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I I21 December 2001 . 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 MW1, MW2 and MW4 at concentrations ranging from 220 µg/1 in MW2 to 2,500 µg/1 in MW1 TPH-d was detected in the ground water samples collected from all four wells at concentrations ranging from 69 µg/1 in MW2 to 330 µg/1 in MW1 ' Benzene was detected in all four water samples at concentrations ranging from 13 µg/1 in MW3 to 510 µg/1 in MW 1 Toluene, ethylbenzene and xylenes were detected in the water samples collected from MW1,MW2 and MW4 at concentrations as high as 190µg/1 toluene,53 µg/1 ethylbenzene and 170 µg/l total xylenes MTBE was detected by EPA Method 8020 in ground water samples collected from wells MW1, MW2 and MW4 at concentrations of 1,800 µg/1, 310 µg/1 and 200 µg/1, respectively MTBE was confirmed by EPA Method 8260 in the same samples at concentrations of 2,000 µg/l, 320 µg/1 and 220µg/1,respectively and detected in the sample collected from MW3 at a concentration of 2 2 µg11 1,2-DCA was detected in ground water samples collected from MW1 and MW3 at concentrations as high as 36 µg/l(MW 1) EDB and the other fuel oxygenated compounds were not detected in the 10 ground water samples The analytical results of water samples collected in October 2001 are summarized on Table 2 The laboratory report (MAI Lab I D No 81697 through 81700), QA/QC report and chain-of-custody form are included in Appendix B 4.0. SUMMARY AND CONCLUSIONS IThe following conclusions were drawn from the results of this investigation I • The ground water elevations ranged from 8 77 to 9 03 feet above MSL Ground water is inferred to be flowing toward the south-southwest at an average gradient of 0 004 feet/feet The relative ground water elevation at the site increased an average 0 38 feet between the IJuly 2001 and October 2001 monitoring events • Concentrations of dissolved TPH-g,TPH-d,BTEX,MTBE and 1,2-DCA have decreased in all the wells sampled since the last monitoring event in July 2001 The highest concentration of dissolved hydrocarbons occurred in monitoring wells MW1 and MW4 which are south and south-southwest and downgradient of the UST area Isocontour maps depicting the Iapproximate distribution of dissolved TPH-g, MTBE and benzene are presented in Figures . 4, Sand 6 IAdvanced GeoEnvironmental,Inc I