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r <br /> Work Plan for Additional Site Investigation 2 <br /> March 27, 1997 <br /> The Southland Corporation,4627 DaVinci Drive,Stockton,CA <br /> A search of appropriate agency files will be conducted to determine the location of any water supply wells <br /> within 2,000 feet of the subject site. Permits for drilling and well installation will be obtained from SJCPHS. <br /> TASK 2: SOIL BORINGS/SOIL SAMPLING <br /> Fluor Daniel GTI will drill four soil borings at the locations shown on the attached figure using a <br /> truck-mounted drill rig equipped with 8-inch-diameter hollow-stem augers. The borings will be drilled to <br /> approximately 15 feet below ground surface (BGS), and will be used to characterize and delineate the <br /> extent of adsorbed petroleum hydrocarbons. It is anticipated that groundwater will be encountered <br /> approximately 8 feet BGS. <br /> Soil samples will be collected from each soil boring at 5-foot intervals to a total depth of 15 feet BGS <br /> beginning at 5 feet BGS using a split-spoon sampler lined with 2-inch-diameter by 6-inch-long brass <br /> sample tubes. If field observations indicate the soil sample collected at 15 feet BGS contains elevated <br /> concentrations of petroleum hydrocarbons the boring will be extended to 20 feet BGS. The <br /> hollow-stem augers will be steam cleaned before drilling, and sampling equipment will be cleaned <br /> between each sampling interval. Each soil sample will be screened for hydrocarbon vapors using a <br /> photoionization detector(PID). Soils encountered during drilling will be logged using the Unified Soil <br /> Classification System by a Fluor Daniel GTI field geologist,working under the supervision of a <br /> California registered geologist. One sample tube from each sampling interval will be sealed with teflon <br /> sheets, capped,taped, labeled, and placed on ice in an insulated container. Based on field <br /> observations, selected soil samples from each borehole will be analyzed by a State-certified analytical <br /> laboratory for benzene,toluene, ethylbenzene and xylenes (BTEX), methyl-tert-butyl-ether (MTBE), <br /> and total petroleum hydrocarbons-as-gasoline (TPH-G) by EPA methods 8020/8015 modified. An <br /> estimated two soil samples from each boring will be analyzed. <br /> All soil generated through drilling will be placed in Department of Transportation (DOT)-approved <br /> 55-gallon drums pending characterization and disposal. Water generated by steam cleaning will be <br /> temporarily stored on site in DOT-approved 55-gallon drums pending characterization and disposal. <br /> TASK 3: WELL CONSTRUCTION/DEVELOPMENT/GAUGING/SAMPLING <br /> A groundwater monitoring well will be constructed in each boring of 2-inch diameter Schedule 40 poly- <br /> vinyl-chloride (PVC) casing with flush threads and 0.020-inch-slot well screen. The well screen for <br /> each monitoring well will be installed from approximately 5 to 15 feet BGS. The wells may be installed <br /> to 20 feet BGS if field observations indicate that petroleum hydrocarbons have migrated vertically below <br /> 15 feet BGS. A sand filter pack will be placed around the well screen to a maximum height of 1 foot <br /> above the top of the screen. The well will be sealed with 2 feet of hydrated bentonite, followed by a <br /> neat-cement grout to grade containing a mixture of 95 pounds of Portland Type 1/II cement to 5 gallons <br /> 0497WKP LTR SOLJTHLAND-59 <br /> ►Im� <br /> FLUOR DANIEL GTI J <br />