SITE INFORMATION AND CORRESPONDENCE FILE 1

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California Tank Lines, Inc. Page 2 3105 South EI Dorado Street March 3, 2010 Stockton , California 95206 The EHD does not approve the advancement of the three proposed soil borings along the southern perimeter of this site, the proposed soil boring west of Shop No. 6, or the proposed soil boring directly south of the Wash Rack based on the following : • Data submitted in reports from 2008 through 2009 indicate that groundwater flow direction is generally toward the southeast and northeast relative to monitoring well MW-1 where two diesel underground storage tanks (USTs) were removed in September 1998 . Since monitoring well MW-3 is down-gradient of MW-1 and groundwater analytical results for MW-3 have been non-detect for chemicals of concern for at least one year, the EHD does not believe soil borings are necessary south of MW-3. Furthermore, during the installation of MW-3 , analytical results for soil samples collected at fifteen , thirty, and fifty feet bsg were non-detect for chemicals of concern while only low concentrations of toluene [0.007 milligrams per kilogram (mg/kg)] and total xylenes (0. 0076 mg/kg) were detected in soil samples collected at thirty-five feet bsg . • CPT boring P-3 was advanced approximately thirty-five feet southwest of MW- 1 in October 2007. Analytical results for grab groundwater samples collected at thirty-five, fifty-five , and ninety-six feet bsg from P-3 were non-detect for chemicals of concern . Based on these groundwater analytical results, the EHD does not believe additional soil borings are necessary south and southwest of MWA . • Proposed soil borings west of Shop No. 6 and south of the Wash Rack are both up- gradient of the source areas and the EHD believes these two proposed borings are too far removed from the former USTs to warrant additional investigation . Grab groundwater samples collected in October 2007 from CPT boring PA , approximately thirty-five feet west of monitoring well MW-2 where two USTs were removed , were non- detect for chemicals of concern at sixty, ninety, and one-hundred-twenty-five feet bsg . Also soil boring B-4, advanced northwest of MW-2 in November 1996 , had non-detect results for soil samples collected at ten , twenty, and thirty feet bsg , and low concentrations of benzene and TPH-g in the one grab groundwater sample collected from B-4. Based on these analytical results, the EHD does not believe it is necessary to collect additional soil and groundwater samples west and northwest of MW-2. Please submit an encroachment permit issued by the City of Stockton for the advancement of the three proposed borings in the City right-of--way on the west side of EI Dorado Street, along with a boring permit application and permit/inspection fee of $434 to the EHD and complete the fieldwork by May 14, 2010. Notify the EHD at least a week prior to the scheduled fieldwork. By letter dated January 12, 2009 , the EHD directed that a sensitive receptor survey report be submitted by March 4 , 2009 , and a corrective action plan (CAP) that included several methods for site remediation be submitted by April 6 , 2009 . The EHD also requested contaminant mass estimates , supported by calculations, for sorbed and dissolved TPH-g, benzene, TPH-d and TPH-mo. To date, the EHD has not received any of these items . Also, Site Investigation Results and Site Conceptual Model, dated September 30 , 2008, has not been uploaded to GeoTracker. Complete the above directives by April 15 , 2010. Prior to unloading Soil Vapor Survey Report, Human Health Risk Assessment, and Additional Site Investigation Work Plan,