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------------------------------ <br /> YES <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 foi, odor <br /> and visual staining. And on subsequent site visits by a WEGE <br /> geologist, field screening with a hand held PID indicated that no <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 Table 3. <br /> Based upon the 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 /> well (WEGE: TABLE 2.) . 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 contoured and a <br /> flow direction inferred (Figure 4A-4I) . <br /> DISCUSSION <br /> Ground water contour maps were developed using the information <br /> obtained during the quarterly monitoring rounds and indicate <br /> apparent flow directions to the northeast, see FIGURES 4A thru 41. <br /> The analytical laboratory results show that TPH and BTEX <br /> concentrations in MW2 and MW3 have always been below reporting <br /> limits (BRL) . Monitor well MWl initially showed ground water <br /> contaminated on June 1 , 1988, with ` ppm gasoline range <br /> hydrocarbons and 41 ppb benzene. Sampling on August 11, 1988 <br /> showed that the gasoline range hydrocarbons were then below <br /> detection limits with 0.6 ppb benzene, which is below the State of <br /> page4 <br />