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I ' 07 May 1999 AGE-NC Project No 95-0104 ' Page 6 of 8 C=vapor concentration (kg/m3) ' Q = extraction flow rate (m3/hr) t= operational period, in hours ' Between 18 March 1999 and 16 April 1999, the extraction unit operated a total of 590 hours The analytical results of the vapor samples combined with average flow rates (approximately 49 cfin) ' and the operational period were used to calculate the approximate mass of extracted gasoline during these periods ' The mass of hydrocarbons extracted from VW-I between 18 March 1999 and 16 April 1999 was calculated to be approximately 81 gallons The mass calculations for the pilot test are attached in Appendix E I 5.0. DISCUSSION AND CONCLUSIONS ' Based upon data collected during the April 1999 ground water monitoring event AGE concludes • Ground water flow direction in the area of MW-1 through MW-6 was generally toward the northeast at a gradient of 0 003 ft/ft, or approximately 15 feet per mile (Figure 3) • Ground water elevation at the site increased an average 5 29 feet between the January 1999 and April 1999 ground water monitoring events • Ground water was approximately 27 feet above the screen Intervals at MW-2, MW-3 and MW4, ground water was between 10 and 14 feet above the screen Intervals at MW-5 and MW-6 Therefore these wells are "drowned", and yield samples more representative of ' deeper ground water than of shallow ground water • TPH-g was detected In a water sample collected from well MW-5 at a concentration of 120 ' ,ug/l • No fuel oxygenates were detected In the ground water samples at concentrations above laboratory reporting limits • Toluene and xylenes were each detected In the ground water sample from MW-4 at a concentration of 12 µg/l No other BTEX compounds were detected above laboratory reporting limits from the analyzed samples • From January 1999 to April 1999, substantial decreasing dissolved petroleum hydrocarbon ' concentrations were observed at the site(Table 2) The decreases may be related to operation of the SVE/IAS pilot test, but may also be a result of the 5 29-foot rise In ground water levels IAdvanced GmEnvi ron mcntal,Inc