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I <br />' 15 January 2001 <br /> AGE-NC Project No 96-0232 <br />' Page 17 of 20 <br />' on 06 October 2000 <br /> • The mass of MTBE-impacted ground water extracted from EW-1 in October 2000 was <br /> calculated to be 353,489 pounds Multiplying the average MTBE concentration (58 4g11) by <br />' the pounds of MTBE-impacted ground water yielded approximately 9 29 grams of MTBE <br /> (Appendix B) <br />' • Laboratory analysis reported significant decreases of MTBE concentrations in EW-1 over <br /> the last five consecutive sampling events <br />' The results of pump and treat ground water remediation between November and December 2000 are <br /> as follows <br /> 1 • Approximately 1,005,045 gallons of MTBE-impacted ground water were selectively <br /> extracted from wells EW-2, EW-4, EW-5, EW-6, EW-7, EW-8, EW-9 and EW-10,which <br /> are completed in the First Zone aquifer <br /> • Laboratory analysis of twelve grab water samples collected at the effluent-end of the pump <br /> lie and treat system did not detect any constituents of concern <br /> • Concentrations of dissolved MTBE were detected from extraction wells on 13 December <br /> 2000 at concentrations between 130 and 890µg/l, the greatest MTBE impacted area appears <br /> 1 to be located near the middle-west and north-west fuel dispensers (EW-7) <br /> • Dissolved MTBE was detected from grab samples collected at the influent-end of the pump <br /> and treat system at concentrations between 290 and 1,200 µg/1 <br /> • Based on 17 grab samples collected from the influent-line of the pump and treat system and <br /> samples collected from extraction wells, an average MTBE concentration of 494 ,ug/l is <br />' utilized for mass-volume calculations The mass of MTBE-impacted ground water processed <br /> from operation of the pump and treat system was calculated to be 8,643,760 pounds <br />' Multiplying the average MTBE concentration(494µg/1) by the pounds of MTBE-extracted <br /> water yielded a mass of approximately 4 27 pounds of MTBE removed from extracted <br /> ground water (Appendix L) <br /> The results from theground water monitoring and sampling events performed in December 2000 are <br />' as follows <br /> • Generally, depth to ground water at the site varied between 11 and 14 feet bsg <br />' • First and Second Zone ground water flow direction at the site appeared to be oriented toward <br /> the area of MW-1 and EW-2 at an approximate gradient of 0 009 f1/ft or less(Figures 14 and <br /> 15) Outside the area of influence of MW-1 and EW-2, the Secondary Aquifer Zone ground <br />' Advanced GeoEnvironmental,Inc <br /> 1 <br />