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I 1 May 2004 AGE-NC Project No 95-0141 Page 4of5 4.0. SUMMARY AND CONCLUSIONS The findings of the First Quarter 2004 site investigation event include the following • At the time of the March 2004 ground water monitoring event, ground water elevations at the site ranged from 12 17 feet to 13 51 feet below MSL The shallow ground water was inferred to flow generally toward the southeast, at a gradient of 0 005 foot/foot whale the deeper ground water zone was inferred to flow generally toward the east-southeast, at a gradient of 002 foot/foot Wells MW-3 through MW-5 were"drowned",and likely dad not yield samples fully representative of ground water conditions near the top of the saturated zone, where fuel hydrocarbons would be expected to have the greatest impact • During the first quarter 2004, TPH-g was detected an ground water samples collected from five of the fifteen wells at the site at concentrations as high as 110,000µg/1 TPH-g-impacted shallow ground water has been defined(Figure 5) However,the TPH-g-impact to the deeper ground water zone has not been defined toward the east and to a lesser degree south and north (Figure 6) . During the first quarter 2004, various BTEX constituent was detected an five of the fifteen wells ground water wells The detected benzene concentrations in all five wells exceeded the DHS' Maximum Contaminant Level (MCL) for benzene an drinking water and the concentrations of toluene, ethylbenzene and total xylenes in well EX-1 were significantly above their respective MCLs However, the use of the shallow and deeper ground water an the region does not immediately appear to be for domestic use During the first quarter 2004, 1,2-DCA was detected an ground water samples collected from eight of the fifteen wells at the site at concentrations as high as 190 gg/l(EX-1) The detected concentrations of 1,2-DCA were above the MCL 1,2-DCA-impacted shallow ground water has not been defined toward the east, and 1,2-DCA-impacted deeper ground water zone has not been defined toward the south, east and north Again,the use of the shallow and deeper ground water an the region does not immediately appear to be for domestic use A map illustrating the approximate extent of 1,2-DCA in shallow and deep ground water as presented an Figures 7 and 8 5.0. RECOMMENDATIONS Based on the results of this and previous investigations, AGE recommends • Continued quarterly monitoring of the ground water monitoring network • Preparation of a work plan for interim remediation of petroleum hydrocarbon-impacted ground water at the site and vertical definition of the dissolved hydrocarbons and additives Advanced GeoEnvrronmental,Inc.