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23 March 2004 AGE-NC Project No. 98-0497 Page 3 of 4 3.2. ANALYTICAL RESULTS FROM GROUND WATER SAMPLES The analytical results from the 17 December 2003 ground water sampling event are as follows: • TPH-g was detected in well MW-1 at a concentration of 770 micrograms per liter(µg/l). The laboratory report noted that strongly-aged gasoline or diesel compounds were significant and there was a lighter than water immiscible sheen showing product present; • TPH-d was detected in MW-1 at a concentration of 50,000 µg/1. The laboratory report indicated significant amounts of unmodified or weakly modified diesel in the sample taken from well MW-I along with a lighter than water immiscible sheen. • BTEX compounds were not detected in the five ground water samples analyzed; • Fuel additives were not detected in the five ground water samples analyzed. Laboratory results of water samples analyzed for petroleum hydrocarbons are summarized in Table 2. Copies of the laboratory reports for the quarterly monitoring event(MAI Lab IDs 0312365- 001 through 0312365-005), QA/QC reports and chain-of-custody form are in Appendix B. 4.0. SUMMARY AND CONCLUSIONS The findings of the 17 December 2003 ground water monitoring event include the following: • Measured ground water elevation was approximately 42.14 feet below MSL,and was within -' the screened interval of each monitoring well. Ground water flow direction near the former UST location was to the southeast with an average gradient of 0.001 ft/ft. Historically, flow direction at the site has been toward the east or has had no observable gradient. • Contamination by TPH-g and TPH-d was encountered in the ground water sample collected and analyzed from MW-1. The detected concentrations of TPH-d in samples collected from -- MW-1 have fluctuated significantly during the past 8 monitoring events.Prior to June 2002, the TPH-d concentrations in well MW-1 had exhibited an overall declining trend. • Analytes of concern were not detected in samples collected from wells MW-2 through MW-5. • The TPH-g- and TPH-d-impacted ground water plume appears to be limited to the former UST area immediately surrounding MW-1,. The inferred areal extent of hydrocarbon- impacted ground water is illustrated in Figure 4. '� ,advanced GeoEnvironmentai.Inc.