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. 07 November 2004 AGE-NC Project No 96-0232 Page 2ofII effectiveness, P&T remediation activities were suspended on 17 August 2004 3.0. ASSESSMENT OF MTBE-IMPACTED GROUND WATER Based on current data collected at the site(first, second and third quarters of 2004),the lateral extent of shallow MTBE-Impacted ground water is present In First Zone (between 10 and 35 feet) ground water at maximum concentrations of 120 gg/l In the area of well EW-7, and at concentrations less than 100 µg/1 in the area bound by wells MW-5, EW-4, EW-5 and EW-8 through EW-10 (fuel dispenser area, UST tank pit area and the east-southeast portion of the property) The approximate March, June and September 2004 extents of First Zone MTBE-Impacted ground are illustrated on Figures 3, 4 and 5, respectively The lateral extent of deeper MTBE-Impacted ground water at the site in Second Zone (between 40 and 60 feet)ground water Is present at concentrations less than 1,900 µg11 in the area bound bywells MW-8A,MW-9A and soil borings P-39 through P-42(north and southeast portions of the property) The approximate March,June and September 2004 extents of Second Zone MTBE-Impacted ground are Illustrated on Figures 6, 7 and 8, respectively Based on cross sectional view C-C' (Figure 9),which Is a west-east view located along the south end of the property,the vertical extent of MTBE-Impacted ground water appears to be limited to depths between 35 and 45 feet bsg, only low MTBE concentrations are present at the south end of the property However,based on cross sectional view E-E' (Figure 10), which Is a southwest-northeast cross sectional view that splits the site and extends to well MW-19 on Banner Avenue, the vertical extent of MTBE-Impacted ground water at the north end of the site appears to extend to depths between 15 and 55 feet bsg,with very high MTBE concentrations present at depths between 40 and 50 feet bsg From the north end of the site, the dissolved MTBE plume appears to dive toward the south-southwest, beneath the UST area at depths between 30 and 50 feet bsg 4 0. GROUND WATER REMEDIATION ALTERNATIVES As noted above, a total of 27,086,201 gallons of MTBE-Impacted ground water has been treated at the site utilizing P&T remediation methods since 09 November 2000 (Table 2), during this time, AGE has calculated a total of 13 33 pounds of MTBE was removed from MTBE-impacted ground water However, based on the declining cost effectiveness of continuing to use P&T as the remediation method of MTBE-Impacted ground water at the site, and based on AGE's model of a third MTBE • plume located to the north being drawn onto the site,AGE believes that ground water P&T activities Advanced GeoEnvironmental,Inc