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I25 November 1997 . AGE-NC Prod ect No 95-0111 Page 3 of 4 MTBE was detected by EPA method 8020/602 in samples collected from wells MW-1, MW-4 and ' MW-5 at concentrations of 530 ppb, 22 ppb and 7 6 ppb, respectively The presence of MTBE was confirmed by analysis by EPA Method 8260 at 640 ppb, 21 ppb and 7 0 ppb Analysis of the samples by EPA Method 8260 modified for oxygenated volatile organic compounds detected tertiary butanol, chlorobenzene, and 1,4-chlorobenzene at 14 ppb, 1 2 ppb and 2 5 ppb, respectively, in MW-4 In addition, 1,2,4-trimethylbenzene was detected at 2 1 ppb in MW-2 Analytical results of ground water samples are summarized in Table 2 - 8020 and 8015m Analytical Results of Ground Water Samples Analytical results of ground water samples are summarized in Table 3 - 8260 and 8260m Analytical Results of Ground Water Samples While a comparison of the EPA method 8020 and 8260 results of ground water samples for BTE&X are summarized in Table 4 - Comparison of Analytical Results of Water Samples The laboratory report (MAI Laboratory ' Nos 77636 to 77641), QA/QC Report and chain-of-custody are included in Appendix B ' 4.0. CONCLUSIONS AND RECOMMENDATIONS ' • 4 1 CONCLUSIONS Based upon data collected from the site, AGE concludes the following ' • During the June 1997 monitoring event, ground water flow direction at the site was generally toward the northeast ' • In general, over the last quarter, concentrations of TPH-g fluctuated within the concentration range normal for this site in monitoring wells MW-1, MW-4 and MW-5, located at the northern edge of the site TPH-d concentrations increased in MWA, MW-4 and MW-5,but ' are within previous high and low concentrations for each well The concentrations of BTE&X fluctuated at low or undetectable concentrations in monitoring wells MW-1, MW- , ' 2, MW-4 and MW-5 • It appears that monitoring well MW-6 is located beyond the down-gradient margin of the plume of dissolved hydrocarbons l t ' 4 2 RECOMMENDATIONS Based on present site conditions, AGE recommends the following 1 • Advanced GeoEnvironmental Inc.