ARCHIVED REPORTS_XR0006880- CASE 2

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13 March 2003 S AGE-NC Project No 97-0351 tPage 3 of 4 • TPH-g was detected In the samples from ground water monitoring wells MW-1 and ' MW-UST at concentrations of 2,800 micrograms per liter(µg11)and 2,200µg/1,respectively • BTE&X compounds were detected in the sample from monitoring well MW-1 at concentrations of 120 µg/1 of benzene, 8 9 µg/1 of toluene,24 µg/1 of ethylbenzene and 35 7 _ µg/1 of total xylenes BTE&X compounds were not detected In the samples collected from wells MW-2 through MW-5 and MW-UST ' MTBE and other fuel additives were not detected in the samples collected from wells MW-1 through MW-5 and MW-UST 1 Laboratory results of samples analyzed for petroleum hydrocarbons are summarized In Table 2 and Table 3 The laboratory report (CTEL Project No CT214-0302026) and chain-of-custody form are ' Included in Appendix C ' 4.0 SUMMARY AND CONCLUSIONS '• Based upon the results of this quarterly monitoring event, AGE concludes • The ground water flow direction was Inferred to be northeast at a gradient of approximately 0 001 ft/ft which is consistent with previously determined flow directions and gradients • The highest concentrations of dissolved petroleum hydrocarbons were detected in samples collected from well MW-1,near the former UST location TPH-g declined significantly in ' monitoring wells MW-1 and MW-UST when compared to the last quarterly event in September 2002 BTE&X compounds in MW-1 also declined significantly since the last quarterly event ' • The b enzene c oncentration i n w ell M W-1 i s s ignificantly above t he D HS's Maximum Contaminant Level of 10 gg/1 in drinking water ' • At the present time,neither the vertical extent nor the western lateral extent of the dissolved hydrocarbons have been defined 1 5.0. RECOMMENDATIONS ' Based on the results of this investigation, AGE recommends • Continued quarterly ground water monitoring, the next monitoring event is scheduled for ' Apn12003 • Advanced GeoEnvironmental,Inc