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1J � 20 April 1995 AGE-NC-95-0109 Page 6 of 8 in Appendix D Historical TPH-g concentrations in wells MW-6 through MW-14 and EW-1 are also shown graphically in Figures 4 through 13 Please note that full scale inoculation was completed on day 1,500 Between September and December 1994, TPH-g and BTESX concentrations decreased in six of the nine wells at the site EDB was reported at a concentration of 46 ppb in MW-14 1,2-Dicliloroethane was detected in samples from MW-8, MW-9, MW-13, MW-14 and EW-1 at concentrations of 2 8 ppb, 26 ppb, 2 4 ppb, 60 ppb and 0 87 ppb, respectively The concentrations of both compounds in the wells are similar to previous monitoring results Chloroethane was detected again at a trace concentration of 1 I ppb in MW-9 However, this compound was not detected in MW-14 Tetrachloroethene and other volatile lialocaibons were not detected in any of the `eater samples analyzed The analytical results are summarized in Table 6 The laboratory results and charir-of- custody are included in Appendix D 50 CONCLUSIONS AND RECOMMENDATIONS 51 HYDROCARBON-IMPACTED GROUNDWATER Ground water elevation has risen about 2 feet throughout the site since December 1994 (see Table 3) Tire change of ground water elevation is assumed to be the direct result of excessive precipitation from the most recent wet season The ground %eater flow direction continues to be to the south-southwest Historically, hydrocarbon concentrations in ground water samples have fluctuated widely at the site However, towards the end of 1994 concentrations appear to stabilize and, during the December 1994 sampling, were significantly reduced in most wells A greater- variance was observed during the March 1995 monitoring However, the average concentrations decreased over the site Samples from MW-7, MW-10, MW-11, and MVV-13 seem to indicate that the hydrocarbon plume has not rnigiated beyond the known plume boundaries Concentrations of hydrocarbons in wells MW-6 and MW-9, on the perimeter of the plume, were also significantly reduced from the previous monitoring event in December 1994 Although current microbiological data is not available, field measurements of dissolved