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15 February 2002 • AGE-NC Project No. 95-0185 ' Page 3 of 4 The relative ground water elevation at the site ranged from 37.76 to 37.38 feet. The ground water flow direction determined during this monitoring event was toward the south with a hydraulic gradient of 0.0001 feet/feet. The relative ground water elevations at the site are contoured on Figure 3. ' 3.2. GROUND WATER ANALYTICAL RESULTS ' TPH-d was detected in ground water samples collccted from each monitoring well (MW-1 through MW-4) at concentrations of 3,600 micrograms per liter (µg11), 1,100 gg/l, 430 µg/1, and 840,000 pg/l, respectively. TPH-g was detected in ground water sample MW-1 and MW-4 at ' concentrations of 120 gg/1 and 640 pg/l,respectively.Ethylbenzene and total xylenes were detected in the ground water sample from well MW-4 at concentrations of 1.1µg/1 and 0.83 µg/1,respectively. ' Current and previous analytical results are summarized in Tables 2 and 3. The laboratory report (MAI Laboratory I.D.Nos.89275 to 89278),quality control and quality assurance data(QA/QC)and ' chain-of-custody form are included in Appendix B. 4.0. CONCLUSIONS Based on the data collected during this monitoring period, AGE concludes: • Ground water flow at the site was toward the south at hydraulic gradient of approximately 0.0001, which is nearly flat. The hydraulic gradient suggests that ground water has a very slow flow rate. • The concentrations of TPH-d in samples from wells have increase'since the last monitoring ' event. BTEX compounds were generally not detectable, except for very low concentrations of ethylbenzene and total xylenes in the sample from well MW-4. 5.0. RECOMMENDATIONS Based=uponthe-results of-the,first--quarter-2002 monitoring,event;-AGE recornmends:--=-s------- - = - • Continued quarterly ground water monitoring at the,site, for dissolved TPH-d. • Preparation of a Corrective Action Plan to mitigate the dissolved TPH-d in the former UST area. Advanced GeoEnvironmental,Inc.