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1 ' 27 September 2004 AGE-NC Project No 96-0263 ' Page 4 of 5 ' MW-2, MW-4 and MW-7 at concentrations of 4 2 gg/l, 6 0 µg/1 and 16 gg/l, respectively Total xylenes were detected in samples MW-2, MW-4, MW-5, MW-7 and MW-9 at concentrations ranging from 3 4 µg/1 (MW-9)to 24 gg/1 (MW-7) MTBE was detected in samples MW-2, MW-4, ' MW-5 and MW-7 at concentrations ranging from 140 gg/1(MW-4)to 4,900 gg/l (MW-7) TAME was detected in sample MW-7 at a concentration of 6 9 µg/1 No other fuel additives were detected in the ground water samples collected from the site ' The current and past ground water sample analytical results are summarized in Tables 2 and 3 Copies of the laboratory report (CTEL Project No CT214-0403226), quality assurance/quality control (QA/QC) report and chain-of-custody forms are in Appendix C GeoTracker confirmation pages of the submitted laboratory electronic deliverable format(EDF)files are included in Appendix D 4.0. SUMMARY AND CONCLUSIONS Based on the results of this investigation, AGE concludes that ' . Depth to ground water ranged from 7 25 feet to 8 35 feet below the tops of the well casings Ground water elevations at the site ranged from 28 52 feet above MSL in well MW-9 to 29 41 feet above MSL in well MW-1 The ground water at the site was inferred to be flowing to the north-northwest at an average gradient of 0 005 foot/foot • Target analytes, including TPH-g,BTEX components,MTBE and/or TAME were detected in ground water samples collected from wells MW-2, MW-4, MW-5 and MW-7 Detected concentrations of target analytes were generally consistent with previous results from ground water analyses MTBE concentrations have remained relatively stable since monitoring began • The dissolved hydrocarbon plume extends northward from the former UST and dispenser areas, but not beyond the down-gradient monitoring wells (MW-8 and MW-10) The dissolved phase plume has been defined laterally in all directions, except for the minor benzene detection at well MW-9 lsoconcentration maps illustrating the approximate extent of TPH-g, benzene and MTBE-impacted ground water are depicted on Figures 4, 5 and 6 I5.0. RECOMMENDATIONS Based on the findings of this investigation AGE recommends continued quarterly monitoring of the ground water monitoring wells and operation of the ozone sparge system Advanced GeoEnviranmental,Inc I