SITE INFORMATION AND CORRESPONDENCE FILE 1

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Chevron ;; Chevron Chevron USA Products Compury MAY 1 (�< y' 6001 Bollinger Canyon Rd., Bldg. L P.O. Box 5004 /r{�N 1995 San Ramon, CA 945MB04 /TMS�Ty's Site Assessment 00 Remediation Group May 16, 1995 W. Michael Infurna San Joaquin County Environmental Health P.O. Box 2009 Stockton, CA 95201 Re: Former Chevron Station #9-4054,2103 Country Club Blvd., Stockton. CA Attached Drilling Report(Terra Vac,4/3/95) Attached Dual Vapor Extraction Test (Terra Vac,4/12/95) Dear Mr. Infurna: Attached you will find a drilling report dated April 3, 1995, which was prepared by Chevron's consultant,Terra Vac Corporation (Terra Vac) to describe the results of an additional subsurface investigation performed at and near the subject site on March 16, 1995. As part of their subsurface investigation Terra Vac drilled two soil borings, collected soil samples, and installed groundwater monitoring wells in each. Soil samples from each boring were analyzed for the presence of TPHGas and BTF.X constituents. Petroleum hydrocarbons were detected at boring location MW-8 which is located on the south side of the subject property. There were no petroleum hydrocarbons detected at boring MW-9 which was located offsite, northeast of the property. Both wells will be included in the ongoing groundwater monitoring program. Chevron's consultant, Blaine Tech Services will monitor each well for the presence of phase separated hydrocarbons and gauge depth to water before development and sampling occurs. Subsequent results will be conveyed in Blaine's quarterly monitoring report for the second quarter of this year. The purpose of Terra Vac's investigation was to provide additional definition to soil and groundwater contamination at the subject site. In evaluating the data obtained by Terra Vac, it is reasonable to infer that soil contamination does not extend much beyond well MW-8. As a result, lateral and vertical definition of soil contamination to the south has been achieved. Similarly, results obtained at well MW-9 completely define the extent of soil contamination in the downgradient direction. The subsequent groundwater results from both wells should provide further definition to the extent of groundwater contamination. Additional definition of soil contamination onsite will be obtained during the implementation of Tetra Vac's proposed Remediation Work Plan (Terra Vac, 10/20/94).The data obtained during their , proposed well installations will aid in the optimal design of the remediation system.