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i 29 September 2000 . AGE-NC Project No 95-0173 IPage 6 of 7 The mass of hydrocarbons extracted from the SVE system was calculated to be approximately 201 gallons The mass calculations for extracted hydrocarbons are included with Appendix E 4.0. CONCLUSIONS IThe implications from the May 2000 ground water monitoring event are as follows • Ground water flow direction for the area bound by wells MW-1, MW-6, MW-7, MW-8 and I MW-12 was generally toward the northwest at a gradient of 0 004 ft/ft, or approximately 21 feet per mile (Figure 3), ground water flow direction for the area bound by wells MW-2, MW-3, MW-4, MW-5, MW-9, MW-10 and MW-11 was generally toward the southeast at I a gradient of 0 002 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 I • Ground water elevation data collected on 23 May 2000 is suggestive of a mounding effect possibly due to the air sparging activities at the site r • Wells MW-1, MW-2, MW-3 and MW-4 are approximately seven to eight feet "drowned", and may not yield samples representative of shallow ground water conditions The ground I water elevation appeared to be withmg the screen intervals of wells MW-5 and MW-6 and should be representative of shallow ground water conditions • Ground water elevation at the site increased an average 1 97 feet between the October 1999 Iand May 2000 ground water monitoring events • From October 1999 to May 2000, a moderate to substantial decrease in concentrations of I dissolved TPH-g and BTEX were quantified in ground water samples collected from wells MW-1, MW-2 and MW-6 (Table 2) The TPH-g and BTEX decreases may be attributed to air spargmg activities I • TPH-g and BTEX concentrations were detected at well MW-5 for the first time However, TPH-d was detected from MW-5 on two prior occasions and MTBE on one prior occasion • Laboratory results of ground water samples suggest that there appears to be minor MTBE- impact in the areas of wells MW-3 and MW-4 (screened 30 to 50 feet bsg) ' Based on SVE remediation data collected between 03 April 2000 and 03 June 2000,AGE concludes • The volume of hydrocarbons extracted from the inlet of the SVE system was calculated to be approximately 201 gallons of petroleum hydrocarbons (Appendix E) IAdvanced Geo Environmental,Inc I