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' 06 December 1999 • AGE-NC Project No 95-0111 ' Page 3 of 4 Benzene was detected in samples collected from wells MW-1 and MW-2 at concentrations of 7 5 µg/l and 3 5 ug/l, respectively Ethylbenzene was detected in well MW-2 at a concentration of 21µg11 Xylenes were detected in samples from wells MW-1 and MW-2 at concentrations of 13µg/1 MTBE was detected by EPA Method 8260 Modified in samples collected from wells MW-1, MW- 3,MW-4, MW-5 and MW-7 at concentrations of 170µg/1, 2 1 µg/l, 8 1 µg/1, 8 7 µg11 and 7 7µg/l, ' respectively Analytical results of ground water samples are summarized in Table 2 and Table 3 The laboratory ' report(MAI Laboratory Sample Nos 19829 to 19836), quality assurance and quality control report and chain-of-custody form are included in Appendix B 14r 4.0. SUMMARY AND CONCLUSIONS ' Based upon data collected from the site during the current and preceding ground water monitoring events, AGE concludes lie The ground water flow direction inferred from data collected during this monitoring event is consistent with ground water flow directions determined during past events at the site ' • Except for TPH-g and TPH-d in the sample from well MW-5, the concentrations of TPH-g and BTEX detected in the ground water samples remain near the low range of concentrations previously detected The TPH-d concentration in the sample from well MW-5 remains at the ' low end to medium range of concentrations previously detected • Relatively high concentrations of TPH-d in MW-4 and MW-5 demonstrates the presence of ' a persistent plume of dissolved diesel fuel in ground water along the north edge of the site ' 5.0 RECOMMENDATIONS Based on present site conditions, AGE recommends • The next quarterly monitoring should be scheduled for December 1999 • At the conclustion of collecting one-year of monitoring data from wells MW-7 and'MW-8, all data will be reviewed to evaluate the site for a closure recomendation ' Advanced GeoEnvironmental Inc _ t ,