SITE INFORMATION AND CORRESPONDENCE FILE 2

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i ENVIRONMENTAL HEALTH DEPARTMENT SAN JOAQUIN COUNTY 2' 'Z Donna K. Heran, R.E.H.S. Unit Supervisors 304 East Weber Avenue, Third Floor Carl Borgman, R.E.H.S. Director g� Mike Huggins, R.E.H.S., R.D.I. AI Olsen, R.E.H.S. Stockton, California 95202-2708 • cyClFORN�P. Program Manager Telephone: (209) 468-3420 Douglas W. Wilson, R.E.H.S, LaurieA. Cotulla, R.E.H.S. Margaret Lagorio, R.E.H.S. Program Manager Fax : (209) 464-0138 Robert McClellon, R.E.H.S. Mark Barcellos, R.E.H.S. RODGER LISTON DEC p 3 2002 DARPETRO INC USA SERVICE STATION 3450 EL CAMINO CERES CA 95307 RE: DARPETRO, INC Site Code: 1060 749 E CHARTER WAY STOCKTON, CA 95206 San Joaquin County Environmental Health Department (EHD ) received Work Plan (WP), prepared by California Geophysical Group , Inc. (CGG ) on your behalf, on 16 October 2002 and has reviewed the WP. The undirected WP lists the historical stages of the site investigation , references the reports containing the results of the various investigations , and proposes to advance 7 soil gas test borings to 23 feet below surface grade (bsg) to collect soil gas samples for laboratory analysis to determine the source of the hydrocarbon contamination . EHD notes that at this time you have been directed by letter dated 11 June 2001 to : • Prepare geological cross sections of your site; • Delineate impacted soil and ground water south of VW-5; and • Delineate the vertical extent of impacted ground water. These issues still need to be addressed . Also, at the 19 June 2002 meeting attended by you , your consultant and EHD personnel , CGG proposed installing ground water monitoring wells west of the dispenser islands to further ! characterize the site and test CGG's hypothesis that significant contamination may be migrating onto your site from an off-site source. While the proposed soil vapor survey does not address any of these issues, it may have merit, but the WP does not contain enough information for EHD to properly evaluate the proposed scope of work at this time . The WP should be revised , address the issues noted above , and include the following information : • Geological cross sections; • A site map with the proposed boring localities , former and existing USTs, dispenser islands and product lines and other pertinent information — extraneous data should not be shown on the site plan , overprints should be eliminated and all labels should be clearly legible; • A rational or justification for the sampling points selected ; 'I