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Site Background ---
<br /> Raymond Investment Corporation-Stockton,CA
<br /> Page 2
<br /> groundwater in the vicinity of the former UST location Condor described the results of the investigation
<br /> in the Soil and Groundwater Investigation Report, dated June 1, 2004 In the report, Condor
<br /> recommended preparing a work plan for the installation of three groundwater monitoring wells and
<br /> initiating quarterly groundwater monitoring at the Site In a letter dated July 7, 2004, Victoria McCartney
<br /> of the SJCEHD directed the preparation and submittal of a work plan for the installation of three
<br /> groundwater monitoring wells at the Site Condor prepared the Monitoring Well Installation Work Plan,
<br /> dated August 11, 2004, at the request of Beverly Garcia in response to that directive In a letter dated `
<br /> August 25, 2004, Victoria McCartney approved the work plan
<br /> Condor installed three shallow groundwater monitoring wells (MW-1, MW-2, and MW-3) on September
<br /> 23 and 24, 2004 During preliminary well development activities conducted on October 7 and 8, 2004,
<br /> total depth measurements of MW-3 indicated that the lower portion of the well screen was plugged with a
<br /> foreign material (cement grout) Condor prepared the Monitoring Well Installation Preliminary Report
<br /> and Monitoring Well Destruction Work Plan, dated October 12, 2004, that described the installation of
<br /> MW-3 and the discovery of grout inside the well casing In the report Condor recommended that MW-3
<br /> be properly destroyed and a replacement well (MW-3R)be installed approximately ten feet south of MW-
<br /> 3 In a letter dated October 21, 1004, Victoria McCartney of the SJCEHD approved the destruction of
<br /> MW-3 and the installation of MW-3R Monitoring well MW-3 was properly destroyed and MW-3R
<br /> installed on October 26, 2004
<br /> All field and analytical activities involved in the installation, development, and sampling of monitoring
<br /> wells MW-1, MW-2, and MW-3R and the destruction of monitoring well MW-3R are described in
<br /> Condor's Monitoring Well Installation Report, dated December 15, 2004
<br /> On November 8, 2004, a Condor representative was on Site to measure water levels and collect
<br /> groundwater samples from monitoring wells MW-1, MW-2, and MW-3R The average groundwater
<br /> elevation in the monitonng wells was approximately -20 97 feet, the estimated groundwater gradient for
<br /> the Site was calculated to be 0 0054 ft/ft to the northeast Groundwater samples were analyzed for TPH-
<br /> G, TEPH-D, TEPH-MO, and total extractable petroleum hydrocarbons quantified as kerosene (TEPH-K),
<br /> benzene, toluene, ethyl benzene, total xylenes (BTEX), and gasoline oxygenates/additives The gasoline
<br /> oxygenates/additives include methanol, ethanol, tertiary-butanol (TBA), methyl tertiary-butyl ether
<br /> (MTBE), di-isopropyl ether (DIPE), ethyl tertiary-butyl ether (ETBE), tertiary-amyl methyl ether
<br /> (TAME), 1,2-dichloroethane(1,2-DCA), and EDB No petroleum hydrocarbons were detected at or above
<br /> the laboratory reported detection limits in the groundwater samples collected from monitonng wells MW-
<br /> 1, MW-2, and MW-3R during the November 8, 2004 groundwater monitonng event
<br /> On February 4, 2005, a Condor representative was on Site to measure water levels and collect
<br /> groundwater samples from monitonng wells MW-1, MW-2, and MW-3R The average groundwater
<br /> elevation in the monitonng wells was -20 19 feet, the estimated groundwater gradient for the Site was
<br /> calculated to be 0 0053 ft/ft to the northeast Groundwater samples were analyzed for TPH-G, TEPH-D,
<br /> TEPH-MO, and TEPH-K, BTEX, and gasoline oxygenates/additives (methanol, ethanol, TBA, MTBE,
<br /> DIPE, ETBE, TAME, 1,2-DCA, and EDB) No petroleum hydrocarbons were detected at or above the
<br /> laboratory reported detection limits in the groundwater samples collected from monitoring wells MW-1,
<br /> MW-2, and MW-3R during the February 4, 2005 groundwater monitoring event
<br /> On May 4, 2005, a Condor representative was on Site to measure water levels and collect groundwater
<br /> samples from monitoring wells MW-1, MW-2, and MW-3R The average groundwater elevation in the
<br /> monitoring wells was -18 49 feet, the estimated groundwater gradient for the Site was calculated to be
<br /> 0 0049 ft/ft to the east Groundwater samples were analyzed for TPH-G, TEPH-D, TEPH-MO, and
<br /> f• TEPH-K, BTEX, and gasoline oxygenates/additives (methanol, ethanol, TBA, MTBE, DIPE, ETBE,
<br />
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