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rte, <br /> TPH-G, toluene, ethylbenzene and total xylenes were detected at concentrations of 150,000, 180, <br /> 1,800 and 5,500 µg/kg respectively in a soil sample from boring GP-1 at 15 to 15.5 feet bgs. All soil <br /> samples were analyzed for methyl tertiarybutyl ether (MTBE) with to detections above laboratory <br /> detection limits (see Table 1 and Figure 3). <br /> 4 <br /> Petroleum hydrocarbons were detected in three of the four groundwater samples collected. The <br /> highest concentrations of TPH-G, toluene, ethylbenzene and total xylenes were found in GP-4 at <br /> 3,100 µg/kg, 98 µg/kg, 75 µg/kg and 380 µg/kg, respectively. The highest concentration of benzene <br /> �.. was detected in GP-1 at 8.5 µg/kg. All groundwater samples were analyzed for MTBE, di-isopropyl <br /> ether (DIPE), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME) and tertiary <br /> butyl alcohol (TBA) with no detections above laboratory detection limits (see Table 2 and Figure 4). <br /> 3.0 SCOPE OF WORK <br /> +�» 3.1 Pre-Field Activities <br /> Details of.the pre-field activities that were performed in preparation for fieldwork are presented in <br /> �- the Appendix. <br /> f 3.2 Drilling and Soil Sampling Procedures <br /> y Proposed borings B-1 through B-8 will be advanced and sampled with a Geoprobe'�' drill rig and <br /> borings for proposed monitoring wells MW-1 through MW-3 will be advanced and sampled with a <br /> truck-mounted, hollow-stem auger drill rig at the locations shown on Figure 2. Based on the analytical <br /> Y results for samples obtained from the Geoprobe soil borings, two additional well locations,MW-4 and <br /> MW-5 will be selected. Boring locations were selected based on analytical results from the previous <br /> investigation and to better characterize the lateral limits of hydrocarbon-impacted soil at the site (Figure <br /> 2)• <br /> Soil samples will be collected at 5-foot intervals to 25 feet below ground surface (bgs). Grab <br /> groundwater samples will be collected in each of the geoprobe borings once groundwater has been <br /> encountered. All drilling and sampling activities will be performed under an approved site-specific WPI <br /> Health and Safety Plan (HASP) and under the supervision of a WPI project manager and a California <br /> Registered Geologist. <br /> L <br /> Details of the soil and groundwater sampling procedures are presented in the Appendix. <br /> : 3.3 Well Installation, Development and Sampling <br /> t At the completion of drilling and sampling, Monitoring Wells MW-1 through MW-5 will be <br /> ILcompleted as 2-inch-diameter groundwater monitoring wells. Well installation and development will <br /> be conducted under the supervision of a California Registered Geologist in accordance with the <br /> 1160 W. Yosemite Avenue (at Union Road), Manteca, CA 3 <br />