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U <br /> C A M B R I A <br /> (MTBE) were detected by EPA Method 8260 during the first and second quarters of 2000, but <br /> none has been detected since. No petroleum hydrocarbons or MTBE have been detected in wells <br /> MW-6 or MW-8. These results suggest that petroleum constituents have not impacted the <br /> groundwater beneath the site. <br /> Previous soil investigations have demonstrated that the residual petroleum hydrocarbons and <br /> MTBE in soil are limited to the northwestern dispenser area. This area was over-excavated <br /> following UST,dispenser, and piping removals in February 1999, and the impact is delineated by <br /> borings SB-1, SB-3 through SB-5, and SB-9 (boring locations shown on Figure 2). <br /> Further excavation may not be possible due to the canopy and dispenser facilities and is not <br /> economically feasible at this time. Therefore, Cambria is.proposing soil vapor extraction (SVE) <br /> to remediate the residual petroleum hydrocarbons and MTBE in vadose soil in the northwestern <br /> dispenser island area. <br /> WORK PLAN <br /> Permits: Cambria will obtain any necessary permits from San Joaquin Valley Air Pollution <br /> Control District. As discussed with Harlin Knoll of SJCPHS/EHD, drilling permit No. 00244736 <br /> will be used for this scope of the work, as the work is onsite and Gregg Drilling will be the <br /> contractor. Equilon has obtained an access agreement with the subject site property owners. <br /> Site Safety Plan: Cambria will prepare a Site Safety Plan for field work. <br /> Utility Clearance: Cambria will mark proposed drilling locations and clear the locations through <br /> Underground Service Alert prior to drilling. <br /> Well Installation: Two soil borings (VE-1 and VE-2) are proposed at the locations shown on <br /> Figure 2. These borings will be drilled using hollow-stem auger equipment and will be converted <br /> to soil vapor extraction wells. These wells are placed adjacent to borings MW-5 (SB-2) and SB- <br /> 6, which are located near the presumed source area and contained the highest MTBE <br /> concentrations in soil. <br /> The soil vapor extraction wells will be completed using 4-inch diameter Schedule 40.PVC <br /> casing. The wells will be screened from 15 to 30 fbg. The sandpack will be placed along the <br /> entire screened interval and two feet above the top of the well screen followed by a two-foot <br /> 1346 2 <br />