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1 ' 26 September 2002 i AGE-NC Project No 95-0173 ' Page 6 of 8 Q = extraction flow rate (m3/hr) ' t = operational period, in hours I Between 11 March 2002 and 11 June 2002, the SVE unit operated a total of 2,208 hours (Table 6) The average analytical results (approximately 428 µg/l) of the SVE air flow samples (Table 5), average flow rates (approximately 98 cfm, Table 6) and the operational period (2,208 hours) were ' used to calculate the approximate mass of extracted gasoline during this period During the March,April,May and June 2002 period,the mass of hydrocarbons extracted by the SVE ' system was calculated to be approximately 347 pounds, or equivalent to a volume of 55 4 gallons of gasoline Added to the estimated 1,225 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 ' 1,280 gallons(Table 7) A plot of the cumulative volume(gallons)of hydrocarbons extracted to date is included with Appendix E The mass/volume calculations for extracted hydrocarbons are included with Appendix F 5.0. CONCLUSIONS ' The implications from the June 2002 ground water monitoring event are as follows I • Ground water flow direction at the site was generally toward the northeast at a gradient of 0 004 ft/ft or less Due to the 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 0 29 feet between March 2002 and I June 2002 is probably due to seasonal fluctuation • Ground water at the site was between 3 feet and 70 feet above the screen intervals(drowned) of wells MW-1 through MW-4, AW-1A, AW-1B, AW-2A and AW-2B and may not yield samples fully representative of shallowest ground water conditions The ground water elevation appeared to be within or near the screen intervals of wells MW-5 through MW-12 and should he representative of shallowest ground water conditions • Ground water elevation data collected on 20 June 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) I Advanced GeoEnvironmental,Inc I