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Date: August 25,2004 t Quarter: 3'd Quarter,2004 The elevated reporting limits were the result of dilutions performed by the laboratory in order to quantitate a target analyte. DISCUSSION: Gasoline range organics (GRO), benzene, ethylbenzene, total xylenes, methyl tert-butyl ether (MtBE), tert-butyl alcohol (TBA), and 1,2-dichloroethane (1,2-DCA) were reported above method detection limits in groundwater samples collected from site wells this quarter. Analyte concentrations were generally consistent with historical data with the following exceptions: 1,2-DCA was reported as below method detection limits in MW-2 for the first time since December 2001. In MW-5, MtBE was reported above method detection limits (1.1 micrograms per liter (jig/L)) for the first time since March 2002. GRO was reported above method detection limits (78 pg/L) in MW-6 for the first time since November 1997. GRO, benzene, ethylbenzene, total xylenes, and MtBE concentrations increased in wells VW-1, VW-2, and VW-3 relative to previous quarters but remain within historic high ranges. Additionally, TBA concentrations increased in wells VW-1 and VW-2 and 1,2-DCA concentrations increased in wells VW-2 and VW-3 this quarter.In VW-4,MtBE concentrations increased relative to previous monitoring events and 1,2-DCA increased but both analytes remain within historic ranges. Z Three air sparge wells (AS-1, AS-2, and AS-3) were i� 'n_ stallejand added to the quarterly sampling program during the second quarter 2004. GRO, benzene, toluene, ethylbenzene, total xylenes (BTEX), MtBE, and 1,2-DCA were reported above method detection limits in the groundwater samples collected from the air sparge wells during this sampling event. Analyte concentrations reported from the samples collected from the sparge wells are as follows: GRO concentrations ranged from 84 µg/L (AS-3) to 1,600 tig/L (AS-2),benzene ranged from 0.70 ttg/L (AS-3) to 56 pg/L (AS-1), toluene was reported above method detection limits (5.6 pg/L) in AS-2, ethylbenzene ranged from 2.0 pg/L (AS-3) to 36 pg/L (AS-2), total xylenes ranged from 1.4 pg/L (AS-3) to 38 pg/L (AS-2), MtBE ranged from 0.80 µg/L (AS-3) to 120 pg/L (AS-1), and 1,2-DCA concentrations ranged from 7.0 pg/L (AS-3) to 19 pg/L (AS-2). Groundwater elevations in site monitoring wells decreased relative to the previous monitoring event. The groundwater flow direction across the site was toward the northeast with an average hydraulic gradient of 0.005 ftlft. This report is based on data,site conditions, and other information that are generally applicable as of the date of the report,and the conclusions and recommendations herein are therefore applicable only to that time frame. TABLES Table 1 Groundwater Elevation and Analytical Data Table 2 Fuel Oxygenates Analytical Data Table 3 Groundwater Gradient Data FIGURES Figure 1 Groundwater Elevation Contours Figure 2 Groundwater Analytical Summary APPENDICES Appendix A Sampling and Analysis Procedures Appendix B Laboratory Analytical Reports,Chain-of-Custody Documentation, and Field Data Sheets Appendix C GeoTracker Upload Confirmation K:4WpmcmV5 BP ARC0NW5481QUWff1y0 QTR 0A548 GWMR 3Q04.doc Page 2