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' 26 February 2001 AGE-NC Project No 95-0173 ' Page 6of8 ' samples (Table 3), average flow rates (approximately 95 cfm, Table 5) and the operational period were used to calculate the approximate mass of extracted gasoline during these periods During the 0 quarter 200a ass of hydrocarbons extracted from the SVE system was calculated to be approximat 1,268 poun s, or equivalent to a volume of 203 gallons of gasoline Added to the estimated 410 gallons of hydrocarbons extracted from the SVE system since 11 April ' 2000, the total vola ne of hydrocarbons extracted to date is approximately 613 gallons The mass/volume calculations for extracted hydrocarbons are included with Appendix E A plot of the cumulative volume (gallons) of hydrocarbons extracted to date is included with Appendix F 5.0. CONCLUSIONS ' The implications from the Decembei 2000 ground water monitoring event are as follows f • Ground water flow direction at the site was generally toward the east-northeast at a gradient of 0 005 ft/ft, 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 22 feet between September 2000 ' and Decembei 2000 is probably due to seasonal fluctuation • Ground water elevation data collected on 21 December 2000 does not suggest ground water ' mounding is occurring due to the air sparging activities at the site • Wells MW-1,MW-2,MW-3 and MW-4 are approximately five feet"drowned"(i e screened below ground water elevation), and may not yield samples fully representative of shallowest ' ground water conditions, well MW-13 is approximately 70 feet "drowned" The ground water elevation appeared to be withing the screen intervals of wells MW-5 through MW-12 and should be representative of shallowest ground water conditions 1 • The elevated concentrations of petroleum hydrocarbons detected in samples collected from wells MW-2, MW-3, MW-4, MW-13, 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 wells AW-1, AW-2 and MW-3, with increasing depth, the dissolved plume apparently grades from higher concentrations to lower concentrations • From September 2000 to December 2000, a moderate to substantial decrease in concentrationG of dissol-ed TPH-g and BTEX were quantified in ground water samples Advanced GcoEnviron rental,Inc 1 I