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_ 02 March zoos AGE-NC Project No 97-0333 1 ' Page 8 of 10 a PCE was detected in forty-six (46) out of forty-seven ground water samples analyzed at ' concentrations as high as 2,600 µg/1 (MW-3), TCE was detected in ground water samples MW-2, MW-3,MW-6,MW-7 (A-E),MW-8(B-D),MW-9A, MW-10(A-E),MW-11(C-D),MW-12 (A-D) F ' and MW-13C at concentrations as high as 240µg/l(MW-10B) An iso-concentration map displaying the estimated extent of dissolved PCE in First Zone water is depicted on Figure 10 ' No other constituents of concern were detected above laboratory reporting limits in the ground water samples collected during the fourth quarter 2004 sampling event Analytical results of ground water monitoring well samples are summarized in Tables 5 and 6 The laboratory reports (CTEL Project ' Nos CT214-0412245,-0412245 and-0501004),quality assurance/qualitycontrol(QA/QC)reports, and chain of custody forms are presented in Appendix li, GeoTracker confirmation pages of the submitted laboratory electronic deliverable format (EDF) files are included in Appendix B 1 I 4.0. SUMMARY AND CONCLUSIONS ' Previous soil characteristics data obtained by a CPT investigation enabled AGE to define four high . permeability, informal hydrogeologic units (CPT Site Investigation - Fourth Quarter 2000, dated ' 07 February 2001) The informal hydrogeologxc 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), and are separated by less-permeable, fine-grained intervals The results of pump and treat ground water remediation between 15 September and 30 December 2004 are as follows 1 , • Approximately 300,491 gallons ofhydrocarbon-impacted ground water were extracted from t well EW-1,which was completed in the First Zone aquifer A total volume of approximately 2,850,703 gallons of hydrocarbon-impacted ground water has been treated at the site since start-up In January 2002 (Table 1) ' • , Dissolved MTBE was detected from grab samples collected at the influent end of the treatment system at concentrations between 2,600 µg/1 and 6,100 µg/1, laboratory analysis of grab water samples collected at the effluent end did not detect any constituents of concern during the fourth quarter 2004 (Table 2) • Between 15 September and 30 December 2004, an estimated 6 0 pounds of MTBE were t extracted from ground water(Table 1, Appendix C), a total mass of 257 pounds of MTBE have 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 't ground water MTBE concentrations versus time are included in Appendix D, although a -� - -� slight MTBE increase-was reported at-the influent during the-September 2004 monthly - Advanced CeoEnVlronmentaf,Inc