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Date February 5,2004 <br /> Quarter: 4`s Quarter,2003 <br /> • Elevated reporting limits were due to dilutions performed by the laboratory in order to quantitate a target <br /> analyte(s) <br /> DISCUSSION: <br /> TPHg, benzene, toluene, ethylbenzene, and total xylenes (BTEX), methyl tert-butyl ether (MtBE), and 1,2- <br /> dichloroethane (1,2-DCA) were reported above method detection limits in groundwater samples collected from site <br /> monitoring wells this quarter Analyte concentrations were generally consistent with historic data with the following <br /> exceptions TPHg and BTEX concentrations increased in MW-1 to levels generally consistent with December 2002 <br /> In MW-2, low-level concentrations of benzene and total xylenes were reported for the first time since December <br /> 2002 and a low level concentration of MtBE was reported for the first time since March 2003 /In MW-3,low-level <br /> concentrations of total xylenes were detected for the first time historically and MtBE was detected for the first time <br /> since September of 2000 "1,2-DCA was reported above method detection limits in MW-4 for the first time since <br /> sampling began for this analyte in June 2002 �MtBE concentrations continue to decrease in VW-lB"TPHg and <br /> BTEX concentrations in VW-3B were reported at the highest levels historically" Other analyte concentrations were <br /> generally consistent with previous monitoring events Groundwater elevations in wells across the site generally <br /> increased relative to the previous quarter The inferred groundwater flow direction ranged from the northeast to <br /> southwest at an average hydraulic gradient of 0 009 to 0 03 feet/foot)f04,A Ot: anal..o O+7 4-0k- 5 u1 1 31 + <br /> This report is based on data, site conditions,and other information that are generally applicable as of the date of the <br /> report,and the conclusions and recommendations herein are therefore applicable only to that time frame <br /> TABLES <br /> • Table I Groundwater Elevation and Analytical Data <br /> Table 2 Fuel Oxygenates Analytical Data <br /> FIGURES <br /> Figure 1 Groundwater Elevation Contours <br /> Figure 2 Groundwater Analytical Summary <br /> APPENDICES <br /> Appendix A Field and Laboratory Procedures <br /> Appendix B Laboratory Analytical Reports,Cham-of-Custody Documentation,and Field Data Sheets <br /> Appendix C GeoTracker Upload Confirmation <br /> • <br /> K MPmMssV5 SP ARCO\02 1 96%0u neriy%4 QTR 03\2186 GWMR 4Q03 doc Page 2 <br />