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• 01 May 2003 AGE-NC Project No 99-0657 Page 3 of 4 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES TPH-g was detected in the water samples collected from wells MWl through MW6 at a maximum I concentration of 3,500 micrograms per liter (µg/l) in sample MWl TPH-d was only detected In sample MW 1 at a concentration of 280 µg/1 One or more BTEX compounds were detected in water samples collected from wells MW1 through MW6 with maximum concentrations of 160 µg11 benzene, 9 0 µg/1 toluene, 10 µg/l ethylbenzene and 170 µg/1 xylenes in MW-1 MTBE was detected in water samples collected from wells MW 1 through MW6 at a maximum concentration of 1,800 µg/1(MWl) TAME was detected in the water samples collected from.well ' MW2 at a concentration of 2 6 µg/1 1,2-DCA was detected in water samples collected from MWl, MW4 and MW6 at a maximum ' concentration of 37 µg/1 (MWl) • No other fuel additives were detected at or above laboratory detection limits in the ground water ' samples analyzed The analytical results of water samples collected in January 2003 are surninarized on Table 2 The laboratory report (CTEL Lab Project No CT214-0301017), QA/QC report and ' chain-of-custody form are included in Appendix C ' 4.4. SUMMARY AND CONCLUSIONS The following conclusions were drawn from the results of this investigation ' 0 The ground water elevations ranged from 5 87 to 6 27 feet above MSL Ground water is inferred to be flowing toward the southwest with an average ground water gradient of 0 003 feet/feet The ground water elevation at the site decreased an average 0 11 feet between ' the October 2002 and January 2003 monitoring events • The highest concentrations of dissolved hydrocarbons occurred in.monitoring wells MW1, ' MW4 and MW6,which are located down-gradient of the UST area Iso-concentration maps depicting the approximate distribution of dissolved TPH-g,benzene and MTBE are presented in Figures 4, 5 and 6 1 0 Concentrations of dissolved TPH-g, TPH-d, BTEX have remained relatively stable, while concentrations of dissolved MTBE, EDB and 1,2-DCA have increased from the previous l quarter Although there appears to be a general decline in overall concentrations, cyclical . highs and lows are apparent in the data, with higher reported concentrations generally encountered during higher ground water periods Advanced GeoEnvironmental,Inc