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rr, i Mr Jeff Wong Page 3 of 4 • MW5 through MW9(B) Benzene was detected in wells MW1, MW2, and MW3 at concentrations of 13,000 ppb, 14 ppb, and 3 0 ppb, respectively No benzene was detected in wells MW4 through MW913 Toluene was detected in well MW 1 at 29,000 ppb No toluene was detected in any other site wells Ethylbenzene was detected in wells MW 1 and MW2 at concentrations of 3,400 ppb and 7 5 ppb, respectively No ethylbenzene was detected in any other site wells Xylenes were detected in wells MW1 and MW2 at concentrations of 20,000 ppb and 5 5 ppb, respectively No xylenes were detected in any other site wells MTBE was detected in wells MW1, MW2, MW3, MW4, and MW5 at concentrations of 28,000 ppb, 170 ppb, 6,600 ppb, 13,000 ppb, and 1 8 ppb, respectively No MTBE was detected in wells MW6 through MW9B No other gasoline additives were detected in any site well Tables 3 and 4 summarize groundwater analytical results Attachment C contains a copy of the laboratory report and chain-of-custody documentation Figures 3 and 4 present isoconcentration maps of MTBE and benzene, respectively, in shallow groundwater beneath the site Attachment D contains plots showing the concentrations of TPHg, benzene, and MTBE over time in all site wells 4.0 SUMMARY AND CONCLUSIONS i Free product thickness in well MW1 ranged from non-measurable to 0 07 feet between April 1, 2003 and June 30, 2003 A total of approximately 1315 gallons of product/water mixture has been removed from this well since August 16, 2001 Figure 5 presents a chart showing the measured depths to water and product over time in well MW1 Groundwater levels fell an average of 0 11 feet in the shallow aquifer between March 2003 and June 2003 Groundwater flow beneath the site was generally toward the northeast in June 2003 Based upon analytical results of groundwater samples collected from site wells in June 2003, the lateral extent of dissolved gasoline constituents in the shallow aquifer beneath the site has been defined except to south and west (upgradient) of well MW2 Based upon analytical results of groundwater samples collected from well MW9B, it does not appear that dissolved gasoline constituents in the shallow aquifer has migrated vertically to deeper water-bearing zones The next monitoring and sampling event is scheduled for September 2003 Ground Zero will notify EHD at least 48 hours prior to conducting fieldwork i G 1GROUNDZEITULEBURGIReports\QMR1200312QM2003 doc