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' 01 October 2004 AGE-NC Protect No 95-0173 ' Page 7of10 ' Q = extraction flow rate (m3/hr) t =operational period, in hours Between 24 March 2004 and 22 June 2004 (second quarter 2004), the SVE unit operated a total of 2,160 hours (Table 6) The average analytical results (approximately 93 µg/1) of the influent SVE air flow samples(Table 5),average flow rates(approximately 74 scfm,Table 6) and the operational ' period(2,160 hours) were used to calculate the approximate mass of extracted gasoline during this period ' During the second quarter 2004 operational period,the mass of hydrocarbons extracted by the SVE system was calculated to be approximately 56 pounds, or equivalent to an approximate volume of 9 gallons of gasoline Added to the estimated 1,929 gallons of hydrocarbons extracted from the SVE ' system since 11 April 2000(start-up),the total volume of hydrocarbons extracted to date is estimated at 1,938 gallons (Table 7) A plot of the cumulative volume (gallons) of hydrocarbons extracted to date is included in Appendix G The volume/mass calculations for extracted hydrocarbons are fincluded as Appendix H 4 0 CONCLUSIONS IThe implications from the 06 July 2004 ground water monitoring event are as follows • Ground water flow direction at the site was generally oriented east-northeast across the site ' with a gradient as great as 0 005 ft/ft Due to the generally low gradient at the site, slight variations in ground water measurements or changes of recharge/discharge of the local ground water could greatly modify ground water flow direction ' • The decrease of ground water elevation of approximately 1 54 feet between the 19 March 2004 and the 06 July 2004 monitoring events is probably due to seasonal fluctuation ' • Ground water at the site was significantly above (drowned) the screen intervals of wells AW-1 (A and B), AW-2 (A and B) and MW-13 (A, B and C) and yield samples more representative of deeper ground water conditions The 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 06 July 2004 does not suggest that ground water mounding may have occurred due to the on-going IAS activities • The elevated concentrations of petroleum hydrocarbons detected in samples collected from wells MW-4(screened 30 to 50 feet),AW-lA(screened 39 to 44 feet)and AW-1B(screened 50 to 60 feet bsg) indicate that these wells are within the remaining dissolved petroleum Ihydrocarbon "core area" of the plume (Figure 4) Advanced GeoEnvsronmental,Inc