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• 19 July 1995 AGE-NC-95-0109 Page 7 of 8 and EW-1 at concentrations of 0 73 ppb, 2 9 ppb, 15 ppb, 3 3 ppb, 5 1 ppb and 1 8 ppb, respectively The concentrations of both compounds in the wells are similar to previous monitoring results Chloroethane, tetrachloroethene and other volatile halocarbons were not detected in any of the water samples analyzed The analytical results are summarized in Table 6 The laboratory report and chain- of-custody form are included in Appendix D 5.0, CONCLUSIONS AND RECOMMENDATIONS 5 1 HYDROCARBON-IMPACTED GROUND WATER Ground water elevation has risen about 1 foot throughout the site since March 1995 (see Table 4) The change of ground water elevation is assumed to be the result of a seasonal rise in ground water elevation The ground water flow direction continues to be to the south-southwest Hydrocarbon concentrations in ground water samples continue to fluctuate widely at the site . However, the overall average concentrations of hydrocarbons at the site have decreased slightly since the March 1995 sampling Samples from MW-7,MW-10, MW-11, and MW 13 continue to indicate that the hydrocarbon plume has not migrated beyond the known plume boundaries, although TPH-g was detected at just above the reporting limit in MW-10 at 52 ppb during the rune 1995 sampling Concentrations of hydrocarbons in wells MW-6 and MW-9, on the perimeter of the plume, were reduced from the previous monitoring event in March 1995 Current microbiological data indicates continued significant biodegredational activity in the ground water Vapor readings from monitoring wells support this correlation 5 2 HYDROCARBON-IMPACTED SOII, Concentrations of petroleum hydrocarbons in the soil continue to show a decrease in most areas Analytical results of soil samples collected form borings near the southern end of the impacted soil plume(borings P 12 and P 13) indicate that petroleum hydrocarbon concentrations in the soil are well below 125 ppm and in most areas, below 20 ppm As during the March 1995 monitoring, this indicates a decrease in hydrocarbons of as much as 98% from baseline concentrations Near the north end of the site, petroleum hydrocarbon concentrations were present at concentrations . up to 1,822 ppm However, overall petroleum hydrocarbon concentrations at the-sate indicate a