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I26 September 2002 AGE-NC Project No 98-0448 IPage 5 of 8 It= operational period, in hours Between 11 March 2002 and 11 June 2002,the SVE unit continuously operated approximately 2,208 I hours The average of analytical results between SVE air flow sampling events (Table 5), average SVE air flow rates, (Table 6) and the operational period were used to calculate the approximate volume and mass of extracted gasoline during these periods IBetween the 11 March, 23 April, 13 May and 11 June 2002 air monitoring events, the mass of hydrocarbons extracted from the SVE system was calculated to be approximately 69 pounds, or I equivalent to a volume of approximately 11 gallons of gasoline extracted A plot of the cumulative volume (gallons) of hydrocarbons extracted to date is in Appendix E Added to the estimated 173 gallons of hydrocarbons extracted from the SVE system since 16 Apnl 2001, the total volume of hydrocarbons extracted to date is approximately 185 gallons The mass/volume calculations for extracted hydrocarbons are included with Appendix F I Y 5.0. DISCUSSION AND CONCLUSIONS IThe implications from the May 2002 ground water monitoring event are as follows o Ground water flow direction at the site was generally toward the south-southwest at a gradient of 0 01 ft/ft or less Due to the low gradient at the site, slight variations in ground water measurements or changes ofrecharge/discharge of the local ground water could greatly modify the inferred ground water flow direction • The decrease of ground water elevation of approximately 0 20 feet between February 2002 I and May 2002 is probably due to seasonal fluctuation • The ground water elevations at the site were within the screened Intervals of wells MW-4A, MW-5,MW-6,MW-7 and MW-8 and slightly above the screened intervals of wells MW-1, I MW-2 and MW-3, ground water samples from these wells should be representative of shallow ground water conditions Well MW-4B was "drowned", with water approximately 25 feet above the screen, and should yield a sample more representative of deeper ground ' water conditions • Ground water elevation data collected on 30 May 2002 was inconclusive regarding potential Iwater mounding due to air sparging at the site Y • The elevated concentrations of petroleum hydrocarbons detected in samples collected from wells MW-2, MW-4A and MW-4B indicate that these wells are within the dissolved petroleum hydrocarbon"core area" of the plume (Figures 4) IAdvanced GeoEnv3 ron mental,Inc