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' O1 May 2006 • AGE-NC Project No 99-0657 ' Page 3 of 4 ' 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES TPH-g was detected in the ground water samples collected from wells MWA, MW-2, MW-4, and ' MW-6 at concentrations ranging from 100 micrograms per liter (µg/l, MW-6) to 13,000 µg/l (MW-1) BTEX compounds were detected in wells MW-1, MW-2, and MW-4 at the following maximum concentrations in well MW-1 1,500 µg/l benzene, 1,700 µg/l toluene, 230 Vg/l ' ethylbenzene, and 1,860 µg/1 xylenes MTBE was detected in water samples collected from wells MW-1, MW-2, MW-4, and MW-6 at ' concentrations ranging from 10 µg/1 (MW-4) to 710 µg/l (MW-1) 1,2-DCA was detected in water samples collected from wells MW-1, MW-4, and MW-6 at concentrations of 38 pg/l, 17 pg/l, and 5 8 µg/l, respectively TAME was detected in wells MW-1 and MW-2 at concentrations of 8 5 µgh ' and 22 µg/1, respectively No target analytes were detected in the samples collected from vertical profile ground water ' monitoring wells MW-10 and MW-11 Analytical results of the groundwater samples collected in February 2006 are summarized in Table 2 The laboratory report (CTEL Project No CT214- 0602055), quality assurance/quality control (QA/QC) reports, and chain of custody forms are included in Appendix C 4.0. SUMMARY AND CONCLUSIONS ' The following conclusions were drawn from the results of this investigation • At the time of the February 2006 sampling event, depths to ground water ranged from ' 34 74 feet to 38 04 feet below the tops of the well casings Ground water elevation at the site averaged approximately 7 9 feet above MSL,indicating an Increase in average ground water elevation of approximately 1 8 feet since the last monitoring event in November 2005 ' Ground water flow was inferred to be flowing toward the south-southwest under calculated hydraulic gradients ranging from approximately 0 003 ft/ft to 0 006 ft/ft This flow direction ' remains consistent with the previous monitoring events • The highest concentrations of dissolved hydrocarbons generally occurred in monitoring wells MW-1 and MW-4, which are located at or down-gradient of the UST area Concentration ' maps depicting the approximate distribution of dissolved TPH-g, benzene, MTBE, and 1,2-DCA are Illustrated on Figures 4 through 7, respectively ' Concentrations of dissolved TPH-g Increased this quarter in monitoring wells MW-1 and MW-2, TPH-g remained below laboratory detection limits in well MW-5 for the second consecutive quarter, but Increased to 100 µg/l in well MW-6 Concentrations of benzene Advanced GeoEnvironmental,Inc 1