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C'mtogical reckaics Inc. Page 3 Groundwater Monitoring Report Project No. 989.2 July 29,2002 I 1.2 Laboratory Analyses ' The groundwater samples collected on June 18, 2002, were delivered to Sherwood Labs (Department of Health Services Certification No. 1400), of Hilmar, California, for the following analyses: • Benzene, toluene, ethylbenzene and xylene (BTEX by EPA method 8020) • Gasoline range petroleum hydrocarbons (TPH-Gasoline by EPA method 8015(m)) • Fuel oxygenate suite (MTBE, DIPS, ETBE, TAME, and TBA by EPA method 8260) • 1,2-Dibromoethane and 1,2-Di chloro ethane (1,2 DCA and EDB by EPA method 8260) ' The fuel oxygenates samples, 1,2 DCA and EDB, were submitted by Sherwood Labs to Entech Analytical Labs of Santa Clara, California(DHS # 2346). A Chain of Custody was completed for all samples collected and tracked to ensure sample integrity. Laboratory data sheets with detection limits are included in Appendix C. ' On July 5, 2002, the laboratory data were submitted electronically to GeoTracker as required under AB2886. The confirmation number for the electronic submittal is 8898623287. ' 2.0 FINDINGS AND DISCUSSION 2.1 hydrology of Site On June 18, 2002, the depth to groundwater was measured in all of the wells prior to purging. Depths to groundwater ranged from a high of 7.40 feet below the top of casing to a low of 8.65 feet below the top of casing. The average depth to water was 8.16 feet below the top of casing. The wells are screened at 5 feet bgs and groundwater surface continues to be below the tops of the screens in the six monitoring wells. 1 Site-specific groundwater gradient was calculated using MW-1, MW-3 and MW-6, and found to be N16°W at 0.0054 ft/ft. The calculated groundwater gradient is displayed on the ' groundwater gradient map, Figure 3. Previous groundwater gradient calculations show a consistent bearing of north-northwest. The bearings have been measured between N05°W ' and N45°W and the slope averages 0.0062 ft/ft. Groundwater bearing and slope are summarized in Table 1 of Appendix A and are plotted on a Rose Diagram, Figure 4.