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' 19 January 2004 • AGE-NC Project No 95-0130 ' Page 4 of 6 4.0. SUMMARY AND CONCLUSIONS ' The implications from the August 2003 round water monitoring event are as follows p g g g ' • Ground water at depths between 35 and 80 feet bsg (Hydrologic units 1, 2 and 3) was infei red to be towards the not theast at a gradient of 0 004 feet/feet or less (Figures 3 and 4) • Between Tanuaty 1995 and August 2001, ground water elevations at the site generally increased from 44 feet to 23 feet below MSL, since August 2001 and present day, ground watei elevations have generally fluctuated between 24 feet and 27 feet below MSL(Table 2) • The decrease of ground water elevation of approximately 1 13 feet between the June 2003 and the August 2003 monitoring events may be due to seasonal ground water fluctuation • Ground water at the site was generally observed between 42 and 43 feet bsg and was above the screened inteivals of wells MW-1 through MW-5, MW-6 (B-E), MW-7(B-E), VW-1C, VW-2A and VW-3A (i e screened below ground water elevation), and may not yield ' samples frilly i epresentative of shallowest ground water conditions • The greatest concentrations of Top Filling Station dissolved TPH-g and BTEX were detected in samples collected from well VW-2A(Figures 4 and 6, area immediately north of the office building) which is consistent with previous monitoring results TPH-g concentrations were detected as high as 150,000 pg/l from well VW-2A ' • The greatest concentrations of Top Filling Station dissolved MTBE were detected in the samples collected from wells VW-3A and MW-6B (Figures 5 through 8) which is located immediately south and southeast of the office building • Significant concetltratioiis of 1,2-DCA were detected or have consistently been detected from wells MW-2, MW-3, MW-6B, MW-GC, MW-7A, MW-7B, VW-1B, VW-1C, VW-2A, VW-2B and VW-3A indicating a significant 1,2-DCA-impact to ground water at the site • TBA was not detected in any of the analyzed water samples, however, TBA was previously detected in wells MW-1, MW-2, MW-3, MW-5, VW-1C, VW-2A, VW-2B and VW-3A, suggesting a significant TBA-impact to ground water at the site • EDB has previously been detected in wells MW-7B, VW-1B, VW-1C and VW-2A in concentrations significantly above the DHS's Maximum Contaminant Level (MCL) in drinking water I • The high concentrations of petroleum hydrocarbons detected in samples collected from wells MW-6 (A and B), MW-7 (A and B), VW-1 (B and C), VW-2A and VW-3A indicated that these wells ate within or near the dissolved petroleum hydrocarbon"core area"of the plume (Figures 5 through 8) Advanced GeoEnvironmentai,Inc