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30 September 2005 . AGE-NC Project No 99-0657 Page 7 of 8 • Petroleum hydrocarbons were detected in soil samples collected between 25 feet and 60 feet bsg and from 90 feet to 110 feet bsg in boring B-1 The lateral extent of petroleum hydrocarbon-Impacted soil is defined,the vertical extent of petroleum hydrocarbon-impacted soil is defined Petroleum hydrocarbon-Impacted soil does not extend beyond 120 feet bsg Figure 3 depicts the approximate extent of impacted soil • The ground water elevation averaged approximately 4 64 feet above MSL Ground water is inferred to be flowing toward the southwest under an average ground water gradient of 0 004 ft/ft which is consistent with previous monitoring events I0 The highest concentrations of dissolved hydrocarbons occurred in monitoring wells MW-1, MW-2, and MW-4, which are located at or down-gradient of the UST area Concentration maps depicting the approximate distribution of dissolved TPH-g and MTBE are presented ' as Figures 5 and 6, respectively • Concentrations of dissolved TPH-g increased this quarter in monitoring wells MW-3, MW-4 ' and MW-6,TPH-g was detected again in perimeter well MW-5 and for the first time in two sampling events in well MW-6 Concentrations of benzene increased in wells MW-1 through MW-5 since the previous monitoring event MTBE concentrations increased in wells MW-1, I MW-2, MW-3 and MW-6 and decreased slightly in well MW-4 1,2-DCA concentrations increased in wells MW-1,MW-2,MW-4 and MW-6 and was detected in newly installed well MW-9 ' 0 The lateral extent of petroleum hydrocarbon contamination in ground water has been defined to the east, south and north (CPT-1) of the UST area The lateral extent in not fully defined I to the west of the UST area beyond wells MW-5 and MW-6 • The vertical extent of petroleum hydrocarbon-impacted ground water is defined off-site in the area of soil boring CPT-1 However, the vertical extent is undefined in the area of and down-gradient from the former UST area(CPT-2 and CPT-3) 5.0. RECOMMENDATIONS Based on the findings of this investigation,AGE recommends,continuation of the quarterly ground water monitoring program, as required by the EHD Additional ground water monitoring wells were installed at the site in April 2005 Findings will be submitted in the second quarter 2005 report for the site AGE anticipates the second quarter report will be submitted shortly following the first quarter 2005 report IAdvanced GeoEnvironmcatal,Inc I