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S C A M B R 1A Mr Jeffrey Wong
<br /> August 26, 2005
<br /> 2002 Aquifer Pump Test During October 2002, Cambria conducted a 5-day groundwater
<br /> extraction (GWE) test Data collected during the test suggest that interim remediation was
<br /> effective Approximately 4,249 gallons of groundwater were extracted over the 5-day period
<br /> Based on the extracted volume and sample analytical results, interim remediation removed
<br /> approximately 3 33 pounds of MTBE Cambria's December 13, 2002 Aquifer Pump Test Report
<br /> summarizes the test activities
<br /> 2003 Well Installation During July 2003, Cambria installed three off-site wells (MW-8, MW-9,
<br /> and MW-10) and one deep on-site well (MW-11) No TPHg, BTEX, or fuel oxygenates were
<br /> detected in soil from well borings MW-8, MW-9, or MW-10, although the samples were analyzed
<br /> outside of hold time Soil samples were not collected from well boring MWA I because it is
<br /> located near MW-1 These results complete lateral definition of petroleum hydrocarbons and fuel
<br /> oxygenates in soil at this site Cambria's December 3, 2003 Site InvestigationlThird Quarter
<br /> Groundwater Monitoring Report and Site Conceptual Model describes this investigation
<br /> 2003 Soil Vapor Extraction (SVE) Test During September 2003, Cambria installed three SVE
<br /> wells (SVE-1, SVE-2, and SVE-3) During October 2003, Cambria performed a 5-day SVE test
<br /> using these wells During this test, approximately 2 68 pounds of TPHg and 142 pounds of
<br /> MTBE were removed Due to low influent concentrations which indicate that there is
<br /> insignificant impact to the source area, Cambria did not recommend additional SVE Cambria's
<br /> November 14, 2003 Soil Vapor Extraction Test Report documents this test
<br /> 2003 Interim GWE events During September, October, and December 2003, Cambria conducted
<br /> three batch GWE events During each event, Cambria extracted groundwater continuously from
<br /> well MW-4 for 5 days During these events, approximately 19,850 gallons of groundwater were
<br /> extracted, removing 8 04 pounds of MTBE Cambria's September 16, 2004 Interim Remediation
<br /> Report/Work Plan/Response Letter presents the interim remediation results
<br /> Groundwater Monitoring Program There are currently eight groundwater monitoring wells on
<br /> site (MW-1 through MW-7 and MW-11), two piezometers (P-I and P-2) on site, and three off-
<br /> site groundwater monitoring wells (MW-8, MW-9, and MW-10), which are gauged and sampled
<br /> quarterly Current depths to water in all wells and piezometers range from 49 to 51 feet below
<br /> grade (fbg) As reported in Cambria's July 6, 2005 Second Quarter 2005 Groundwater
<br /> Monitoring Report, during the second quarter 2005 sampling event, MTBE was detected in wells
<br /> MW-1, MW-3, MW-4, MW-5, MW-7, P-1, and P-2 at concentrations ranging from 24 to
<br /> 1,400 ppb The laboratory noted that the samples from wells MW-7 and P-1 were analyzed
<br /> outside the EPA recommended hold time TBA was detected in wells MWA through MW-4,
<br /> MW-7, P-1, and P-2 at concentrations ranging from 29 to 96,000 ppb The laboratory noted that
<br /> the samples from wells MW-7 and P-1 were analyzed outside the EPA recommended hold time,
<br /> and the result for P-1 (96,000 ppb) is an estimated value because the concentration exceeded the
<br /> calibration of the analysis Well MW-7 also contained 2 4 ppb TAME, and piezometer P-1
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