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1 ' 27 August 2001 • AGE-NC Project No 99-0657 Page 3 of 4 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES TPH-g was detected In all four ground water samples collected at concentrations ranging from 330µg/1 m MW2 to 5,300 µg/1 in MW 1 TPH-d was also detected in the four groundwater samples at concentrations ranging from 60 µg11 in MW2 to 890 gg/1 in MWl Benzene was detected in all four water samples at concentrations ranging from 15 µg/1 in MW3 to 1,000 gg/1 in MW1 Toluene, ethylbenzene and xylenes were detected in all of the ground water samples collected,with the exception of ethylbenzene in MW3 at concentrations as high as 530 µg/1 toluene, 89 µg/1 ethylbenzene and 390 µg/1 total xylenes MTBE was detected by EPA Method 8020 in ground water samples collected from wells MW1 through MW4 at concentrations of 2,300µg/1, 1,500µg/1, 17µg/1 and 660 gg/l,respectively MTBE was confirmed by EPA Method 8260 in the same samples at concentrations of 2,400µg/l, 1,600 pg/l, 12 µg/1 and 700 µg/1, respectively 1,2-DCA was detected in ground water samples collected from MW1, MW3 and MW4 at concentrations as high as 61 µg/1 (MW1) EDB and the other fuel oxygenated compounds were not detected in the ground water samples �. The analytical results of water samples collected in July 2001 are summarized on Table 2 The laboratory report (MAI Lab I D No 72129 through 72132), QA/QC report and chain-of-custody Iform are Included in Appendix B 4.0. SUMMARY AND CONCLUSIONS The following conclusions were drawn from the results of this investigation • The ground water elevations ranged from 8 38 to 8 67 feet above MSL Ground water is Inferred to be flowing toward the southwest at an average gradient of 0 005 feet/feet The relative ground water elevation at the site decreased an average 0 72 feet between the April 2001 and July 2001 monitoring events • Concentrations of dissolved TPH-g, TPH-d, BTEX compounds and fuel oxygenates have decreased in wells MW 1,MW2 and MW3 and remained relatively stable in well MW4 since the last monitoring event in April 2001 The highest concentration of dissolved hydrocarbons Is in monitoring wells MW 1 and MW4 which are south and south-southwest and downgradient of the UST area Isocontour maps depicting the approximate distribution of dissolved TPH-g, MTBE and benzene are presented in Figures 4, 5 and 6 I • The lateral and vertical extent ofpetroleuin hydrocarbon-Impacted ground water has not been adefined Advanced GeoEnvironmentai,Inc