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1 ' 20 December 2004 • AGE-NC Project No 98-0511 Page 3 of 4 well MW-4 to 1 88 feet below MSL in well MW-7 Ground water at the site was Inferred to flow in a southwest-plunging trough (Figure 3) under an average hydraulic gradient of approximately 0 004 foot/foot (ft/ft) 1 32 ANALYTICAL RESULTS OF GROUND WATER SAMPLES TPH-g was detected in ground water samples collected from monitoring wells MW-1 and MW-5 at concentrations of 970 micrograms per liter(µg/l) and 200 µg/l,respectively Benzene was detected I in samples MW-1 and MW-5 at concentrations of 29 µg/1 and 3 1 µg/1,respectively Maps showing the approximate distributions of dissolved TPH-g and benzene at the site are Illustrated on Figures 4 and 5, respectively Toluene, ethylbenzene, and total xylenes were detected in sample MW-1 at concentrations of 7 8 µg/1, 100µg/1 and 237 µg/l,respectively Ethylbenzene was detected in sample MW-5 at a concentration of 11 µg/1 TPH-g and BTEX compounds were not detected in samples collected from wells MW-2 through MW-4 and MW-6 through MW-8 Utilizing EPA Method 8260B,MTBE was detected in the ground water samples collected from wells . MW-1, MW-3, and MW-5 at concentrations of 3 4 µg/l, 3 9 µg/1, and 40 µg/1, respectively No other constituents of concern were detected at or above laboratory reporting limits Analytical I results of ground water samples are summarized in Tables 2 and 3 The Inferred lateral distributions of TPH-g and benzene are Illustrated on Figures 4 and 5,respectively Copies of the laboratory report (CTEL Prod ect No CT214-0409143),quality assurance/quality control report,and chain of custody I forms are provided in Appendix C Documents confirming the upload of laboratory electronic deliverable format (EDF) files and depth to water measurements to GeoTracker are provided in Appendix D I 4 0. SUMMARY AND CONCLUSIONS Based upon data collected from the site during the September 2004 investigation, AGE concludes the following - Ground water elevations in the monitored area averaged 1 57 feet below MSL with the ground water elevation decreasing approximately 3 34 feet since the previous quarter IGround water at the site was inferred to flow in a southwest-plunging trough under an average hydraulic gradient of approximately 0 004 ft/ft I - TPH-g and BTEX compounds were detected in ground water sample MW-1 at • concentrations of 970 µg/1 TPH-g,29 µg/1 benzene,7 8 µg/1 toluene, 100 µg/1 ethylbenzene, and 247 µg/1 total xylenes, in addition, benzene and ethylbenzene were detected in sample Advanced GeoEnvlronmental,Inc