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k k k � 15 June 2004 i AGE-NC Project No. 95-0167 Page 3 of 4 3.2. LABORATORY RESULTS OF GROUND WATER SAMPLES TPH-g was detected in the water samples collected from monitoring well MW-1 at a concentration ; of 8,800 micrograms per liter(µg11). E� ! BTEX compounds were detected in the water samples collected from monitoring well MW-1at I concentrations of 2,500 µg11 of benzene, 1,600 pg/l of toluene, 420 µg/l of ethylbenzene and 1,950 µg/l of xylenes. MTBE was detected in sample MW-1 at a concentration of 22 µg/l. 1,2-DCA was detected n sample MW-1 at a concentration of 7.1 µg11. M No other fuel additives were detected at or above laboratory detection levels in the ground water samples. No other samples hade detectable concentrations of dissolved hydrocarbons. Analytical results of ground water samples collected during the December 2003 monitoring event s' are summarized on Tables 2 and 3. The laboratory report (CTEL Project No: CT214-0312037), QA/QC report and chain-of-custody form are included in Appendix C.Figure 4 depicts the estimated i lateral distributions of dissolved TPH-g and benzene in ground water. 4.0. SUMMARY AND CONCLUSIONS ' Data collected at the site indicates that: } • The ground water flow direction during this monitoring event was toward the west-northwest i at an average gradient of 0.009 feet/feet. Ground water flow at the site has historically been , towards the northwest. Ground water flow direction is not well defined south of the former UST area; • Relatively high concentrations of TPH-g and BTEX occur in ground water in the area of i monitoring well MW-1; TPH-g and BTEX concentrations were not detected this quarter in the samples collected from well MW-2. This is the first time in the past 4 sampling events TPH and BTEX compounds were not detected in well MW-2 i MTBE was present in monitoring well MW-1 at a concentration of 22µg/l and 1,2-DCA was fj detected for the first time in well MW-1 at a concentration of 7.1 µg11. • The contaminant plume appeared to be confined to the general area of the former UST location at well MW-1. Petroleum hydrocarbons were not detected in perimeter wells' In addition,petroleum hydrocarbons were not detected in a grab ground water sample collected and analyzed in April 1997 from soil boring P4, south of the former UST location. it Advanced GeoEnvironmental,Inc. a 1 J