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27 June 2002 <br /> r� AGE-NC Project No 98-0448 <br />' Page 6 of 8 <br />' Q = extraction flow rate (M3/hr) <br /> t= operational period, in hours <br /> I Between 01 January 2002 and 31 March 2002 (first quarter 2002), the SVE unit continuously <br /> operated approximately 2,160 hours The average of analytical results between SVE air flow <br /> sampling events (Table 5), average SVE air flow rates, (Table 6) and the operational period were <br /> Iused to calculate the approximate volume and mass of extracted gasoline during these periods , <br /> Between 10 January, 22 February and 11 March 2002, the mass of hydrocarbons extracted from the <br /> I SVE system was calculated to be approximately 56 63 pounds, or equivalent to an approximate <br /> volume of 9 05 gallons of gasoline extracted A plot of the cumulative volume (gallons) of <br /> hydrocarbons extracted to date is in Appendix E Added to the estimated 164 gallons of <br /> I hydrocarbons extracted from the SVE system since 16 April 2001, the total volume of hydrocarbons <br /> extracted to date is estimated at 173 5 gallons The mass/volume calculations for extracted ` <br /> hydrocarbons are included with Appendix F <br /> I • 5.0. DISCUSSION AND CONCLUSIONS <br /> The implications from the February 2002 ground water monitoring event are as follows <br /> I • Ground water flow direction at the site was generally toward the southwest at a gradient of <br /> 0 02 ft/ft or less Due to the low gradient at the site, slight variations in ground water <br /> measurements or changes of recharge/discharge of the local ground water could greatly <br /> I modify the inferred ground water flow direction <br /> • The increase of ground water elevation of approximately 1 79 feet between November 2001 <br /> and February 2002 is probably due to seasonal fluctuation <br /> • The ground water elevation at the site was generally within the screened intervals of wells <br /> I MW-1, MW-2, MW-3, MW-4A, MW-5, MW-6, MW-7 and MW-8 and should be <br /> representative of shallow ground water conditions,however well MW-4B is "drowned"with <br /> water approximately 26 feet over the screen and yields a sample more representative of <br /> Ideeper ground water conditions <br /> • Ground water elevation data collected on 12 February 2002 was inconclusive regarding <br /> potential water mounding due to air sparging at the site <br /> • The elevated concentrations of petroleum hydrocarbons detected in samples collected from <br /> wells MW-1, MW-2,MW-4A and MW-4B indicate that these wells are within the dissolved <br /> petroleum hydrocarbon "core area" of the plume (Figures 4) <br /> Advanced GeoEnvironmental,Inc <br />