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i <br /> i <br /> • 30 October 2000 <br />' AGE-NC Project No 99-0657 <br /> Page 3 of 4 <br /> Benzene was detected in all four water samples at concentrations ranging from 2 0 µg/1 in MW3 to <br /> 590µg/l in MW4 Toluene,ethylbenzene and xylenes were detected at concentrations as high as 410 <br /> µg/l, 93 µg/1 and 460µg/l, respectively(MW4) In the ground water samples collected from MW1, <br /> IMW2 and MW4 <br /> MTBE was detected in ground water samples from wells MW 1 through MW4 at concentrations of <br /> 150µg/l, 1,100µg/l, 1 1 µg/l and 150µg/l,respectively TAME was only detected in sample MW2 <br /> at a concentration of 7 5 4g/1 TBA was detected in the ground water samples collected from MW1, <br /> MW2 and MW4 at concentrations of 25 µg/1, 350 µg/l, and 45 µg/1, respectively 1,2-DCA was <br /> detected in all four water samples at concentrations as high as 27µg/1 (MW4) EDB was detected <br /> in the water samples collected from MW1 and MW4 at concentrations of 0 91 /zg/l and 2 1 µg/l, <br /> respectively <br /> The analytical results of water samples collected In October 2000 are summarized on Table 2 The <br /> laboratory report (AAL Order No A00100420), QA/QC report and chain-of-custody form are <br /> included In Appendix B <br /> 10 4.0. SUMMARY AND CONCLUSIONS <br /> The following conclusions were drawn from the results of this investigation <br /> • The ground water elevations ranged from I1 00 to 1131 feet AMSL Ground water Is <br /> flowing toward the southwest under an average gradient of 0 005 feet/feet The relative <br /> ground water elevation at the site increased an average of 1 56 feet between the July 2000 <br /> and October 2000 monitoring events <br /> • Concentrations of dissolved TPH-g, TPH-d, BTEX compounds and fuel oxygenates have <br /> decreased significantly in momtonng wells MW 1,MW3 and MW4 since the last monitoring <br /> event In July 2000 The hydrocarbon concentrations have increased in MW2 The highest <br /> concentration of dissolved hydrocarbons Is in monitoring well MW4 which is <br /> south-southwest and downgradnent of the UST area <br /> • The lateral extent of petroleum hydrocarbon impacted ground water has not been defined <br /> Advanced GeoEnvlronmental,Inc <br /> I <br />