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Appendix B:Previous Environmental Investigations <br /> VERNALIS OFFSITE <br /> SAIC 2008 Site Investigation 12 <br /> SAIC advanced seven soil borings (SB-26 through SB-29, and SB-31 through SB-33) on <br /> February 25 through 27, 2008, to assess the extent of crude-oil affected soil and groundwater. <br /> The borings were advanced to depths ranging from 40 to 44 feet bgs, and soil and groundwater <br /> samples were collected. Soil samples were analyzed for TPHc, BTEX, and PAHs. Groundwater <br /> samples were analyzed for TPHd, BTEX, and PAHs. Select groundwater samples were also <br /> analyzed for General Minerals and total dissolved solids (TDS). <br /> No exceedances of the COPCs were detected in the soil samples; however, COPCs were detected <br /> in four of the seven groundwater samples collected. TPHd concentrations above the WQOs <br /> ranged from 160 µg/L (SB-26) to 240 µg/L (SB-33). One or more PAHs were detected in <br /> groundwater above the WQO and ESL in three of seven borings. BTEX were not detected in <br /> groundwater. The TDS concentrations ranged from 888 milligrams per liter(mg/L) to <br /> 1,390 mg/L, and did not exceed the TDS WQO of 3,000 mg/L. <br /> SAIC 2008 Monitoring Well Destruction13 <br /> SAIC supervised the destruction of monitoring wells MW-6 and MW-7 in August 2008. The <br /> condition of each well was inspected prior to destruction. The total depth of each well was <br /> measured and compared to the well construction logs. RSI Drilling removed the monument <br /> casing and wellhead, and over-drilled each well using a CME-75 truck-mounted drill rig with <br /> 8-inch-diameter, hollow-stem augers. The sand pack and seal were removed by over-drilling to <br /> total depth. The bore holes were backfilled via tremie pipe with neat cement from total depth to <br /> approximately 5 feet bgs, and topped with native soil to ground surface. <br /> SAIC 2009 Request for No Further Action Required Status 14 <br /> SAIC prepared a document summarizing the site investigative activities performed at the site. <br /> Conditions at the site indicate COPC concentrations present in the soil are below screening <br /> levels,with one minor exception. The lateral and vertical extent of affected groundwater is <br /> delineated and limited, and groundwater at the site is unlikely to be used as a drinking water <br /> source. Therefore, SAIC did not recommend preparation of an HHSE or a no further action <br /> required request report. <br /> After notifying property owners within a 200-foot radius of the approximate boundary of <br /> affected groundwater, and receiving no comment, the Central Valley RWQCB determined that <br /> no further action was required for Vernalis Offsitels <br /> 12. SAIC,2008. Soil and Groundwater Investigation Report, Vernalis Offsite, Vernalis, California. June. <br /> 13.SAIC,2008. Groundwater Monitoring Well Destruction Report, Vernalis Offsite, Vernalis, California. November. <br /> 14.SAIC,2009. Request for No Further Action Status, Vernalis Offsite, Vernalis,Stanislaus and San Joaquin Counties, <br /> California. August 14. <br /> 15.RWQCB-Central Valley,2010. No Further Action Required Determination,Vernalis Offsite,Vernalis,Stanislaus and San <br /> Joaquin Counties. June 8. <br /> B-4 The Benham Companies.LLC <br /> P�E�'� A Wholly Owned 5ubsiAiary <br /> From S Axt to SolarAm <br />