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s k'q KLEINFELDER 6 CONCLUSIONS AND RECOMMENDATIONS On August 12, 2002, 12 monitoring wells were sounded for depth to groundwater, 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: 1. Groundwater flow direction at the site is estimated to be towards the south at approximately 0.0002 ft./ft. This is consistent with the historical groundwater data collected at the site. 2. Based on the results of the groundwater sampling it appears that the groundwater quality has remained relatively consistent with the first two sampling events this year. The results showed no. TPH-g detected in monitoring wells MW-DIS-9, MW- DIS-11s, MW-DIS-11d, MW-DIS-12, MW-DIS-13, MW-DIS-14, and MW-DIS- 14d. However, TPH-g was detected in the remaining groundwater samples collected from MW-DIS-1, MW-DIS-2, NP-1-70', NP-1-80', and NP-1-90with concentrations ranging from 100 ug/l in MW-DIS-2 to 170,000 ug/l in NP-1-801 . 1,2-DCA was detected in seven of the twelve groundwater samples analyzed ranging from 0.90 ug/1 (1\4W-DIS-12) to 1,500 ug/I (NP-1-80'). This sampling event marks the first time 1,2-DCA was detected in MW-DIS-12. The remaining five groundwater samples showed non-detect concentrations of 1,2-DCA above the laboratory reporting limit (ND < 0.5 ugll). The PMCL for 1,2-DCA is 5 ug/l. The detected concentration of 1,2-DCA in MW-DIS-12 and MW-DIS-14s did not exceed the PMCL for 1,2-DCA in groundwater, however the remaining detected concentrations did exceed the PMCL for 1,2-DCA. EDB was detected in one groundwater samples analyzed (NP-1-80'). The detected concentration of EDB was 1,100 ug/l. The remaining eleven groundwater samples showed non-detect concentrations.of EDB above the laboratory reporting limit (ND <0.5 ug/1). The PMCL for EDB is 0.05 ug/l. Benzene was detected in five groundwater samples. The concentration of benzene was shown to remain consistent with the previous sampling events. The remaining seven groundwater samples showed non-detect concentrations of benzene above the laboratory reporting limit (ND < 0.50 [tg/1). The Primary Maximum Contaminant Level (PMCL) for benzene is 1 ug/l, The laboratory reporting limit for benzene (0.50 µg/1) is below the PMCL for benzene in water in monitoring well MW-DIS- I Is, however, exceeds the PMCL for benzene in MW-DIS-1, NP-1-70', 80', and 90'. Toluene was detected in four of the twelve groundwater samples collected. The detected concentrations ranged from 1,000 ug/I (MW-DIS-1) to 44,000 ug/1 (NP-1- 12280.MON/ST02R519 Page 11 of 14 ©2002,Kleinfelder,Inc September 19,2002