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1 <br /> TREADWELL & ROLLO <br /> o converted the exploratory boring into a monitoring well (MW-1) <br /> o developed the monitoring well (MW-1) and collected a groundwater sample <br /> o analyzed one soil sample and one groundwater sample for total petroleum <br /> hydrocarbons as diesel (TPHd) and benzene, toluene, ethylbenzene, and xylenes <br /> (BTEX) <br />' o reviewed and assessed the analytical results and prepared this report. <br />' 4.0 FIELD INVESTIGATION <br />' A boringwas drilled in the resumed down adient direction from the former storage <br /> P �' � <br />' tank excavation (Figure 2) and converted into a monitoring well (MW-1). The location <br /> of the well was based on the analytical results from our previous investigation. Gregg <br />' Drilling & Testing, Inc of Pacheco, California, performed the drilling and well <br /> installation on 29 September 1993, under the direction of Treadwell & Rollo, Inc. <br /> The borehole was advanced using a truck-mounted drill ng equipped with six-inch- <br /> diameter, hollow-stem augers. It was drilled to a depth of approximately 21 feet. All <br /> augers were steam-cleaned prior to use, and the sampling equipment was cleaned <br />' between sampling intervals with a tnsodium phosphate solution and rinsed with clean <br /> water. All soil cuttings and purged groundwater were placed in 55-gallon drums which <br />' were sealed, labeled, and stored onsite. <br />' 4.1 Subsurface Soil Sampling <br /> The soil samples were obtained using a California Modified, split-spoon sampler with an <br />' outside diameter of 2.5 inches. The split spoon sampler was lined with clean, six-inch- <br /> long, two-inch-diameter, stainless steel tubes. The sampler was driven with a 140-pound <br /> 3 <br /> 11070707 PJC 18 November 1993 <br /> I <br />