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I <br /> r■rr�ruAM <br /> Working to Restore Nature <br /> Drilling and Soil Sampling <br /> On December 3, 1993, a geologist from RESNA observed Woodward Drilling of Rio Vista, <br /> California, drill two soil borings (B-20 and B-21) to approximately 32 feet below grade, <br /> groundwater was not encountered. The locations are shown on the Generalized Site Plan <br /> (Plate 2) Soil samples were collected at approximately 5-foot intervals during drilling, <br /> identified using visual and manual methods, and classified according to the Unified Soil <br /> Classification System (Plate 3) The soil samples were also screened in the field using a <br /> photoionization detector (PID) Sediments encountered during drilling were silt with minor <br /> amounts of clay and fine-grained sand Following soil boring, vapor extraction wells VW-5 <br /> and VW-6 were installed in borings B-20 and B-21, respectively Descriptions of the <br /> materials encountered, details of well construction, and PID readings are presented in the <br /> Logs of Borings (Plates 4 through 7) Drill cuttings remain stockpiled onsite, on and <br /> covered by plastic sheeting, pending disposal <br /> Laboratory Analyses and Results <br /> The soil samples collected from 15 and 30 feet below surface grade from borings B-20 and <br /> B-21 were submitted to Sequoia Analytical of Sacramento, California for analysis for total <br /> petroleum hydrocarbons as gasoline (TPHg) using Environmental Protection Agency(EPA) <br /> Methods 5030 and 8015 and benzene, toluene, ethylbenzene, and total xylene isomers <br /> (BTEX) using EPA Methods 5030 and 8020 Copies of the Chain of Custody Records and <br /> laboratory reports are attached <br /> Concentrations of TPHg ranged from 15,000 to 66,000 parts per million in the samples <br /> collected from boring B-20, but were below laboratory detection limits in the samples <br /> collected from boring B-21 Results of analysis for TPHg and BTEX are presented in Table <br /> 1 <br /> WORK IN PROGRESS <br /> Vapor extraction wells VW-5 and VW-6 will be used in conjunction with vapor extraction <br /> wells previously installed at the site for remedial system design and implementation <br /> 1214dcam/3W32-14 3 <br />