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04 January 2006 AGE-NC Project No. 97-0301 Page 4of6 3.2. LABORATORY RESULTS OF GROUND WATER SAMPLES A total of twenty-six (23) ground water samples were submitted to CTEL for analysis. ' TPH-g was detected from wells MW-1, MW-4, MW-7 ,MW-8A and MW-9A at concentrations ranging from 100 micrograms per liter (gg/1) to 75,000 µg11 (MW-7). The estimated extent of,- dissolved f..dissolved TPH-g in First Water Zone is depicted on Figure 5. TPH-d was detected in the samples collected from wells MW-1 and MW-7 at concentrations of 9,200µg11 and 29,000µg11,respectively.` For the ninth consecutive quarterly monitoring event, TPH-k,and TPH-mo were not detected from any of the twenty-three water samples analyzed. Various BTEX constituents were detected in the samples collected from wells MW-1,MW-4,MW-6,MW-7,MW-$A and MW-8B at concentrations as high as 44,000 µg11 benzene (greatest on-site benzene concentration detected MW-7), 540 µg/l toluene(MW-1), 3,700 µg11 ethylbenzene(MW-7), and 6,300 4g/1 total xylenes(MW-7). ! 1,2-DCA was detected from wells MW-1, MW-7,MW-8A and MW-9A at concentrations ranging from 2.8 pg/1 (MW-8A) to 270 µg/l (MW-7). The estimated extent of dissolved 1,2-DCA in First Water Zone is depicted on Figure 6. TAME was detected in the water samples from wells MW-1, MW-7 and MW-8A at concentrations of 29 µg11, 410 µg11 and 6.4 µg11, respectively. MTBE was L . detected from wells MW-1, MW-6 and MW-8A at concentrations of 66 µg11, 17 pg/l and 22 µg/l� respectively. 1 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. The laboratory report (CTEL Laboratory I.D. CT214-0509214) and chain of custody forms are presented in Appendix B; GeoTracker confirmation pages of the submitted laboratory electronic deliverable . format (EDF) files are included in Appendix C. 4.0. SUMMARY AND CONCLUSIONS The implications from the 3rd Quarter 2005 ground water monitoring event are as follows: • Generally, depth to ground water at the site varied between 33.52 feet and 35.38 feet bsg; ground water elevations ranged between 21.38 feet (MW-8A) and 22.61 feet (MW-11D) below MSL. t • Ground water flow direction for the area bound by First Water Zone wells MW-1 through MW-12 was inferred to be northeast from the former UST area at an approximate gradient of 0.003 ft/ft or less(Figure 4). However,the water table surface has exhibited a cumulative ' eastward flow. Due to the low gradient at the site, slight variations in ground water measurements or changes of recharge/discharge of the local ground water could greatly Advanced GevEavironmental,Inc. I ' I