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3 February 28, 1992 <br /> Mr. Chris Stock <br /> 3.0 SITE INVESTIGATION <br /> 3.1 Drilling and Soil Sampling <br /> Two soil borings :were drilled and. sampled -during this investigation of the site <br /> (Figure 2). These borings were located on either side of the underground gasoline.- <br /> storage <br /> asoline.storage tank to try to determine if the contents have impacted soils ,:within the vadose <br /> zone. The drilling program was performed on January 24, 1992 using a MobileTM 8-53 <br /> truck mounted drill rig equipped with 8-inch diameter hollow-stem augers. <br /> Soils were sampled at five foot intervals in the borings to a (depth of�30 ;feet in order <br /> to obtain stratigraphic data. Soil samples were collected in each, of� the borings using <br /> a split-spoon sampler (ASTM D 3550 with shoe similar to ASTM D 1586) equipped with <br /> six 3-inch by 2.5-inch diameter stainless steel or brass sleeves for soil retention. The <br /> soil samples were. obtained .by driving the sampler with a. one hundred and forty <br /> pound hammer dropping thirty inches in accordance with. ASTM D 1586. <br /> i <br /> The lowermost sleeve at each sample interval (corresponding to approximately . 18 <br /> inches below the actual sample interval) was screened for. total organic vapors with a <br /> photo-ionization detector (PID). The PID utilized an 11.7 eV lamp' 'and was- calibrated <br /> with a standard of isobutylene gas :at a concentration of 100. arts per million. <br /> P <br /> Headspace vapor analysis was per formed by first discarding. a portion of the soil <br /> retained at one end of the sleeve 'to produce,,a headspace. The sleeve was then capped <br /> and the probe of -the �PID was. inserted through a hole in the cap and into the <br /> headspace for analysis. The .PID readings are recorded on the boring logs. <br /> The second sample sleeve .was immediately sealed with Teflon® film, capped, and <br /> placed.: on ice for transport to °Eureka -Laboratories in Sacramento, a California <br /> Department of Health Services (DOHS) certified laboratory. Strict chain .of custody <br /> procedures were utilized for all samples collected. <br /> All sampling equipment was washed 'with TSP (tri-sodium phosphate). cleanser,` pre< r <br /> rinsed with tap water' and °a final rinse of de-ionized water prior, to sampling, f <br /> between sample intervals, and between borings to minimize the possibility of cross- <br /> contamination. After drilling and . sample collection, the bo'ring's were backfilled <br /> f <br /> EK-6014-1 9202-E100.RPT ' <br />