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1 ' 30 January 2006 . AGE-NC Project No 98-0511 ' Page 3 of 4 ' compounds were detected in wells MW-1 and MW-5 at maximum concentrations in well MW-I of 210 µg/1 benzene, 130 µg/l toluene, 2,000 µg/1 ethylbenzene, and 11,000 µg/l xylenes Maps showing the approximate distributions of dissolved TPH-g and benzene at the site are illustrated on ' Figures 4 and 5, respectively MTBE was detected in the ground water sample collected from well MW-5 at a concentration of ' 47 µg/l No other constituents of concern were detected at or above laboratory reporting limits Analytical ' results of ground water samples are summarized in Table 2 Copies of the laboratory report(CTEL Project No CT214-0509037), quality assurance/quality control (QA/QC) report, and chain of custody forms are provided in Appendix C Documents confirming the upload of laboratory ' electronic deliverable format (EDF) files and depth to water measurements to GeoTracker are provided in Appendix D ' 4.0. SUMMARY AND CONCLUSIONS ' • Based upon data collected from the site during the September 2005 investigation, AGE concludes the following ' Depths to ground water ranged from 17 06 feet to 17 56 feet below the tops of the well casings Ground water elevations at the site ranged from 0 31 feet above MSL to 1 16 feet above MSL and averaged 0 76 feet above MSL, indicating a decrease in ground water elevation of approximately 2 58 feet since the last monitoring event in June 2005 • Ground water at the site was inferred to flow toward the southwest on the southern portion Iof the site and radially inward toward a depression in the potentiometric surface near well MW-5 on the northern portion of the site,calculated gradients ranged between 0 007 ft/ft and 0 015 ft/ft The historical flow direction across the UST area was west to northwest ' TPH-g was detected in the ground water samples collected from monitoring wells MW-1 and MW-5 at concentrations of 15,000 gg/l and 2,400 gg/l,respectively BTEX compounds were detected in wells MW-I and MW-5 at maximum concentrations in well MW-1 of 210 gg/l benzene, 130 gg/l toluene, 2,000 µg/1 ethylbenzene, and 11,000 µg/l xylenes The detected concentrations of benzene in wells MW-1 and MW-5,and ethylbenzene and xylenes in well I MW-1,were above the DHS' maximum contaminant levels(MCLS)for these contaminants in drinking water • MTBE was detected in the ground water sample collected from well MW-5 at a concentration of 47 gg/l, this concentration is above the MCL (13 gg/l) for MTBE in drinking water However, the MTBE concentrations in well MW-5 have been consistently Advanced GeoEnwonmentai,Inc I