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05 October 2007 AGE-NC ProjectNo.07-1537 ' Page 7 of 8 • In general,the subsurface soil consisted dominantly of fine-grained soil(dark yellow-orange ' brown to dark yellow-brown clay, silty clay, silt and clayey silt); sand and silty sand was identified at approximate depths of from 21 to 25 feet bsg, and 99 to 105 feet bsg. ' • Contaminants of concern(COCs)were detected in all soil samples collected from the CPT-1 location except sample CPT1-80. TPH-g was detected in the soil sample collected from CPT 1-15 at a concentration of 710 mg/kg;the BTEX compounds toluene,ethylbenzene and ' xylenes were detected in soil samples CPT1-15, CPT1-67, and CPT1-90 at maximum concentrations of 1.7 mg/kg(toluene),9.0 mg/kg(ethylbenzene),and 91 mg/kg(xylenes)in CPT1-15;and MTBE was detected in soil samples CPT1-67 and CPT1-90 at concentrations of 0.030 mg/kg, and 0.010 mg/kg, respectively. • COCs were not detected in soil samples collected from monitoring-well pilot borings MW4, ' MW5, and MW6. • COCs were detected in all grab ground water samples collected from the CPT-1 location;the ' maximum concentrations were detected in ground-water sample CPT1-90 at 1200 µg/l TPH-g, 25 µg/1 benzene, 140 µg/l toluene, 34 µg/1 ethylbenzene, 193 µg/l xylenes and 150 µg/l MTBE. ' • Except for TPH-g, which does not appear to extend below 55 feet bsg in Boring B-1, the vertical extent of petroleum hydrocarbons- and MTBE-impacted soil is not defined. The ' lateral extent of petroleum impacted soil appears to be defined to the northeast, east, and southeast of the former UST area by monitoring wells MW-4 through MW-6, and west by MW-1; it is not defined to the north and south. ' • The lateral and vertical extent of petroleum hydrocarbons- and MTBE-impacted ground water is not defined. 1 5.0. RECOMMENDATIONS Based on the findings of the environmental activities recounted in this report, AGE recommends: ' • Continued quarterly ground water monitoring at the site.The third quarter 2007 ground water monitoring event occurred on 06 July 2007.The fourth quarter 2007 groundwater monitoring event is scheduled for 09 October 2007. ' • Preparation of a work plan for additional soil borings and monitoring wells to assess the vertical extent of petroleum hydrocarbon-impacted soil and ground water, as well as the ' lateral extent of petroleum hydrocarbon-impacted soil and ground water to the north and south of the former UST area. ' Advanced GeoEvironmental,Inc.