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The downhole drilling equipment was steam cleaned to prevent cross- <br /> contamination between boreholes. Sampling equipment was cleaned after each <br /> sampling event by washing it in a Liquid-Nox solution followed by rinsing first <br /> with tap water and then with distilled water. All rinsate generated by steam <br /> cleaning and sampler cleaning operations was contained and then placed in two <br /> marked 55-gallon drums and securely stored in the designated area. <br /> Upon completion, the borings were backfilled from bottom to surface with a <br /> cement grout containing approximately 5% bentonite. The ground surface <br /> elevations at each of the borings were surveyed by ATEC. The depth to <br /> groundwater was measured to the nearest 0.01-foot using a Solnist water level <br /> probe (refer to Appendix B-Boring Logs for groundwater levels). <br /> 3.4 Sampling Methods <br /> In soil borings B-1 and B-3, one soil sample was collected from the capillary <br /> fringe, immediately above the water table. One soil sample was collected from <br /> 5 feet below ground surface (bgs) in soil boring B-2. Soil boring B-4 was placed <br /> at the approximate location of the former UST excavation and one soil sample <br /> was collected from 15 feet bgs which was the estimated depth of the bottom of <br /> the UST excavation. A total of 4 soil samples were collected by utilizing a <br /> hammer-driven, California Modified Split-Spoon Sampler. <br /> 5 <br />