ARCHIVED REPORTS_XR0008047 CASE 1

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Date January 19,2006 Quarter 4"' Quarter,2005 • DISCUSSION: Gasoline range organics (GRO), benzene, ethylbenzene, total xylenes, and methyl tert-butyl ether (MtBE) were detected above laboratory reporting limits in groundwater samples collected from site wells during this quarter Ethylbenzene was detected above laboratory reporting limits in MW-6 for the first time since second quarter 2004 Other analyte concentrations were generally consistent with historic site data Groundwater elevations in the site monitoring wells generally increased relative to the previous monitoring event The inferred direction of groundwater flow across the site was toward the northwest at an average hydraulic gradient range of 0 008 fdit A regional groundwater elevation contour map (Figure 1) and a regional groundwater analytical summary(Figure 2) were created with data from the former Chevron service station at 575 Grant Line Road and the former Scotty's service station at 574 Grant Line Road Groundwater elevation and analytical data from the former Chevron and former Scotty's service stations are attached as Appendix C 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 Regional Groundwater Elevation Contours Figure 2 Groundwater Analytical Summary . TABLES Table l Groundwater Monitoring and Analytical Data Table 2 Fuel Oxygenates Analytical Data Table 3 Groundwater Gradient Data Table 4 Monitoring Well Construction Data APPENDICES Appenaix A Sampling and Analysis Procedures Appendix B Laboratory Analytical Reports,Chain-of-Custody Documentation,and Field Data Sheets Appendix C Former Chevron and Former Scotty's Groundwater Monitoring Data Appendix D GcoTracker Upload Confirmation • K\WprcK V5 6P ARCO\]1194\Quare rly\20054 QTR 05\11194 GWMR 4Q05 d— Page 2