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I lie 03 October 2000 AGE-NC Project No 97-0326 IPage 4 of 5 ' S.O. SUMMARY AND CONCLUSIONS Based upon data collected from the site, AGE concludes the following • Petroleum hydrocarbons were detected in B5 soil samples collected at depths of 45 and 50 feet bsg,indicating that this mterval has been impacted by hydrocarbons Field observations ' also indicated the presence of hydrocarbon vapor in soil samples collected, beginning at depths ranging from 30 feet to 60 feet bsg,peaking at 50 feet bsg The initial site assessment report suggests that the impacted interval may be a "smear zone" as a result of fluctuation ' in ground water elevation of the perched ground water "aquifer", vertically spreading hydrocarbons over that interval The source of hydrocarbons has not been determined AGE ' has been unformed that the current tanks were not the original tanks on the property It is possible that the location of the original tanks, which is currently unknown, or the fuel dispensers could be the source area(s) of the hydrocarbon impact I • Petroleum hydrocarbons were not detected in the samples collected from 45 to 70 feet in boring B6, however, field screening detected the presence of hydrocarbon vapor in soil samples collected from 45 feet to 65 feet bsg, peaking at 50 feet bsg I • Relatively low concentrations of BTEX were detected in samples containing petroleum hydrocarbons, possibly indicating that the release is not recent • Boring B5 encountered saturated conditions in a sand unit at a depth of 40 feet bsg and there appears to be a hard,moist silty clay at 45 and 50 feet bsg, similar to boring B2(10 feet south ' of MW1) reported in the original preliminary report dated 08 August 1997 Ground water occurs at a depth of 31 feet bsg in the monitoring wells on the property • TPH-g and BTEX were detected in grab water samples B5-70 and B6-70, MTBE was detected in B6-70 The data suggest that the vertical extent of impacted ground water is as deep or deeper than the depths of the present wells on the property 6.0. RECOMMENDATIONS ' Based upon data collected from the site, AGE recommends the following I Advance one CPT boring on site to assess the vertical extent of impacted ground water, In- as-far as the vertical as well as horizontal extent of impacted soil and ground water have not yet been fully defined Grab water samples collected at 70 feet bsg during this latest soil boring program contained petroleum hydrocarbons Prior to installation of additional • monitoring wells,the vertical extent of the impacted zone on the site should be determined At least one deep soil boring should be advanced in the area where the TPH concentration I Advanced GeoEnviranmentai,Inc.