ARCHIVED REPORTS XR0009018 - Laserfiche WebLink

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CAMBRIA These results delineate fuel oxygenates in soil north of the USTs and to the east and southeast of the site The findings of this investigation are documented in Cambria's December 13, 2002 Response Letter/Site Investigation and Third Quarter 2002 Groundwater Monitoring Report/Work Plan 2002 Aquifer Pump Test During October 2002, Cambria performed an extended aquifer pump test extracting 4,248 5 gallons of groundwater from MW4 over a five day period Based on the extracted volume and sample analytical results, approximately 3 33 pounds of MTBE were removed Complete results from the aquifer pump test are documented in Cambria's December 13, 2002 Aquifer Pump Test Report 2003 Soil Vapor Extraction (SVE) Test During September 2003, Cambria installed three SVE wells (SVE-1, SVE-2, and SVE-3) During October 2003, Cambria performed a five-day SVE test using these wells During this test, approximately 2 68 pounds of TPHg and 142 pounds of MTBE were removed Due to low influent concentrations, which indicate that there is insignificant impact to the source area, Cambria does not recommend additional SVE Cambria documents this test in our November 14, 2003 Sod Vapor Extraction Test Report Groundwater Monitoring Program Prior to this investigation, there were seven monitoring wells located onsite (MW-1 through MW-7) and two piezometers (P-1 and P-2), which are sampled quarterly During the second quarter 2003 sampling event, MTBE was detected in wells MW-1 through MW-5, MW-7, P-1, and P-2 at concentrations ranging from 1 8 to 280,000 ppb TBA was detected in wells MW-1 through MW4, MW-7,P-1, and P-2 at concentrations ranging from 190 to 74,000 ppb No other fuel oxygenates were detected During the same event, TPHg and BTEX were also not detected, although some reporting limits were elevated Based on the analytical results from the CPT borings and groundwater monitoring program, SJCEHD requested submittal of a work plan for further assessment of the lateral and vertical extent of gasoline constituents in groundwater beneath the site Cambria submitted work plans on June 5, 2002 and December 13, 2002 As noted above, Cambria installed some of the proposed wells (MW4 through MW-7) during September 2002 and submitted a report summarizing the investigation in December 2002 The results of the remaining lateral and vertical assessment activities are presented below 0955 4