ARCHIVED REPORTS XR0000806 - Laserfiche WebLink

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h o Date- May 6,2004 Quarter: 1S'Quarter,2004 Based on the review of the analytical and hardcopy data (chain-of-custody records, blanks, dilutions, holding times, � LCS/LCSD results,MS/MSD results,and surrogate recoveries),the data are acceptable as reported by the laboratory with the following limitations • The reported results for GRO in samples MW-1, MW-4, and VW-3B are due to a discrete peak at C5 (probably MtBE) I • The reported results for methyl tert-butyl ether (MtBE) in samples MW-I, MW-4, and VW-3B may be biased high as demonstrated by a high surrogate recovery due to matrix interference i • Elevated reporting limits were due to dilutions performed by the laboratory in order to quantitate a target analyte(s) i DISCUSSION: GRO and MtBE were reported above method detection limits in groundwater samples collected from site monitoring wells this quarter Analyte concentrations were generally consistent with historic data with the following exceptions in MW-1, GRO concentrations decreased, benzene, toluene, ethylbenzene, and total xylenes (BTEX) were reported 1�amass el, ow method detection lmuts and MtBE increased relative to the previous quarter Benzene, total xylenes, and Sari �r MtBE m MW-2 and total xylenes and MtBE in MW-3 were reported as below method detection lirruts this quarter u7JYv4 , V GRO and MtBE concentrations increased in VW-1B MtBE and 1,2-dicbloroethane (1,2-DCA) were reported as below method detection limits in VW-213 this quarter�In VW-3B, BTEX were reported as below method detection k0 limits and GRO and MtBE concentrations decreased relative to the previous quarter -11 Groundwater elevations in wells across the site generally decreased relative to the previous quarter The inferred groundwater flow direction was toward the northwest at an average hydraulic gradient of 0 06 feet/foot 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 I Groundwater Elevation and Analytical Data Table 2 Fuel Oxygenates Analytical Data Table 3 Groundwater Gradient Data FIGURES r Figure i Groundwater Elevation Contours Figure 2 Groundwater Analytical Summary APPENDICES Appendix A Field and Laboratory Procedures Appendix B Laboratory Analytical Reports,Chain-of-Custody Documentation,and Field Data Sheets Appendix C GeoTracker Upload Confirmation • K 1WpmussVS BP ARCO\02186\Quanertyl1 QTR 04\2186 GWMR IQ04 do Page 2