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t 15 June 2004 AGE-NC Project No 96-0254 Page 4 of 4 4.0. SUMMARY AND CONCLUSIONS Based on the data collected during this monitoring period, AGE concludes • Ground water elevation at the site for the Fourth Quarter 2003 monitoring event was between 28 99 feet and 30 05 feet above MSL, the flow direction was north-northeast at an average gradient of 0 005 ft/ft During the First Quarter 2004, the ground water elevation was between 29 33 feet and 30 37 feet above MSL, the flow direction was north-northwest at an average gradient of 0 004 ft/ft The ground water flow measurements were consistent with previously determined flow directions • Petroleum hydrocarbon compounds were detected in ground water samples MW-4 and MW-7 during the Fourth Quarter 2003 monitoring event, and in samples MW-1A, MW-1B and MW-4 during the First Quarter 2004 monitoring event The benzene and 1,2-DCA concentrations in sample MW-7 exceeded the State of California's maximum contaminant levels in ground water of 1 µg/1 and 0 5 gg/l, respectively • Historically, shallow monitoring well MW-IB, of the well cluster which included wells MW-1B, intermediate well MW-lA and deep well MW-7, had consistent detections of . TPH-g, BTEX compounds and 1,2-DCA (Table 2) However, after a mayor site over-excavation in May 2003,there was a mix-up in well identification when the wells were re-installed in June 2003 At the time of the Fourth Quarter 2003 monitoring event, the identity of wells MW-7 and MW-1B were switched 5.0. RECOMMENDATIONS Based on the results of this investigation, AGE recommends continued quarterly ground water monitoring at the site, with the next monitoring event scheduled for May 2004 6.0. LIMITATIONS Our professional services were performed using that degree of care and skill ordinarily exercised by environmental consultants practicing in this or similar localities The findings were based mainly upon analytical results provided by an independent laboratory Evaluation of the hydrogeologic conditions at the site for the purpose of this investigation are made from a limited number of available data points (i a monitoring well ground water samples), and subsurface conditions may vary away from these data points No other warranty, expressed or implied, is made as to the professional interpretations, opinions and recommendations contained in this report Advanced GeoEnvironmental Inc