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15 November 2002 iAGE-NC Project No 98-0452 Page 3 of 4 I MTBE was detected by EPA Method 8260B in the ground water samples collected from MW-1, MW-2 and MW-3 at concentrations of 1 5 micrograms per liter (µg/l), 5 2 µg/1 and 71 µg/1, respectively No other fuel additives were detected above laboratory reporting limits Analytical results of ground water samples are summarized on Tables 2 and 3 The laboratory report (MAI Lab IDs 0210002-001 through 0210002-003) and chain-of-custody forms are included In ' Appendix B 4.0. SUMMARY AND CONCLUSIONS Based upon data collected from the site, AGE concludes the following ' • Average ground water elevation at the site has remained relatively stable since monitoring began in September 2000 I • The ground water gradient was calculated to be 0 003 ft/ft with a flow direction toward the southwest,which is consistent with the flow direction determined during the second quarter . 2002 Ground water flow direction during previous monitoring events has alternated Iseasonally from the northeast to the southwest Local groundwater appears to be influenced by seasonal hydrogeologic changes • TPH-g and BTEX constituents were not detected above laboratory reporting limits in any of the ground water samples collected and analyzed • MTBE was detected in monitoring wells MW-1, MW-2 and MW-3 at concentrations of 1 5 µg/l, 5 2 µg/1 and 71 µg/1, respectively The concentrations detected in samples MW-2 and MW-3 exceeed the action level and Maximum Containment Level for MTBE in drinking water E5.0. RECOMMENDATIONS Based upon data collected from the site, AGE recommends • Continued ground water monitoring for MTBE The next quarterly monitoring event should be scheduled for December 2002 • Preparation of a work plan addendum to collect additional ground water samples to define the lateral extent of MTBE-impacted ground water at the site ■ Advanced GeoEnvironmental,Inc