SITE INFORMATION AND CORRESPONDENCE

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0 27 March 2007 AGE-NC Project No. 97-0249 Page 5 of 7 MTBE was detected by EPA Method 8260 in ground water samples MW-1,MW-2,MW-3,MW-4, MW-8 (A-C), MW-9 (A, B), and MW-10A at concentrations as high as 93 µg/1 (MW-8A). The estimated extent of dissolved MTBE in HUs 1 and 2 are depicted on Figures 9 and 10,respectively. 1,2-DCA was detected in ground water samples MW-1 through MW-6,MW-8A and MW-10(A-B) at maximum concentrations of 41 µg/1 from well MW-3; TAME was detected in ground water samples MW-1,MW-2,MW-3,MW-5,MW-6 and MW-8 (A&B)at a maximum concentration of 55 µg/1 (MW-3). The estimated extent of dissolved 1,2-DCA in HU I is depicted on Figure 11. No other fuel components were detected in the ground water samples.Previous and current analytical results of ground water monitoring well samples are summarized in Tables 3 and 4;analytical results for previous domestic water well samples are summarized in Table 5.The laboratory reports(CTEL Project Numbers: 0701106 and 0701113), quality assurance/quality control (QA/QC) reports and chain of custody forms are presented in Appendix C; GeoTracker confirmation pages of the submitted laboratory electronic deliverable format(EDF) files are included in Appendix D. 4.0. SUMMARY AND CONCLUSIONS The implications from the January 2007 ground water monitoring event are as follows: • Depth to ground water at the site varied between 9.56 feet and 14.11 feet bsg; ground water elevations ranged between 0.95 feet (MW-14D) and 1.85 feet(MW-15F) below mean sea level. • The general ground water flow direction in HU1, HU2 and HU6 was inferred to be toward the east and ground water flow direction in HU4 was inferred to be oriented toward the northeast at hydraulic gradients less than 0.001 ft/ft (Figures 3 through 6). • The most intense TPH-g-impacted ground water was reported from HU 1 in the area of wells MW-1, MW-2, MW-3, MW-6 and MW-8 (A, C) at concentrations as high as 9,400 µg/1 (Figure 7). • The most intense TPH-d-impacted ground water was reported from HU 1 in the area of wells MW-2 and MW-3 at a concentration as high as 2,100 µg/l (Figure 8). • The most intense, on-site HU 1 MTBE-impacted ground water was reported from the area of Three B's Truck Plaza wells MW-1, MW-2, MW-3, MW-8A and MW-10A at concentrations as high as 93 µg/1 from well MW-8A(Figure 9). • The most intense on-site,HU2 MTBE-impacted ground water was reported from the area of Three B's Truck Plaza well MW-813 and MW-9A at a concentration of 17 µg/1 (MW-9A; Figure 10). Advanced GeoEnAronmental,Inc.