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' JUL I 0 ^995 r John R. Coon, Esq. Coon, Sanford & Amerling, P.C. P.O. Box25918 Chandler's Wharf, Suite 202 Gallows Bay, St. Croix USVI 00824 Re: EPA's Responses to Western Auto Comments on the Draft FS and Final; Phase II Rl Dear Mr. Coon: This letter is in response to your consultant, ENSR comments on the draft FS and Final Phase II Rl dated April 17, 1995 and April 27, 1995 for the Tutu Wells Site. 1) Issuance of the FS without finalization of the Rl may be premature. Response: The Rl has now been finalized. 2) There is a lack of correlation between the information and analyses in the Risk Assessment and the conclusions drawn in the FS, i.e., the FS identifies compounds exceeding NYS TAGM levels in soil, but which are not chemicals of potential f *"' concern for groundwater. Response: The Baseline Risk assessment conducted by EPA presented an evaluation of the potential risks and hazards to human health and the environments that may exist at the Tutu Wells Site currently and in the future in the absence of any remediation. When the Baseline Risk Assessment was completed in October 1994, there was no direct contact risk of contaminated soil, but there was an indirect risk of contaminated soil leaching into the aquifer acting an a continuous sources of contamination. EPA provided the TEIC group with the TAGMs as interim cleanup goals while EPA determined site- specific soil cleanup goals. We have completed the Estimation of Soil Cleanup Levels Required to Protect Groundwater As a Source of Drinking Water report. We have requested the TEIC group to use these goals instead. r SYMBOL —— > SURNAME --£, 'ATE ——/-> ENYCSI1 C. KWAN / // *65047* 65047 3) Soil cleanup values should be based on a site-specific risk assessment. Response: Since the human health risk assessment determined their was no significant ris* from direct contact to soils (with the exception of the one PCB area at Tillett), the need for soils clean up is being determined by the migration-to-groundwater pathway. EPA will not require clean up of soils that are not contributing to the groundwater problem. The revised FS will use soil cleanup numbers for BTEX and chlorinated VOCs determined by vadose zone modeling. 4) Soil quality behind Western Auto is improperly characterized. Response: We have requested TEIC to correct misstatements of fact in the FS and should rewrite the paragraph on page 2-17 to clarify what the actual soil conditions are. EPA has given Western Auto attachment of reported errors which TEIC will verify and change where necessary. The contaminated gravel layer and the ruptured 4-inch PVC pipe will be discussed, regardless of who "owns" the property. 5) Results of the Gore Sorber study are not included in the FS, though the results are critical to identification of source(s) of petroleum hydrocarbons encountered behind Western Auto. Response: The Gore-Sorber study was referenced and discussed somewhat more thoroughly in the RI. A complete reiteration is not needed in the FS. However, the fact that the Gore-Sorber study indicates releases of petroleum constituents (apparently diesel fuel) beneath Four Winds Plaza should be discussed and that these anomalies may correlate with the same ruptured 4-inch PVC pipe, which was traced northward under the building. EPA recommends a source control action be performed to assure the pipe is no longer leaking into the gravel behind Western Auto. Downgradient groundwater monitoring should be performed in the future to confirm that these constituents are not impacting groundwater. 6) The FS does not consider information in the Western Auto Tank Closure Report that demonstrates the source of the contamination behind Western Auto. Response: This information should be considered in assigning liability. However, regardless of the "owner", the contaminated gravels and leaking pipe behind Western Auto should be addressed by the FS as areas potentially impacting groundwater. 7) Western Auto agrees there is a gravel layer with perched water overlying a clay. Response: None necessary. 8) Western Auto should not be considered a PRP for the groundwater contamination. Response: Western Auto has a documented release to soils from the leaking tank, now removed. DPNR may require additional confirmatory sampling to prove the area is clean. 9) The preferred remedial alternatives presented in the FS require Western Auto to excavate and dispose of soil which has already been removed from the site. Response: The FS should indicate how the soil volume to be remediated was determined and should take into account the removal action already completed. Note that additional sampling might be required to assure EPA and DPNR that all contaminated soils were removed from the tank graves. Previous sampling showed only analysis of total petroleum hydrocarbons. 10) The extent of the proposed excavation area and volume for Western Auto in Table 4-1 is not explained or justified. Response: If information was provided to the TEIC group, the FS should clearly explain how affected areas and depths were obtained for all sites. 11) The FS employs an inconsistent use of the IRM concept. Response: Information concerning all completed or proposed removal actions performed supplementally to the FS should be incorporated into the FS. The revised FS will determine areas requiring remediation based on site-specific soil clean-up levels that will be protective of groundwater based on fate-and-transport modeling. 12) The discussion on contamination at individual PRP sites is inconsistent. Response: EPA requested in our FS comments to the TEIC group that the text should be clarified to distinguish between product and soil sample results. 13) Western Auto agrees that it has no soils impacted with chlorinated VOCs that require remediation. Response: None necessary. TUT OO8 O586 14) No documentation is provided for the elimination of soil remediation alternative SRA 2. Response: The revised FS will include the preliminary screening as a section in the report. Comments on the Phase II RI Dated 4/27/95 These comments concern the Phase II RI which has been finalized. They refer mainly to the results of the Gore-Sorber soil gas study and the samples associated with the ruptured pipe. Response: The RI will not be further revised at this point. The Gore Sorber surveys indicate potential releases of hydrocarbons (principally diesel constituents) beneath the Four Winds Shopping Center. Remediation of the oil-saturated gravels around the ruptured pipe should be evaluated in the FS. Regardless of who is liable, this source should be controlled, or it could eventually impact groundwater. With respect to the soil gas anomalies beneath Four Winds, EPA believes they indicate releases of petroleum hydrocarbons to soils, quite possibly from the 4-inch PVC pipe. A "sentinel" groundwater monitoring immediately downgradient of the building is recommended. Thank you for your input. Sincerely yours, Caroline Kwan Project Manager New York/Caribbean Superfund Branch II cc: Andrew Praschak- CFO TUT 008 0587