Laserfiche WebLink
i <br /> 26 June 2002 <br /> S AGE-NC Project No 95-0143 <br /> Page 3 of 4 <br /> to 210,000 µg/1 (MW-3) BTEX compounds were detected In the same wells at maximum <br /> concentrations of 8,000µg/1 benzene,43,000 µg/1 toluene,2,200 µg/1 ethylbenzene and 29,000 µg/1 <br /> xylenes, in sample MW-3,MTBE was not detected in the samples analyzed Figure 4 illustrates the <br /> approximate extent of TPH-g and benzene contamination in ground water <br /> Analytical results of ground water samples collected during the May 2002 monitoring event are <br /> summarized on Table 2 Analytical results of historical ground water samples are summarized on <br /> Tables 3 and 4 The laboratory report (MAI Lab IDs 0205257-001A through 0205257-012A) and <br /> chain-of-custody forms are included In Appendix B <br /> 4.0 SUMMARY/CONCLUSIONS <br /> Based upon data collected from the site, AGE concludes <br /> • Ground water elevation decreased approximately 0 2 feet between February 2002 and May <br /> 2002 The inferred ground water flow direction remains variably toward the north to <br /> • northeast at the site <br /> • Ground water elevation was within the screened interval of MW-16,MW-17,MW-22,MW- <br /> 23,MW-24 and the five vapor extraction wells,but above the screened Intervals of the other <br /> seven monitoring wells, the "drowned", wells may not have yielded samples fully <br /> representative of ground water conditions near the top of the saturated zone where fuel <br /> hydrocarbons would be expected to have the greatest Impact <br /> • Petroleum hydrocarbons were detected In five of the twelve ground water monitoring wells <br /> sampled at a maximum TPH-g concentration of 210,000 pg/1 (MW-3) <br /> I Maximum BTEX concentrations of 8,000 µg/1 benzene, 43,000 µg/1 toluene, 2,200 µg/1 <br /> ethylbenzene and 29,000 µg/1 xylenes were detected In sample MW-3,these concentrations <br /> are well above California's Maximum Contaminant Levels for these products In drinking <br /> water <br /> • MTBE was not detected In samples collected from the site during the May 2002 sampling <br /> event <br />' 5.0. RECOMMENDATIONS <br /> Based upon data collected during the May 2002 and previous sampling events, AGE recommends <br /> continued quarterly monitoring of the ground water monitoring well system on the site The next <br /> • <br /> Advanced GeoEnvironmental,Inc <br /> r <br />