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S <br /> �... V-/ <br /> San Joaquin County <br /> Pp U I N <br /> Environmental Health Department DIRECTOR <br /> Donna Heran, REHS <br /> 1868 East Hazelton Avenue <br /> Stockton, California 95205-6232 PROGRAM COORDINATORS <br /> Robert McClellon, REHS <br /> w. Jeff Carruesco,REHS, RDI <br /> rFoley,RENS <br /> FoRac Website: www.sjgov.org/ehd Linda <br /> Turkatte,RENS <br /> Phone: (209)468-3420 <br /> Fax: (209)464-0`138 <br /> July 8, 2014 <br /> Jon Armstrong Albert Scannavino <br /> BP West Coast Products LLC Scannavino Properties <br /> 501 Westlake Park Boulevard 5463 Cherokee Lane <br /> Houston, TX 77079 Stockton, CA 95215 <br /> Subject: former ARCO Station #595 <br /> 6100 North Highway 99 <br /> Stockton, California 95212 <br /> The San Joaquin County Environmental Health Department (EHD) has received and <br /> reviewed Soil Vapor Extraction Well Installation & Pilot Test Report (Pilot Test Report) dated <br /> 13 March 2014, prepared and submitted by your consulting firm, Arcadis, on your behalf for <br /> the above-referenced site. The report was submitted in accordance with the EHD's <br /> approval letter dated 16 July 2012 for Soil Vapor Extraction (SVE) Pilot Test Work Plan. <br /> In Pilot Test Report, Arcadis reported on the installation and testing of two soil vapor <br /> extraction wells screened from 54 to 69 feet below surface grade (bsg), below the most <br /> intensely impacted soil generally occurring between near surface grade to approximately 25 <br /> feet bsg, locally to 40 feet (bsg). The contaminant mass recovery rates during the SVE pilot <br /> test were approximately 69 pounds/day and 109 pounds/day of TPH for the two SVE wells <br /> tested; a seemingly high recovery rate for extraction wells not screened in the most <br /> intensely impacted interval. In SVE Report, Arcadis recommends further evaluation of <br /> options for the site, including possible closure, and states that a report with <br /> recommendations will be issued. <br /> The EHD has evaluated your site for possible closure under the recently adopted Low-threat <br /> Underground Storage Tank Closure Policy (LTCP), and although the dissolved plume is <br /> relatively small and dissolved benzene and methyl tert-butyl ether (MTBE) concentrations <br /> less than those identified as not posing a significant threat in the LTCP, your site cannot be <br /> closed under the LTCP due to lack of public water service in the area, the close proximity of <br /> water supply wells, the unresolved potential vapor intrusion problem, and benzene and <br /> ethylbenzene concentrations in shallow soil exceeding those acceptable in the LTCP for <br /> direct contact and exposure to outdoor air. Therefore, to be closed at this time, your site <br /> must qualify for closure under the California State Water Resources Control Board <br /> (SWRCB) Resolution 92-49 or under the guidelines of Appendix A of the Tri-Regional Board <br /> Staff Recommendations for Preliminary Investigation and Evaluation of Underground Tank <br /> Sites issued by the Central Valley Regional Water Quality Control Board (CVRWQCB). <br /> Whether or not Arcadis recommends case closure, these items should be addressed in the <br /> report of recommendations in Arcadis indicated to be in preparation; please include an <br /> estimate of the residual sorbed contaminant mass, a fate and transport model for potential <br />