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Groundwater Investigation,Monitor Well Destruction and Installation,and Interim Remediation PumP Test Report
<br /> noyett Petroleum,419 S.Main St.,Manteca,CA
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<br /> January 30,2004
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<br /> depth intervals of 4-6 feet, 9-11 feet, and 16 feet. One groundwater sample was collected from each
<br /> ' boring from a depth of 18 feet for laboratory analyses.
<br /> On August 27 and 30, 1999, WHF completed four soil borings. The borings, which varied in total depth
<br /> frons 26.5 to 36.5 feet bgs, were subsequently converted into monitoring wells MW-1 through MW-4.
<br /> ' Laboratory analytical results of eleven soil samples collected from the borings indicated no detectable
<br /> Concentrations of petroleum hydrocarbons with the exception of MTBE, which was detected in soil
<br /> samples from the borings for MW-1, MW-3, and MW-4. MTBE was detected in groundwater samples
<br /> ' coIlected from MW-1, MW-3, and MW-4, tertiary-butanol (TBA) was detected in the sample collected
<br /> from MW-1, and tertiary-amyl methyl ether (TAME) was detected in the samples collected from MW-1
<br /> and MW-3. Quarterly groundwater monitoring at the site began in the fourth quarter of 1999.
<br /> ' From December 20 through 22, 2000, WHF completed four soil borings that varied in total depth from
<br /> approximately 20 to 25 feet bgs. The borings were subsequently converted into monitoring wells MW-5
<br /> through MW-8. Laboratory analytical results of twelve soil samples collected from the borings indicated
<br /> petroleum hydrocarbons were not detected at or above the laboratory reported detection liinits in any of
<br /> the samples.
<br /> ' On February 2, 200I, WHF advanced two CPT borings at the site. CPT-1 and CPT-2 were completed to
<br /> depths of 76 and 76.4 feet bgs, respectively. Both borings were terminated due to refusal. Beds of clay
<br /> ' were encountered in CPT-1 at depths of 20 to 24.1 feet and 50.2 to 57.6 feet bgs. In CPT-2, beds of clay
<br /> were encountered at depths of 23.8 to 26.4 feet, 49.7 to 56.4 feet, and 62.7 to 66.9 feet bgs.
<br /> iOn April 25, 2001, WHF installed a deep monitoring well, MW-9, to a depth of 50.5 feet bgs. The
<br /> ' screened interval for the well was installed at approximately 40.5 to 50.5 feet bgs. Two soil samples were
<br /> collected from the borehole at depths of 43.5 feet and 50 feet for laboratory analyses. BTEX, TPH-G, and
<br /> MTBE were not detected at or above the laboratory reported detection limits in the soil samples collected
<br /> from the borehole. Laboratory analytical results of a groundwater sample collected from MW-9 indicated
<br /> that none of the analytes of concern (BTEX, TPH-G, and selected gasoline oxygenates/additives) were
<br /> detected, with the exception of MTBE, which was detected at a concentration of 14 micrograms per liter
<br /> On September 26, 2002, a representative of Condor was onsite to measure water levels and collect
<br />' groundwater samples at monitoring wells MW-1 through MW-9 for the third quarter 2002 groundwater
<br /> monitoring event. Monitoring wells MW-4, MW-5, and MW-6 were heavily silted, and MW--4 and MW-5
<br /> were dry. Mr. Wong was onsite to observe a portion of the field activities.
<br /> At the request of the SJCEHD, a Condor representative was onsite to redevelop monitoring wells MW-4,
<br /> MW-5, and MW-6 on September 27, 2002. The redevelopment activities failed to significantly reduce the
<br /> amount of sediment inside the well casings of MW-4 and MW-5. MW-6 was successfully redeveloped by
<br />' removing a significant amount of the sediment from inside the well casing. A groundwater sample was
<br /> collected for laboratory analyses from MW-6 on September 30, 2002. Condor has conducted quarterly
<br /> groundwater monitoring activities at the site since the third quarter of 2002.
<br /> On November 20, 2002, Condor conducted a sensitive receptor survey (SRS) within a 2,000-foot radius
<br /> of the site to identify potential areas of groundwater recharge or discharge, schools, and potential water
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<br /> included the identification of a municipal well located approximately 1,500 feet west of the site. A
<br /> detailed description of the SRS was presented in Condor's Groundwater Monitoring Report, Third
<br />' Quarter 2002, dated January 16, 2003.
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<br /> �� CONDOR
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