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i 04 January 2002 AGE-NC Project No 95-0173 Page 6 of 8 During the third quarter 2 00 1, the mass of hydrocarbons extracted by the SVE system was calculated to be approximately 1,062 pounds, or equivalent to a volume of 170 gallons of gasoline Added to the estimated 878 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 1,048 gallons(Table 6) 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 September 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 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 2 53 feet between June 2001 and September 2001 is probably due to seasonal fluctuation • Ground water elevation data collected on 19 September 2001 does not suggest ground water mounding is occurring due to air sparging at the site • Ground water at the site is between ten feet and 65 feet above the screen intervals (drowned) ' of wells AW-1A, AW-1B, AW-2A, 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 the screen intervals of wells MW-1 through MW-12 and should be ' representative of shallowest ground water conditions • The elevated concentrations of petroleum hydrocarbons detected in samples collected from 1 wells MW-2, 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 m the area of wells AW-1 and AW-2, with increasing depth, the dissolved plume apparently grades from higher concentrations to lower concentrations 1 • A moderate to substantial decrease in concentrations of dissolved TPH-g and BTEX were quantified in ground water samples collected from wells MW-1, MW-2, MW-3 and MW-6 (Table 2) which may be interpreted as a mass reduction of the dissolved plume due to air sparging at the site Advanced GeoEnvironmental,Inc 1