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T 22 April 2002 AGE-NC Project No 98-0448 Page 6 of 8 ' Q = extraction flow rate (M3/hr) t= operational period, in hours Between 01 October 2001 and 31 December 2001 (fourth quarter 2001), the SVE unit operated ' approximately 2,272 hours (Table 7) 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 During the fourth quarter 2001, the mass of hydrocarbons extracted from the SVE system was ' calculated to be approximately 127 1 pounds, or equivalent to a volume of 20 4 gallons of gasoline extracted A plot of the cumulative volume (gallons) of hydrocarbons extracted to date is in Appendix E Added to the estimated 144 gallons of hydrocarbons extracted from the SVE system " ' since 16 April 2001,the total volume of hydrocarbons extracted to date is estimated at 164 4 gallons The mass/volume calculations for extracted hydrocarbons are included with Appendix F 5.0. DISCUSSION AND CONCLUSIONS The implications from the November 2001 ground water monitoring event are as follows a Ground water flow direction at the site was generally toward the south-southwest at a gradient of 0 02 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 151 feet between July 2001 and " November 2001 is probably due to seasonal fluctuation rThe ground water elevation at the site was generally within the screened intervals of wells MW-1, MW-2, MW-3, MW-4A, MW-5, MW-6, MW-7 and MW-8 and should be ' representative of shallow ground water conditions,however well MW-4B is"drowned"with water approximately 25 feet over the screen and yields a sample more representative of deeper ground water conditions ' Ground water elevation data collected on 01 November 2001 was inconclusive regarding potential water mounding due to air sparging at the site ' The elevated concentrations of petroleum hydrocarbons detected in samples collected from wells MW-1,MW-2;MW-4A and 1\4W-4B indicate that these wells are within the dissolved petroleum hydrocarbon"core area" of the plume (Figures 4) ' Advanced GeoEnvironmental,Inc a ,