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I r f ' 03 September 2004 AGE-NC Project No 97-0312 ' Page 4of5 samples are summarized in Tables 4 and 5 Figures 4 and 5 illustrate the areal extent of TPH-g,TPH- ' d-and 1,2-DCA-impacted ground water GeoTracker confirmation pages ofthe submitted laboratory electronic deliverable format (EDF) files are Included In Appendix C 4.0. DISCUSSION AND CONCLUSIONS 1I t Based upon data collected from the site, AGE concludes • Ground water elevation decreased approximately 2 9 feet at the site between the March 2004 ' and June 2004 monitoring events The Inferred ground water flow direction was generally, toward the northeast The ground water gradient was approximately 0 001,ft/ft across the site ' During the June 2004 monitoring event, TPH-g was detected in the water sample collected from monitoring well UST-5 MTBE was detected In the sample collected from well UST-6 ' 1,2-DCA was detected In samples collected from wells UST-5 and UST-6 The maximum concentration of 1,2-DCA was detected In the sample collected from well UST-5 at 400µg/l The detected concentrations were above the DHS' Maximum Contaminant Level(MCL)of lie 0 5 µg/1 • PCE was detected in the sample collected from well UST-7 ' • The reported concentrations and ldteral extent of analytes of concern have remained relatively stable during the past three years of monitoring Based on the analytical results of the ground water sample collected from UST-7, the vertical extent of petroleum x hydrocarbon-Impacted ground water at the site appears to be limited to the uppermost hydrogeologic zone The source of the PCE detected In UST-7 Is unknown to AGE and may ' be from'an off-site,source ' S.O. RECOMMENDATIONS Based on the results of this and previous quarterly ground Iwater monitoring events, AGE recommends continued monitoring of the on-site monitoring and domestic wells I ' Advanced GeoEnvironmental,Inc