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Mr Jeff Wong Page 3 of 4 • Benzene was detected in wells MW2, MW3, MW4 and MW9B at 69 ppb, 3 1 ppb 2 2 ppb and 0 7 ppb, respectively No benzene was detected in wells MW5 through MW8 MTBE was detected in wells MW2, MW3, MW4, MW5, and MW6 at 460 ppb, 15,000 ppb, 18,000 ppb, 68 ppb and 2,800 ppb, respectively No MTBE was detected in wells MW7, MW8, or MW9B Toluene and xylenes were detected at relatively low levels in wells MW2 and MW9B, and ethylbenzene was detected only in well MW2 Analytical results are summarized in Table 3 Laboratory reports and chain-of-custody documentation are included in Attachment B The estimated extents of benzene and MTBE in the shallow aquifer are presented on Figures 3 and 4, respectively 4.0 SUNEY ARY AND CONCLUSIONS The measured free product in well MWI ranged from 2 04 to 0 16 feet during the reporting period Approximately 24 5 gallons of product/water mixture was removed from well MW1 during the reporting period A total of approximately 84 gallons of product/water mixture has been removed from the well since August 16, 2001 A chart showing the measured depths to water and product over time in well MW1 is presented on Figure 5 Groundwater levels fell an average of 3 73 feet in the shallow aquifer between June 2002 and September 2002, although groundwater flow remained consistent at a gradient of approximately 11 feet per mile toward the northeast The destruction of the old water supply well apparently eliminated a groundwater depression previously measured in well MW4 Since the last sampling round in June 2002, the concentration of dissolved MTBE increased in wells MW2, MW3, MW5 and MW6, while levels decreased in well MW4 and remained non- detect in wells MW7, MW8, and MW9B MTBE concentrations were at their highest recorded levels in wells MW2 and MW5 Benzene concentrations decreased in well MW6, but increased in wells MW2, MW3, and MW4 TPHg decreased in wells MW2, MW3, and MW4 Time versus concentration plots of constituents of concern (TPHg, benzene, MTBE) in site wells are included in Attachment C The lateral extent of TPHg and BTEX have been defined in groundwater beneath the site except to south and west of well MW2 Benzene was detected for the first time in well MW9B, at 0 7 ppb The lateral extent of MTBE has not been defined downgradnent of well MW6 or upgradnent of well MW2 5.0 RECOMMENDATIONS/ADDITIONAL WORK A Workplan for Additional Subsurface Investigation and Feasibility Evaluation was submitted to EHD on September 20, 2002 to address further definition of the dissolved MTBE plume and to conduct feasibility evaluation of groundwater remediation and/or plume migration control EHD has not yet provided comments or approval of the workplan GIData1GROUNDZEITULBBURG\Reporls\QNllt13QM2002 doc