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<br /> `Site Assessment Work Plan
<br /> 1022 Frontage Road,Ripon, California
<br /> CONESTOGA-ROVERS March 7, 2008
<br /> &ASSOCIATES
<br /> June 2002: In June 2002, AGE conducted a 48-hour groundwater extraction pilot test to assess the
<br /> characteristics of the aquifer and its response to groundwater extraction. The test was performed on
<br /> extraction well EW-1 screened from 16 to 36 ft bgs.A maximum drawdown of 9.76 feet was measured in
<br /> extraction well EW-1 while pumping at a constant rate of 6 gallons per minute (gpm). A maximum G
<br /> drawdown of 0.40 feet was observed in observation MW-1, located 20 feet from extraction well EW-1. U S
<br /> The transmissive and hydraulic conductive of the shallow aquifer were calculated at 1,000 ftz/da and f
<br /> tY Y h' q Y
<br /> 0.175 cm/sec,respectively. Additional details are presented in AGE's November 6,2002 Well Installation
<br /> and Groundwater Aquifer Pumping Test Report.
<br /> May 2004: In May 2004, TEC Accutite removed one 1,000-gallon, steel waste oil UST. Soil samples
<br /> TPI and TP2 were collected by CRA during the waste oil UST removal activities. No TPHg,benzene,
<br /> fuel oxygenates,volatile organic compounds(VOCs),or poly-chlorinated biphenyls(PCBs)were detected.
<br /> All leaking underground fuel tank (LUFT) metal concentrations appeared to be background
<br /> concentrations. TPHd was detected at concentrations of 4.0 mg/kg (TPI) and 160 mg/kg (TP2). No
<br /> estimate of the amount of soil excavated was provided.
<br /> May 2005:In May 2005,TEC Accutite removed or closed in place the piping related to the former waste
<br /> oil UST. Soil samples WOI through W04 were collected by TEC Accutite during the waste oil piping
<br /> removal activities. No benzene, fuel oxygenates, or PCBs were detected. TPHd was detected in soil N�
<br /> samples WO1, W03, and W04 at concentrations of 3,234,and 17,600 mg/kg,respectively. No VOCs
<br /> were detected, except for 1,3,5-trimethylbenzene(1,3,5-TMB)(2.76 mg/kg), 1,2,4-TMB (1.03 mg/kg),
<br /> and sec-butyl benzene (0.761 mg/kg). No semi-volatile organic compounds (SVOCs) were detected,
<br /> except for naphthalene (2.74 mg/kg) and 2-methylnaphthalene (6.52 mg/kg) in soil sample W04. All '-fid
<br /> LUFT metal concentrations appear to represent background concentrations, except for 392 mg/kg zinc,
<br /> detected in soil sample W03 at 3 ft bgs. No estimate of the amount of soil excavated was provided. 4S
<br /> S
<br /> August 2005:In August 2005,Cambria Environmental Technology Inc. ambria)installed monitoring
<br /> well MW-10 and air sparging well AS-1,and advanced soil boring B-18. Well MW-10 was installed to
<br /> delineate the extent of impacted groundwater west of well MW-9. Well AS-1 was installed to conduct a
<br /> soil vapor extraction/air sparging(SVE/AS) pilot test. Soil boring B-18 was advanced near the former
<br /> USTs to vertically delineate impacted soil and groundwater in the source area. No petroleum
<br /> hydrocarbons were detected in soil samples collected from well MW-10. Elevated petroleum hydrocarbon
<br /> concentrations were detected in the soil sample collected from boring B-18 at 21 ft bgs; however, no
<br /> petroleum hydrocarbons were detected in soil samples collected at 36,46,and 51 ft bgs in boring B-18.
<br /> On August 31,2005,the groundwater sample collected from well MW-10 contained 57 µg/L TPHd and
<br /> 750µg/L MTBE. Hydropunch groundwater samples were collected from boring B-18 at 30,45,and 60 ft
<br /> 5 �-
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