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i 02 November 2001 AGE-NC Project No 95-0173 Page 6 of 8 1,836 hours (Table 5) The average analytical results (approximately 1,440�cg/l) of the SVE air flow samples (Table 3), average flow rates (approximately 94 cfm, Table 5) and the operational period (1,836 hours) were used to calculate the approximate mass of extracted gasoline during these periods Duiing the second quarter 2001, the mass of hydrocarbons extracted by the SVE system was calculated to be apps oximately 931 pounds, or equivalent to a volume of 149 gallons of gasoline ' Added to the estimated 729 gallons of hydrocarbons extracted from the SVE system since 11 April 2000, the total volume of hydrocarbons extracted to date is estimated at 878 gallons 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 IThe implications from the June 2001 ground water monitoring event are as follows • Ground water now direction at the site was generally toward the northeast at a gradient of 0 005 ft/ft or less, due to the low gradient at the site, slight variations in ground water lie 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 72 feet between March 2001 and June 2001 is piobably due to seasonal fluctuation • Ground water elevation data collected on 20 June 2001 does not suggest ground water mounding is occurring due to air sparging at the site • Ground water at the site is appioximately five feet above the screen intervals in wells MW-1, MW-2,MW-3 and MW-4 (i e screened below ground water elevation), and may not yield samples frilly representative of shallowest ground water conditions, well MW-13 is approximately 70 feet "drowned" The ground water elevation appeared to be within the screen intervals of wells MW-5 through MW-12 and should be representative of shallowest ground water conditions "rhe Qievatecl conrentratinnc nfpetrnleiim hvrlrnrarhnnc deterred in sampleg collected frim wells MW-2, MW-3, MW-4, AW-1 and AW-2 indicate that these wells are within the dissolved petioleurn hydrocarbon "core area" of the plume (Figures 4 and 5) • The highest dissolved petroleum hydrocarbons were detected in the area of wells AW-1 and AW-2, with increasing depth the dissolved plume apparently grades from higher concentrations to lower concentrations • A moderate to substantial increase in concentrations of dissolved TPH-g and BTEX were IAdvanced GeoEnvironmental,Inc