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' 04 November 2002 . AGE-NC Project No 95-0109 Page 3 of 4 ' 3 2 PETROLEUM HYDROCARBON-IMPACTED GROUND WATER Petroleum hydrocarbons were detected in ground water samples from wells MW-8, MW-9 and ' MW-14 TPH-g was detected at concentrations as high as 4,900 micrograms per liter(µg/1)(MW-9) BTEX compounds were detected in samples from the same wells at concentrations as high as 77µg/1 benzene (MW-14), 7 6 µg/1 toluene (MW-8), 310 µg/1 ethylbenzene (MW-9) and 210 µg/l total ' xylenes (MW-8) The fuel additive 1,2-DCA was detected in samples collected from wells MW-,7,MW-9 and MW-14 ' at concentrations as high as 51 pg/l (MW-9) In addition, TBA was detected in the water samples collected from wells MW-9 and MW-14 at concentrations of 53 µg/1 and 7 5 µg/l, respectively ' No other target analytes were detected in the samples collected The approximate extent of dissolved TPH-g, benzene and 1,2-DCA are depicted on Figures 4, 5 and 6 The analytical results for the ' September 2002 monitoring event are presented on Table 2 Historical analytical results are summarized on Table 3 The laboratory report (MAI Laboratory I D Nos 0209239-001 through 0209239-005) and chain-of-custody forms are included in Appendix B 1 4.0. DISCUSSION AND CONCLUSIONS ' Based upon data collected from the site, AGE finds • Ground water elevation decreased an average of 1 97 feet between the June 2002 and ' September 2002 sampling events The ground water flow direction was inferred to radiate outward between a west-southwest direction at the western edge and a southerly direction ' at the central portion of the site • Hydrocarbon concentrations in ground water remained relatively stable in the samples collected from wells MW-8 and MW-9, decreased in well MW-14 and remained below ' laboratory detection limits in samples collected from MW-7 and MW-12 compared to results of the previous sampling event ' • Benzene concentrations in wells MW-8 and MW-9 were above the DHS's Maximum Contaminant Level (MCL) of 10 µg/1 in drinking water • 1,2-DCA were detected in samples collected from wells MW-7, MW-9 and MW-14 at ' concentrations above the MCL of 0 5 µg/1 in drinking water 1,2-DCA was not detected in the water sample collected from MW-12 for the fourth consecutive quarter • The extent of petroleum hydrocarbon-impacted ground water appears to be contained within . the current network of on-and off-site wells The extent of 1,2-DCA impacted ground water also appears to be contained within the current well network Advanced GeoEnvironmental,Inc t