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07 March 2002 <br /> • AGE-NC Project No 99-0645 <br /> Page 8 of 9 <br /> 4 3 HYDROCARBON-IMPACTED GROUND WATER <br /> After the installation of the ground water wells on the site, ground water monitoring wells were <br /> monitored and sampled Each sample was analyzed for TPH-g, TPH-d, BTEX with analysis for <br /> MTBE, and each sample was analyzed for the suite of nine fuel additives <br />' - TPH and BTEX were not detected in the monitoring well samples <br /> MTBE was detected in the water sample collected from well MW-1 MTBE was detected <br /> by EPA method 8020 at 5 9 micrograms per liter(µg/1)and by EPA method 8260 at 4 7µg/1 <br /> 1 - The remaining fuel additives were not detected <br /> Analytical results from ground water samples are summarized in Table 3 The laboratory report <br />' (MAI Lab ID Numbers 82788 to 82790),QA/QC and chain-of=custody are included in Appendix D <br /> 4 4 GROUND WATER ELEVATION, FLOW DIRECTION AND GRADIENT <br />' A California state-licensed survey engineer from Baumbach&Piazza Inc surveyed a reference point <br /> on the top of each ground water monitoring well casing at the site to the nearest 0 01-foot relative <br /> to the San Joaquin County Bench Mark Datum#N-21 3 The results of the monitoring well survey <br /> are contained in Table 4 The surveying report (Baumbach & Piazza) is presented in Appendix E <br /> Depth to ground water at the site ranged from 90 74 feet to 90 88 feet below the monitoring wells <br /> casing tops Ground water was measured at 91 00 feet below well casing grade in the domestic well <br /> on site The ground water elevation in each well was calculated from these data The ground water <br /> elevations at the site ranged from 45 27 feet to 45 60 feet below mean sea level (msl) <br /> The ground water flow direction and gradient were calculated from the well elevation data The <br /> ground water flow was directed toward the northeast Figure 5 illustrates the contoured ground water <br /> elevations as measured on 02 November 2001 <br /> 5.0. SUMMARY AND CONCLUSIONS <br /> Based on the data collected from the site, AGE finds <br /> Silt with two distinct and extensive sand units appears to underlay the site The sand units <br /> occurred at depths of 15 to 30 feet bsg and 75 or 80 feet to 80 or 85 feet bsg The deepest <br /> sand unit encountered may actually be two thinner units Ground water occurred at <br /> approximately 94 feet bsg <br />' Advanced GeoEnvironmental,Inc <br />