EPA determined that supplemental activities were required to achieve performance standards. The PRPs submitted a Remedial Action Work Plan (RAWP) in September 2004 that details all elements of tlie required remedial action; • Rerrwiial Element 1: Soil Vapor Extract ion/Air Sparging (SVE/AS) for the AST Area; • Remedial Element II: Monitored Natural Attenuation (^4NA) for the FPP Area; and, • Ranedial Element 111: Institutional Controls. Remedy Implementation SVE/AS System in AST Area The SVE/AS system included sbt SVE wells, one AS well, and eleven vapor monitoring probes, together with a surface vapor barrier that prevented short-circuiting of air flow and direct contact with surface soil. A groundwater monitoring network comprising a total of eight wells (shallow and deep) was also installed in the AST Area Continuous operation of the SVE/AS system by the PRPs fixjm June 2001 through November 2003 removed approximately 2,030 pounds of AST Area contaminants and reached asymptotically low limits of mass removal. Rebound testing indicated that negligible residual mass was left in the unsaturated zone. The mass removed correlate well with source mass estimates presented in the Feasibility Study (FS) of 1,900 pounds. AST Area Groundwater Sampling Results up to June 2004 AST Area groundwater has been monitored quarterly commencing in June 2001, when the SVE/AS system was placed in continuous operation, including three events subsequent to shut down of the AS/SVE system on November 3, 2003. Groundwater concentrations were reduced from a high of 176,000 ug/L of total toluene, ethylbenzene and xylene (TEX) in June 2001 -5- (baseline levels) in the most contaminated well (MW 6), to 13 ug/'L in SeptenAer 2003, the last sampling event prior to the November 2003 shutdown of the SVE/AS system. Four other AST Area groundwater monitoring locations remained below the ROD cleanup goals for the entire period, Jind were generally at or near non-detect levels from November 2001 onward. Rebound and p{)st shut down evaluations performed in August 2002, December 2003, March 2004 and June 2004 indicated modest increases in groundwater concentrations, to levels generally below cleanup goals. Post shutdovwi levels in MW 1 and MW 6 in June 2004 were r^uced 99.99% from baseline concentrations in June 2001, confirming the permanence of the remediation. Concentratioas in MW 6 decreased from 6,900 ug/L of TEX in December 2003 to 14 ug^'L of TEX in June 2004. The concentrations in MW 1, which increased from December 2003 to March 2004, had decreased since March 2004, as natural attenuation degraded the residual contaminant concentrations following source removal/treatment of the vadose zone (2,035 pounds removed via SVE). Prior to source mass removal in the AST Area, the extent of groundwater impacts were relatively limited (approximately 30 to 40 feet downgradient) due to natural attenuation processes. Wells located to the north of the AST Area, MW 8 and MW 10, were imtalled during the Remedial Investigation (RI) to monitor the possible off property nagration of contaminants although the predominant groundwater flow direction is to the south/southeast. These wells were sampled during the baseline event smd in the three evaits since December 2003. In each event, concentrations of TEX were 0.6 ug/L in MW 8 and MW 10, indicating that there is no migration of Site COCs to the north. AST Confirmatory Soil Sampling Soil samples were collected in the AST Area on a 25 foot by 25 fbot grid pattern with vertical samples collected every 2 feet to the water table, in February 2004 and analyzol tor site contaminant VOCs. The results demonstrated that contaminant levels were below cleanup goals in all samples analyzed. The highest depth averaged concentrations of soil samples in one location were 369 ug/kg of ethylbenzene and 296 ug/kg of xylene, compared with the ROD cleanup goals of 6,500 ug/kg and 90,000 ug/kg, respectively. Groundwater monitoring was performed semi annually from 2004 to 2006. Three wells, MW-1, MW-6, and AST-VMP-3D, were monitored in the AST Area for TEX parameters and a list of key intrinsic biodegradation parameters. All FEX results were befow cleanup goals except tor one detection of ethylbenzene at 1700 ug/L in December 2004. EPA approved annual post remediation monitoring in the AST Area in April 2006. TEX concentrations have remained below cleanup goals during three rounds of post remediation monitoring from 2006 to 2008. The data is reported in the Final Post Remediation Report. Since post remediation monitoring showed compliance with clesmup goals, no further sampling of the monitoring wells is expected in the AST Area. -6- MNA in FPP Area EPA selected monitored natural attenuation (MNA) as the remedy for FPP Area groundwater, and chloroform concentrations in groundwater have decreased sharply since 1998 such that the cleanup goal has now been reached. From 1998 to June 2004, chloroform in MW-2, the source area of historically highest concentrations, decreased from 2,400 ug/L to 13 ug/L. Chloroform concentratfons in the FPP Area have been consistently below the cleanup goal since 2000. MW- 11, a downgradient well which had an increase in chlorofbnn from 3J ug/L in 1998 to 40.4 ug/L in 2000, was below cleanup goals in 2004, indicating that chloroform has attenuated downgradient. Chtoroform was not been detected in any of the AST Area wells, and methylene chloride (a potential degradation product of chlorofonn) was not detected above 1 ug/L in any FPP or AST welLs up to June 2004. In the FPP area, annua! post remediation groundwater rronitoring began in the 2nd quarter 2005. Three wells, MW-2, MW-7, and MW-II, were monitored for chloroform. Chloroform concentrations have remanied below cleanup goals during three rounds of post remediation monitoripg from 2005 to 2007. The data is reported in the Final Post Ranediation Report. Since post remediation monitoring showtxi compliance with cleanup goals, no fiirther sampling of the monitoring wells is expected in the FPP Area. ROD Cleanup Goals Achieved Based upon the soil and groundwater data, which indicated rompliance with all cleanup goals, EPA determined that supplemental remedial construction activities were not necessary, and use of the contingency remedy of groundwater pump and treat would not be required in either the AST Area or FPP Area. EPA conducted the Pre-Final Inspection of remedial construction activities in March 2004. Remedial construction activities were consklered complete during this inspection. Subsequent Post Remediation groundwater monitoring at both AST and FPP Areas showed that compliance with all cleanup goals have beai met. The Final Post Remediation Monitoring Report was submitted to EPA on April 28, 2008. Institutional Controls The ROD indicated that the VIDPNR, in consultation with EPA, would utilize institutional controls (in the form of existing well permitting laws and regulations) to limit the pumping of groundwater at the Site, to prevent interference with the selected remedy, and to also prevent human exposure to contaminated groundwater until ROD cleanup goals are achieved. Pureuant to the CD, on request from EPA, the PRPs were to execute and record an easement to provide access to the Site and ensure that groundwater was not used for potable purposes and activities at the Site would not interfere with the remedy. The PRPs maintained fencing around the site and maintained oversight of groundwater conditions during remediation. The PRPs worked with VIDPNR to ensure that no wells were installed or used for the duration of the remediation. Based ujxm the confirmatory groundwater sampling data, which indicate meeting or -7- cxcccdijig all cleanup goals for both soils and groundwater, EPA did not require the filing of an casement. The site is considered suitable for unlimited use and unrestricted exposure (UU/UE) and the use of institutional controls in the future is not wartanted. No reuse is known to be currently planned for the Site. The property is currently up for sale. System (}perations/Operation and Maintenance There are no fiirther operation and maintenance activities associated with this site. The PRPs will properly seal all remaining nwnitoring wells and discontinue remedy components, as appropriate. There were no institutional controls implemented for this site and no follow-up activities associated with the institutional controls. Following issuance of this report, EPA will seek the Virgin Islands concurrence on the deletion of this site from the NPL. Remedy Costs The ROD estimate of costs for the Selected Remedy was as follows: Capital costs: $ 850,760. Estimated present worth O&M costs: $ 553,500. Total estimated present-worth cost: $ 1,404,260. The PRPs bcurred capital costs tor remedy implementation of approximately $600,000. Operation and maintenance costs $573,000 to date and have included: • SVE/AS system operation • Maintenance and monitoring tor 30 montlis • Quarterly and post-remediation groundwater sampling and reporting for 48 months, and • Confirmatory soil sampling, V. Progress Since the Last Five-Year Review This is the first five-year review for the site. VI, Five-Year Review Process Administrative Components The five-year review team consisted of: Michael Sivak: EPA Risk .Assessor .Amanda Gallgaher: EPA geologist Caroline Kwan: EPA RPM Syed Sadaydeli: VIDPNR RPM -8- Community involvement The EPA Community Involvement Coordinator (CIC) for the Virgin Islands Chemical site is, Cecilia Echols. A public notice in The St. Croix Avis was published on February 6, 2009, notifying the community of the initiation of the five-year review process. The notice indicated that EPA would be conducting a five-year review of the remedy tor the Site to ensure that the implemented remedy remains protective of public health and is functioning as designed. It was also indicated that once the five-year review is completed, the results will be made available in the local site repositories. In addition, the notice included the RPM's and the CIC's addresses and telephone numbers for questions related to the five-year review process for the Virgin Islands Chemical site. There were no comments received from the public or from stakeholders during this review. The Region's community involvement staff'conducted an active campaign to ensure that the residents were well informed about the activities at the site. Community involvement activities included routine publication of progress fact sheets. Document Review The documents, data, and intbrmation which were reviewed in completing the five-year review are summarized in Table 3 (attached). Data Review Groundwater Monitoring Twelve groundwater monitormg events have been conducted at the site during the review period (2003 - 2008). Groundwater monitoring has been conducted according to the 2002 Rerord of Decision and Consent Decree, and the associated 2004 Statement of Work. Groundwater elevation measurements and natural attenuation parameters (temperature, pH, specific conductance, turbidity, dissolved oxygen, and redox potential) were collected during each event. Groundwater samples were submitted for analysis of toluene, TEX in the AST Area, and chloroform and methylene chloride in the FPP Area. Post Remediation Monitoring groundwater sampling was discontinued May 2007 in the FPP Area and February 2008 in the AST Area. Alx>veground Storage Tank Area The selected remedy for groundwater contaminants in the AST Area is treatment via SVE/AS. The SVE/AS system was .shut down on November 3, 2003. Prior to system shut-down, COC, TEX, were below MCLs The MCLs for ethylbenzene and xylene are 700 parts per billion (ppb) and 10,000 ppb, respectively. Following shut-down, COC concentrations rebounded in .AST Area wells MW-1, MW-6, and AST-VMP-3D, but are currently showing decreasing trends. MW-1 Ethylbenzene concentrations in groundwater increased to above the MCL in Spring 2004, but then declined during subsequent sampling seasons. Currently concentrations arc below the MCL. Xylene concentrations increased to levels above the MCL from December 2003 through June -9- 2004 then declined to below the MCL in November 2005 and subsequent sampling events showed contaminant levels continued to remain below MCLs. .MW-6 Concentrations of ethylbenzene rebounded to levels above the MCL in December 2003, but have since shown a declining trend. Concentrations have been below the MCL since the March 2004 sampling event. Concentrations of xylene also rebounded post remedial shut-down, but have remained below the MCL since 2001. AST-VMP-3D Although concentrations of TEX rebounded slightly post system shut-down, ethylbenzene has remained below the MCL during the review period. Concentrations of xylene increased to levels above the MCL in December 2004, but Irnve subsequently decreased. Currently xylene concentrations are below the MCL. Subsequent sampling events showed contaminant levels continuetl to remain below MCI.S, Former Process Pit Area EPA selected monitored natural attenuation (MNA) as the remedy for FPP Area groundwater, and chloroform concentrations in ip-oundwater have decreased sharply since 1998 such that the cleanup goal has now been reached. From 1998 to June 2004, chloroform in MW-2, the source area of historically higliest concentrations, decreased from 2,400 ug/L to 13 ug/L. Chloroform concentrations in the FPP Area have been consistently below the cleanup goal since 2000. MW- 11, a downgradient well which had an increase in chloroform from 3J ug/L in 1998 to 40.4 ug/L in 2000, was below cleanup goals in 2004, indicating that chloroform has attenuated downgradient. Chloroform has not been detected in any of the AST Area wells, and methylene chloride (a potential degradation product of chlorofonn) was not detected above 1 ug/L in any FPP or AST wells up to June 2004. In the FPP area, annual pt)st remediation groundwater monitoring began in the 2nd quarter 2005. Three wells, MW-2, MW-7, and MW-ll, were monitored for chlorotbrm. Chlorofbnn ct)nccntrations have remained bclov? cleanup goals during three rounds of post remediation monitoring from 2005 to 2007 and have not migrated downgradient. The data are reported in the Final Po.st Remediation Report. Since post remcdiatbn monitoring showed wmpliance with cleanup goals, no further sampling of the monitoring wells is planned in the FPP Area. Site Inspection Site inspections were performed on Mtirch 4, 2009. -10- Inspection participants included: Caroline Kwan- EPA-RPM Dr. Nadine Noorhasan Director of DEP, VIDPNR Syed Syedali- VIDPNR Emanual Liburd- VIDPNR WiUiam Gierke- RPM, Pfizer, Inc. Steve Kemp- Pfizer, Inc. Allen Kane- GoMer Associates Wcs Jamison- CariWjean Hydro-Tech Inc. Institutional Co'ntrok Verification and Effectiveness There were no institutional controls implemented for this site and no follow-up activities associated with the institutional controls. V!. Technical Assessment Question A: Is the remedy functioning as intended by the decision documents? The Remedial Action Objectives include: 1.) mitigating the toxicity, mobility, and/or volume of ethylbenzene and xylene in the soils of the AST Area in order to minimize leaching potential and in the groundwater at and downgradient of the AST Area so as to reach MCLs; 2.) mitigating the toxicity, mobility, and/or volume of chtoroform in groundwater at and downgradient of the FPP area .so as to reach MCLs; and 3.) to restrict potable use of groundwater until MCLs are achieved. All recent groundwater data indicate that MCLs have been achieved at the site. The remedy has fiinctioned as intended and these remedial action objectives have been achieved. Question B: Are the exposure assumptions, toxicity data, cleanup levels, and remedial action objectives used at the time of the remedy stUI valid? There are no changes ki the physical conditions of the site or site use? that would affect the protectiveness of the selected remedy. The exposure assumptions and the toxicity values that were used to estimate the potential risks and hazards to human health followed the general risk assessment practice at the time that the risk assessment was performed. Although the risk assessment process has been updated in recent years and specific parameters and toxicity values have changal, the risk assessment process that was used is still consistent with current practice and the need to implement a remedial action remains valid. Cleanup goals for soil remain valid. It should be noted that the cleanup goals for soils in the AST Area are 6,5(K) ug/kg for ethylbenzene and 90,000 ug/kg for xylene; these values were selected with consideration of amimercial land use and impact to groundwater. The unrestricted residential soil cleanup goals are 5,700 ug/kg for ethylbenzene and 600,000 ug/kg for .Kylene. The post-excavation sampling amducted by Colder Associate indicates that the maximum detected concentration of ethylbenzene in soils is 1,600 ug/lcg at a depth of 8 feet and the maximum detecttxl concentration of .xylene in .soil is 1,300 ug/kg at a depth of 11 feet. Therefore, the concentrations of site-related contaminants remaining in soils are betow the level that allows unrestricted land use. Cleanup goals for groundwater are MCLs. The evaluation of groundwater in this five-yeai- review focusetl on the ix)ssibility of vajxir intrusion if buildings were to be constructed at the site. Soil vapor intrusion was not evaluated in the original risk assessment. This pathway was evaluated for this Five-Year Review to detennine if vapor intrusion concerns are present. Since groundwater concentrations at all monitoring wells meet MCLs, the potential for vapor intrusion is not anticipated. Exceeding soil cleanup levels and meeting MCLs in groundwater COCs have achieved an unrestricted use and unlimited exposure determination for the site. As a result, no long-teim Institutional Controls (IC) or operatfon and maintenance activities are necessary. Question C: Has any other information come to light that could call into question the protectiveness of the remedy? No. Technical Assessment Summary Based upon the results of the five-year review, it is concluded that the reinedial action objectives have been achieved at the site. The concentrations of site-related contaminants remaining ki soils are below the levels that allow unrestricted land use. The data review showed that all monitoring wells at both the AST and FPP Areas meet MCLs. There are no further operation and maintenance activities associated with this .site. The PRPs will propaly seal all remaining monitoring wells and discontinue remedy c^imponents, as appropriate. There were no institutional controls implemented for this site and no follow-up activities a.ssociated with the institutional controls. VII. Recommendations and Follow-Up Actions There aie no recommendations and follow-up actions associated with this five-year review. VIII. Protectiveness Statement Remedial action objectives have been achieved so that human health and the environment are protected under all reasonably anticipated site uses and exposures. No further five-year reviews are required by Section 121(c) of CERCLA, EPA regulations or EPA policies. •12- IX. Next Review This is the only five-year review tor the site. Additional five-year reviews are not necessary since the remedi^ion allows for unlimited use and unrestricted exposure. / / Appridved;^ ., Walter E. Mugdan, Director Date Emergency and Remedial Response Division -13- Table 1: Chronology of Site Events Event EPA and Island Chemical Corp. conduct preliminary site investigations. EPA conducts removal action at the site. EPA enters into an AOC with PRPs. VICHEM Site added to the NPL. PRPs conduct RI/FS. SVE system installed and functional at the site. EPA signs the ROD for the site. EPA enters into an "ability to pay" Consent Decree with landowner CHS EPA signs Consent Decree with the PRPs to perform RD/RA at the site. PRP pertbiats quarterly groundwater sampling at the AST and FPP areas at the site. Conf!rmator\' soil sampling in the AST Area by PRPs demonstrates that the contaminant levels were below cleimup goals. PRP submits Remedial Action Work Plan. EPA produces Superfijnd Preliminary Close Out Report. PRP performs semi-annual groundwater sampling at the AST and FPP areas at the site.. Post Remediatbn groundwater sampling at the AST and FPP areas at the site demonstrates that contaminant levels are below cleanup goals. Date(s) 1984-1991 1989-1991 1994 1996 1995-2001 2001-2003 2002 2003 2003 2002-2004 20(H 2004 2004 2004-2006 2005-2008 -14- Table 4: Documents, Data, and Information Reviewed in Completing the Five-year Review McLaren Hart, 1999. Draft Final Treatability Study Workplan, Virgin Island Chemical Site, May 1999. Golder Associates Inc. 2000. Revised Final Remedial Investigation Report, Volume 1 and Remedial Investigation Addendum, Virgin Island Chemical Site, St. Croix, USVI, submitted to the USEPA October 6, 2000. ^ • Golder Associates Inc. 2001. Feasibility Study Repwrt, Virgin Island Chemical Site, June 20, 2001. ERTEC, 2001. Operations, Maintenance and Monitoring Plan, Soil Vapor Extraction and Air Sparging Systems, VICHEM Site, St. Croix, USVI. February 2001. EPA. 2002. Record of Decision for Virgin Islands Chemical Site, St. Croix, USVI. EPA. August. ^ ^ EPA. 2003a. Consent Decree for Virgin Islands Chemical Site, St. Croix, USVI. EPA. September. EPA. 2003b. Statement of Work for Remedial Action Oversight, Virgin Islands Chemical Site, St. Croix, USVI. December. EPA. 2004. Superfund Preliminary Close Out Report, Island Chemical Corp. Superfimd Site, St. Croix, U.S. Virgin Islands, USEPA Region II, New York, New York, March 24, 2004. Golder Associates Inc. 2004. Remedial Action Report, Virgin Island Chemical Site, September 17,2004. Golder As.sociates Inc. 2008. Final Post Remediation Monitoring Report, Virgin Island Chemical Site, April 28, 2008. . EPA guidance for conducting five-year reviews and other guidance and regulations to determine if any new appUcable or relevant and appropriate requirements relating to the protectiveness of the remedy have been developed since EPA issued the ROD. -15- Table 7: Acronyms Used In this Document AOC AST CERCLA CHS CHS, Inc. COC EPA FFS 1 FPP FS MCL •u&^kg f^a/i \ MNA NPL 0«&M OSWER RA RAWP RD RI RI/FS RAO ROD RPM SVE/AS TCE Administrative Order on Consent Above Ground Storage Task Comprehensive Environmental Response Compensation, and Liability Act CHS Holding Corporation Charles H. Steffey, Inc. Contamiriation of Concern United States Environmental Protection Agency Focused Feasibility Study Former Process Pit Feasibility Study Maximum Contaminant Level Micrograms per Kilogram Micrograms per Liter Monitored Natural Attenuation National Priorities List Operation and Maintenance Office of Solid Waste and Emergency Response Remedial Action Remalial Action Work Plan Remedial Design Remedial Investigation Remedial Investigation/Feasibility Study Remedial Action Objectives Record of Decision Remedial Project Manager Soil Vapor Extractioa'Air Sparging trichloroethylene -16- Table 7: Aeronyms Used in this Document TEX VICHEM VIDPNR VOCs Total toluene, ethylbenzene & xylene Island Chemical Corp./Virgin Island Chemical Corp. Virgin Islands Department of Planning and Natural Resources Volatile Organic Compounds 17-