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' 26 April 2002 AGE-NC Project No 95-0173 ' Page 6 of 8 period(1,822 hours)were used to calculate the approximate mass of extracted gasoline during this ' period ' During the fourth quarter 2001, the mass of hydrocarbons extracted by the SVE system was calculated to be approximately 672 pounds, or equivalent to a volume of 107 gallons of gasoline Added to the estimated 1,048 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 1,155 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 December 2001 ground water monitoring event are as follows • Ground water flow direction at the site was generally toward the northeast at a gradient of 0 003 ft/ft or less Due to the low gradient at the site, slight variations in ground water rmeasurements 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 07 feet between September 2001 and December 2001 is probably due to seasonal fluctuation ' • Ground water elevation data collected on 19 December 2001 does not suggest ground water mounding is occurring due to air sparging at the site • Ground water at the site is between 2 feet and 70 feet above the screen Intervals (drowned) of wells MW-1 through MW-4, AW-lA through AW-2B and MW-13 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 be representative of shallowest ground water conditions • 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 and 5) ' • The highest dissolved petroleum hydrocarbons were detected in the area of well AW-2,with increasing depth,the dissolved plume apparently grades from higher concentrations to lower concentrations • A moderate to substantial decrease in concentrations of dissolved TPH-g and BTEX were . quantified in ground water samples collected from wells MW-2, MW-6, AW-lA, AW-1B ' Advanced GcoEnvirenmcntal,Inc I