ARCHIVED REPORTS XR0010017 - Laserfiche WebLink

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Date January 31,2006 Quarter 4'h Quarter 2005 • • The reported results for benzene in samples MW-2, VW-2, VW-3, and VW-4 and MtBE in samples VW-7 and VW-12 may be biased high due to a high percent recovery reported in the associated LCS analysis • The reported results for ethanol and xylenes in sample VW-1 may be biased low due to a low average percent recovery reported in the associated MSIMSD analysis • The reported result for 1,2-DCA in sample VW-12 should be considered estimated, the samples were initially analyzed within holding time but required dilution The dilution was performed out of holding time • The elevated reporting limits were the result of dilutions performed by the laboratory in order to quantitate a target analyte DISCUSSION. GRO, benzene, toluene, ethylbenzene, total xylenes (BTEX), MtBE, 1,2-dichlorothane (1,2-DCA), and tert-amyl methyl ether (TAME) were detected above laboratory reporting limits in groundwater samples collected from site wells this quarter In MS-2A, concentrations of benzene and toluene were detected In MS-213, MW-1, MW-2, MW-3, MW-4, MW-6, MW-7, VW-5, VW-7, and VW-12 total xylenes were detected In MW-6, GRO concentrations increased to the highest, since 2003 In MW-7, toluene was detected for the first time TAME was detected for the first time historically in VW-7 and MW-5 GRO concentrations in VW-10 and VW-11 were reported at the highest concentration historically Other analyte concentrations were generally consistent with historic data The average depth to water at the site was approximately 43 feet bgs during this quarter Groundwater elevations • generally increased relative to the previous sampling event The inferred direction of groundwater flow across the site ranged from the northeast to southeast with an average hydraulic gradient of 0 004 ft/ft 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 FIGURES Figure 1 Groundwater Elevation Contours Figure 2 Groundwater Analytical Summary TABLES Table 1 Groundwater Monitoring and Analytical Data Table 2 Fuel Oxygenates Analytical Data Table 3 Groundwater Gradient Data APPENDICES Appendix A Field and Laboratory Procedures Appendix B Laboratory Analytical Reports,Cham-of-Custody Documentation,and Field Data Sheets Appendix C GeoTracker Upload Confirmation • i K 1Wi�essO BP ARM02130NQumerly\2005%QTR 0512130 GWMR 4Q05 tl c Page 2