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Z�u -� _ _� � <br /> YES to both. <br /> 6. Were soil samples taken for every 20 linear feet of <br /> underground piping? <br /> NO. Field screening of the trenches left from the removal of the <br /> underground piping was performed by Walton Engineering for odor <br /> and visual staining. And on subsequent site visits by a WEGE <br /> geologist, field screening with a hand held PID indicated thatno <br /> Petroleum hydrocarbon contamination existed along the product line <br /> trenches. <br /> 7. Were depth and location of soil samples submitted? <br /> YES, see Figure 3B and Tab2e '3. <br /> Based upon eche preceding information and the monitoring that WEGE <br /> has performed, this site should be considered for closure. We <br /> feel the gasoline range hydrocarbons found in the initial sampling <br /> of the ground water associated with the tank excavation and <br /> monitor well MW1 were very limited in extent and have been <br /> remediated via natural evaporation and dilution methods. <br /> SITE INVESTIGATION <br /> The ground water was sampled in the three onsite monitoring wells <br /> by a Western Geo-Engineers (WEGE) geologist. Surface elevation, <br /> depth to water and ground water elevation were recorded for each <br /> W811 (WEGE: TABLE 1) . No floating product was observed in any of <br /> the wells. Each well was sampled after 5 bailers (approximately 2 <br /> gallons) of water were removed; the "purged" water was "contained" <br /> in .a labeled,, secured 55 gallon drum on site. This water was <br /> later removed and disposed of at the Tracy Water Treatment ` Plant. <br /> From the well information, the ground water was contouree. and a <br /> flow direction inferred (Figure 4A-4I) . <br /> DISCUSSION <br /> Ground water contour maps were developed using the informatio- <br /> Nn <br /> obtained during the quarterly monitoring rounds and indicate <br /> apparent flow directions to the northeast, see FIGURES 4A thru 4I. <br /> The analytical laboratory reLults show that TPH and BTEX <br /> concentrations in MW2 and MW3 have always been below reporting <br /> limits (BRL) . Monitor well HWI initially showed ground water <br /> contaminated on June 1, 1988, with 4 ppm gasoline range <br /> hydrocarbons and 41 ppb benzene. Sampling on August 11, 2988 <br /> -- - ----------.—showed—that—the--gasol-i.ne-range---hydrocarbons--wexe-then below -- - ---- - <br /> �' detection limits with 0.6 pp> benzene, which is below the State of <br /> page4 <br /> 1 <br /> `f <br />