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40 <br /> S E C 0 R <br /> Atlantic Richfield Company <br /> ARCO Service Station 4932 <br /> September 22, 2003 <br /> Page 5 <br /> FINDINGS <br /> Soil Analytical Results <br /> Soil samples were collected from each soil boring at various depth of laboratory analysis TPHg, <br /> MtBE was reported in each of the soil boring at concentrations ranging from 0 0024 mg/kg (EW- <br /> 5,30') to 21 mg/kg (EW-7, 35') TPHg was reported in soil sample EW-5,35 at a concentration of <br /> 0 390 mg/kg TBA was reported in boring SVE-2 at a maximum concentration of 0 380 mg/kg (SVE- <br /> 2, 15) and ethanol was reported in soil samples from borings EW-6 and SVE-2 at a maximum <br /> concentration of 0 380 mg/kg (SVE-2, 15) Soil analytical results are presented in Table 2 The <br /> certified laboratory analytical report and chain-of-custody documentation are presented in Attachment <br /> 4 <br /> Groundwater Analytical Results <br /> TPHg was detected in each of the new extraction wells at concentrations ranging from 3,600 ppb to <br /> and 74,000 MtBE was detected in each of the new extraction wells at concentrations ranging from <br /> 2,700 ppb to and 170,000 ppb Groundwater analytical results are summarized in Table 3 The <br /> certified laboratory analytical report and chain-of-custody documentation are presented in Attachment <br /> 5 <br /> Soil Cuttings <br /> Drilling activities generated approximately 15 cubic yard of soil cuttings that are temporarily stored on <br /> site on plastic sheeting Dillard Environmental, a Calif ornia-certifled disposal contractor, will transport <br /> the stockpiled soil to the Forward Incorporated landfill facility in Manteca, California (Forward) for <br /> disposal <br /> Remedial System Start-up <br /> Remedial system installation at the site was initiated in January 2003 Installation of underground <br /> conveyance piping including groundwater extraction and soil vapor extraction piping, electrical <br /> conduit, well head connections to all onsite remedial wells, and remedial equipment was completed <br /> by March 2003 Pacific Gas and Electric completed the installation of natural gas in May 2003 <br /> Remedial system start-up and shake down was completed in May 2003 with official remedial start-up <br /> on June 14, 2003 <br /> The remedial system currently consists of a soil vapor extraction (SVE) system and groundwater q <br /> extraction system (GWE) The SVE system consists of a Thermtech Vac 50 thermal oxidizer <br /> connected to wells SVE-1, SVE-2, MW-1, MW-2, MW-4, and EW-1 The groundwater extraction , <br /> system consists of submersible extraction pumps in wells EW-1 and EW-6 connected to an air <br /> stripper and three 2000 lbs granular activated carbon vessels prior to discharge to the City of <br /> Stockton sanitary sewer Discharge of groundwater to the sanitary sewer is permit through the City of <br /> Stockton Municipal Utilities Department and permit to operate the thermal oxidizer was issued by San <br /> Joaquin Valley Air Pollution Control District 2 <br /> To date the soil vapor extraction system has removed 10,239 pounds (lbs) of TPHg, 131 lbs of ' <br /> benzene 3,044 lbs of MtBE The groundwater extraction system has pumped 46,800 gallons of water <br /> at an average pumping rate of 1 1 gpm To date the groundwater extraction system has removed 43 <br /> lbs of TPHg, 1 3 lbs of benzene, and 56 lbs of MtBE Soil vapor and groundwater extraction system <br /> performance data is included in Tables 5 and 6 Future quarterly remedial summaries will be <br /> included with the groundwater monitoring report <br /> 11ARC0149321Reportslremedia1 well-start up doc <br />