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' 28 May 2003 AGE-NC Project No 95-0173 ' Page 7 of 8 ' ground water elevation appeared to be within or near the screen intervals of all other wells at the site and should be representative of shallowest ground water conditions • Ground water elevation data collected on 30 December 2002 does not suggest ground water mounding is occurring due to air sparging at the site • The elevated concentrations of petroleum hydrocarbons detected in samples collected from ' wells MW-3, MW-4, AW-1 and AW-2 indicate that these wells are within the dissolved petroleum hydrocarbon "core area" of the plume (Figures 4) • The highest dissolved petroleum hydrocarbons were detected in the area of well AW-2,there does not appear to be any significant quarterly concentration trends in the dissolved plume located between AW-2A (40 to 45 feet bsg) and AW-2B (60 to 70 feet bsg) • Compared to the previous quarter,moderate decreases in concentrations of dissolved TPH-g and BTEX were quantified in ground water samples collected from wells MW-3 and AW-1B (Table3) while a moderate increase was reported from well AW-1 A • Previous and current laboratory results of ground water samples suggest that there is a minor MTBE- and 1,2-DCA-impact to ground water in the areas of wells MW-2 through MW-5 (Tables 3 and 4) I Based on SVE remediation data collected between 11 June and 26 September 2002,AGE concludes • The average SVE inlet vapor concentration was approximately 1,620 µg/l, the average SVE inlet flow rate was approximately 98 cubic feet per minute (Table 6) • The volume of hydrocarbons extracted by the SVE system was calculated to be approximately 200 gallons of petroleum hydrocarbons(Appendix F) during the September, IOctober, November and December monitoring periods (Table 7) • Since initiation of the SVE system,the total volume of petroleum hydrocarbons extracted is estimated to be approximately 1,548 gallons (Table 7) • No general concentration trends were evident in the PID field measurements, however, laboratory analytical results were generally higher compared to the July, August and September monitoring periods I � lie Advanced GeoEnvironmental,Inc