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"4 <br /> • Pacific Gas and Electric <br /> • Pacific ` oleI)hone <br /> • US Sprint <br /> • Continental Cable, and <br /> • California Nater Service. <br /> None of these companies reported underground utility lines ut the <br /> site. <br /> Soil borings were placed in the area of the former excavation in order <br /> to obtain a preliminary assessment of the horizontal and vertical <br /> extent of the contamination kFigure 1.-a0. 'I'lu•ee borings (3, 6, and J) <br /> were selected in areas of known ContaiiiinaLion to determine the <br /> v,:rtical extent of contamination. Seven other sainplirigoatlocations <br /> were selected around the perimeter to provide a preliminary <br /> assessment of the horizontal extent of contamination. <br /> Borings were drilled using a truck-mounted drilling rig equipped <br /> with continuous flight augers. All drilling and sampling equipment <br /> was steam cleaned prior to drilling each boring to prevent <br /> contamination between borings. Borin;s were <br /> logged <br /> naccordance <br /> with the Unified Soil <br /> tem (See Appendix ) The <br /> boring logs may <br /> bea � n p�endix C <br /> Sampling commenced at the interface between the fill material and <br /> the native subsoil. Samples for laboratory analysis were taken with a <br /> r California Modified Split-spoun sampler equipped with brass tubes. <br /> without brass tubes for r.ureases of <br /> Several samples were taken <br /> logging relatively undisturbed soils. The samples were .b5erved for <br /> ter_ture, moisture, and staining or odor. Sairples we=e taken to <br /> eld, In <br /> characterize the level of c!e samplelit yes �ollect d in every served in the boring to <br /> addition, a bottom-of-the-ho <br /> verify any Cc:d observed absence or presence of contamination. <br /> After the last sample from each boring was collected and observed for <br /> signs of contamination, two to three samples were selected for <br /> analysis. Sample selection wthe�erttical extentand <br /> of the contamination <br /> with the objective of defbservation <br /> ining . <br /> r (PID} was also employed <br /> in each baring. A photoionisation detector <br /> initially to help detect petroleum hydrocarbon vapors in the sail <br /> samples. Howevo , due to the low volatility of the contaminants, the <br /> PTD tended to pul: in inure ambient air than volatilized contaminants <br /> which resulted in very low ieP�ngs even <br /> e,ntbleeuseelof the PlDpersonnel nwas <br /> strong petroleum odors. <br /> discontinued after the third boring. <br />