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k9 KLEINFELDER 6 CONCLUSIONS AND RECOMMENDATIONS On February 17, 18 and 19, 2004, nine monitoring wells and 3 piezometers were purged and sampled. Water samples obtained from each location were submitted for chemical analysis. Based on the data obtained during our assessment, the following conclusions and recommendations have been formulated: I. Groundwater flow direction at the site is calculated to be towards the southeast with a gradient of approximately 0,001 ft/ft. A localized groundwater mound was noted near the source are.in SVE-N and SVE-S and a small groundwater depression was noted near MW-1 and MW-DIS-11s. The localized depression and mounds appear to be a direct result of the remedial activities in the area. 2. Based on the laboratory results of the groundwater sampling, the detected concentrations of TPH-g in the source area samples all showed increases in the concentration versus the previous date analyzed. This quarter marks the first time TPH-g has been detected in the downgradient well MW-11s since May 2002. Xylene concentrations in the source area wells and piezometers tested this quarter showed increases over the previous quarterly results. The concentration of ethyl- benzene in 4 of the 5 source area samples increased this quarter. Only 1 source area piezometers showed an increase in the benzene concentration (NPI-70') whereas the remaining 4 samples collected from the source area showed decreases in the concentration of benzene. The toluene concentration in MW-2 increased this quarter while the other 4 source area samples decreased or remained unchanged from the previous sample date. 1,2-DCA concentrations increased in 2 of the 5 source area samples (MW-i and NPI- 70% decreases in 2 samples and remained unchanged in 1 sample compared to the previous sample date in each well. EBD increased in only 1 sample (NP1-80'), decreased in 1 sample and remained the same in 3 samples. The 7 downgradient well samples showed only one increase of TPH-g (MW-1 Is) as noted.above. There were no detected concentrations of any of the BTEX compounds in any of the downgradient wells this quarter. Additionally, there was no EDB concentrations detected at or above the laboratory reporting limit. TBA concentrations in each of the downgradient samples analyzed decreased to non- detectable concentrations compared to the results from last quarter. The concentrations of 1,2-DCA detected in the downgradient wells increased in 2 of the 7 samples (MW-11s and MW-14s), remained non-detect in 4 samples, and decreased in I sample (MW-15). Only the sample collected from MW-15 was analyzed for the fuel oxygenates MTBE, DIPE, ETBE, and TAME this quarter and showed non- detectable results of each compound. t2280.MON/ST04R397 Page 11 of 13 ®2004,Klcinfelder,Inc May 11,2004