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. •1 s <br /> Mr Martin Harns <br /> Apnl 18, 2001 <br /> Page 2 of 6 <br /> 1.3 Subsurface Investigation <br /> As required by PHS/EHD, Ground Zero supervised the drilling of three soil borings on December <br /> 17, 1999 to investigate the extent of soil and groundwater contamination in the vicinity of the <br /> former UST Groundwater was initially encountered at a depth of approximately 9 5 feet below <br /> ground surface (bgs) during drilling Results of the investigation indicated that soil and <br /> groundwater had been impacted by an unauthorized release of gasoline from the former UST <br /> Analytical results of soil samples collected at the site are summarized in Table 1 Analytical <br /> results of groundwater samples are summarized in Table 2 <br /> 2.0 PROCEDURES <br /> 2.1 Permitting <br /> Prior to initiating fieldwork, well installation permits were obtained from San Joaquin County <br /> PHS/EHD All fieldwork was performed in accordance with the Ground Zero's Site Safety Plan and <br /> Quality Assurance/Quality Control Plan <br /> 2.2 Drilling and Soil Sampling <br /> On January 22, 2001, V&W Drilling (V&W), a State-licensed drilling company (C57-720904), <br /> advanced four soil bonngs/groundwater monitoring wells (MWl, MW2, MW3 and MW4) to further <br /> investigate the extent of subsurface contarrunation Boring and well locations are shown on Figure 2 <br /> All work was conducted under the supervision of field geologist Sean Garvey and project manager <br /> John Lane, a California Registered Geologist Ms Lori Duncan of PHS/EHD conducted the <br /> grout inspection and observed field activities <br /> A drilling rig equipped with hollow stern augers was used to advance the borings Soil samples <br /> were collected at 5-foot intervals using an 18-inch long core sampler lined with new 2-inch <br /> diameter brass sleeves, which afforded soil identification and subjective evaluation for <br /> contamination A flame ionization detector (FID) was used to monitor the presence of volatile <br /> organic compounds in the soil Soil samples selected for analysis, based on field observations and <br /> PID readings, were sealed, labeled, and immediately placed in an iced cooler for transportation <br /> under chain of custody protocol to Argon Laboratory (Argon), a State certified testing laboratory <br /> (ELAP 2359) Analysis consisted of total petroleum hydrocarbons as gasoline (TPHg) using modified <br /> EPA method 8015, and benzene, toluene, ethylbenzene, xylenes (BTEX), and Methyl tert butyl ether <br /> (MTBE) using EPA method 8020 All drilling and sampling equipment was decontaminated prior to <br /> use and between sample collection events to minimize the possibility of cross contamination <br /> Soil generated during drilling activities was placed on and covered with plastic sheeting Rinsate <br /> . generated during drilling activities was placed into DOT approved 55-gallon drums Both waste <br /> streams are currently stored on site pending characterization for proper disposal <br /> G 1Dati\CROUNDZE\Tu13Boy1ReportslWELLRPT doe <br />