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A I t J W J 25 March 2003 AGE-NC Project No 98-0433 Page 4of5 - ' Analytical results from ground water samples are summarized in Table 2 The laboratory report (CalTech ID 0301-035-1 to 9),quality assurance and quality control(QA/QC)and chain-of-custody are included in Appendix B The distribution of dissolved hydrocarbons is depicted in Figure 4 ' 4.0 SUMMARY AND CONCLUSIONS Based upon the data collected during the January 2003 monitoring event, AGE concludes ' The ground water elevations at the site ranged from 33 79 feet to 34 47 feet above MSL r • The ground water elevations inferred a north-northeast trending ndge of the water table, bisecting the site , ground water flowed west and east from the ridge On the west side of ' this ridge was a northerly-trending trough,with a depression or low spot at the former USTs location, ground water gradients ranged between 0 004 ft/ft and 0 009 f/ft East of the ridge, ' ground water flowed radially inwards in an easterly to northeasterly direction, at a gradient of approximately 0 004 ft/ft (Figure 3) • The highest concentration of TPH-g was in the area of monitonng wells MW-1, located lie adjacent to the former UST area, and,easternmost well MW-6, .free phase product was /- observed in these wells 5 ' • TPH-g concentrations in ground water decreased in the samples from well MW-6, yet the TPH-diesel concentrations increased (F _ ire A" TPH-g concentrations in ground water increased drastically in,the sample collected from well MWA over the quarter ' Benzene was detected in the sample from well MW-1 at a concentration of 250 µg/1, above the DHS' Maximum Contaminant Level I 1 ' MTBE was detected in wells MW-1, MW-2 and MW-8 at concentration of 2,600 µg/l, 6 7 µg/1 and 160 µg/l,,respectively, which are significantly above the DHS' primary MCL ' + TBA was detected in sample from well MW-8 at a concentration of 190 µg/1 + Except for MTBE and TPH-g in southernmost well MW-8 and excessive concentrations of TPH-g/d in easternmost well MW-6;the lateral extent of dissolved hydrocarbons is defined ' by the current well network 6�, �� "5-�Et1 yk'j- OX 'a.ar .1 L- � N0 W A '5 0 �Ve' E� 5.0. RECOMMENDATIONS ' Based on the results of this investigation, AGE recommends • Continued quarterly monitoring at the site, the next monitoring event should be scheduled ' for April 2003 Advanced GeoEnvironmental,Inc 1 ' J