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CLEARWATER <br /> G R O U P [ N C <br /> Eni rrnnnrenf vI Seri ice, <br /> for concentrations of TPHg and BTEX using EPA Methods 5030/8015M/8020 and MTBE by EPA <br /> Method 8260 by Entech Laboratories (Appendix D) <br /> Purging devices were cleaned between use in each well by an Alconox® wash followed by double <br /> rinse in clean tap water to prevent cross-contamination Rinsate was stored on-site in labeled 55- <br /> gallons drums pending future removal and disposal <br /> 5.0 SOIL BORINGS AND MONITORING RESULTS <br /> 5.1 Sedimentological Observations <br /> Subsurface lithologies encountered during drilling consisted predominantly of silty clay with <br /> subsidiary clayey sand with occasional sandy lenses The water table was encountered at <br /> approximately 12 feet bgs Lithologzc correlation between borings is displayed graphically on the <br /> geologic cross-sections presented as Figures 3a, 3b and 3c Detailed soil sample descriptions are <br /> presented in Appendix B This site has been drilled to a maximum depth of 38 feet bgs <br /> 5.2 Soil Sampling Analytical Results <br /> A total of three soil samples collected from each soil boring were analyzed Concentrations of <br /> TPHg and BTEX were only detected in boring MW-5B The highest concentration of TPHg <br /> (1,000 mg/kg) was detected at 25 feet bgs in MW-5B This sample was also analyzed for TPH as <br /> JetFuel and contained 55 mg/kg Detectable concentrations of BTEX were present in soil samples <br /> collected from boring MW-513 at 25 feet and 35 feet bgs MTBE was not detected by EPA method <br /> 8260 in any of the soil samples analyzed <br /> Soil sample analytical results are summarized m Table 1, and displayed in Figure 4 Entech <br /> analytical reports are shown in Appendix D <br /> 5.3 Groundwater Depth, Flow Direction and Gradient <br /> Groundwater was observed beneath the site from 4 71 feet bgs (MW-2) to 9 41 feet bgs (MW-8) <br /> Groundwater gradient was determined to be 0 016 ft/ft to the southeast A groundwater flow and <br /> gradient map for March 9, 2000 is shown in Figure 5 Gauging data are presented in Table 2 and <br /> Appendix C <br /> ZB 178C 5 3/31100 <br />