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i i ' 15 September 2003{ "� Ei AGE-NC Project No 97-0333 a Page 9-of 11 { E The Informal hydrogeologic units were defined as First Zone;(15-47 feet bsg), Second Zone(58-92 ' feet bsg, Third Zone (102-120 feet bsg) and Primary Aquifer Zone (128-150 feet bsg) The results of pump and treat ground water remediation between 27 March 2003 and 19 June 2003 are as follows • Approximately 231,275 gallons ofhydrocarbon-Impacted groundwater were extracted from well EW-1,which was completed in the First Zone aquifer A total volume of approximately 1,447,610 gallons of hydrocarbon-Impacted ground water has been treated at the site since the start-up period In January 2002 (Table 5) k • Dissolved MTBE was detected from grab samples collected at the influent-end of the treatment system at concentrations between 4,600 pg/l and 12,000 gg/l, laboratory analysis ' of grab water samples collected at the effluent-end of the pump and treat system did not G, detect any constituents of concern (Table 1) r • Between 27 March 2003 and 19 June 2003, an estimated 10 89 pounds of MTBE was extracted from ground water(Table 5,Appendix B),a total mass of 208 56 pounds of MTBE has been removed since initiation of the pump and treat system on 21 January 2002 A plot of cumulative ground water pump and treat mass removal versus time and a plot of influent ground water MTBE concentrations versus time are included in Appendix C, although a moderate increase was reported in April 2003,the overall general trend of decreasing MTBE ' ' concentrations Is evident F The results from the ground water monitoring and sampling events performed in June 2003 are as ' follows • 'Generally,depth to ground water at the site vaned between 19 and 26 feet bsg, ground water elevations range between 7 03 feet(MW-8E)and 12 64 feet(MW--5)above mean sea level The ground water elevation increased approximately 58 feet between March 2003 and June 2003 ground,water monitoring events, the average increase in may bie due to seasonal 1 fluctuation I • First Zone ground water flow was Inferred to be towards a groundwater depression In the area of well MW-3 at a gradient between 0'002 ft/ft and 0 02 ft/ft,off-site in the area of wells G MW-11, MW'12 and MW-13, ground water appeared to flow' towards the ;depression j (Figure 4) ' I Second Zone ground water flow was inferred to be towards the northwest at approximate r gradients of 0 001 ft/ft or less (Figures 5) 1 i a E Advanced GeoEnvIronmental,Inc l I `! { pp it i t