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GeologkaI Tadut cs Inc. Page 3 ' Groundwater Monitoring Report Project No. 989.2 July 24,2003 1.2 Laboratory Analyses ' The groundwater samples collected on November 19, 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 8020/8015(m)) 0 Gasoline range petroleum hydrocarbons (TPH-G by EPA method 8020/8015(m)) ' • Volatile Organic Compounds by GC/MS Fuel (MTBE, RIPE, ETBE, TAME, TBA, 1,2- DCA and EDB by EPA method 8260) ' The volatile organic compound samples were submitted by Sherwood Labs to Entech Analytical Labs of Santa Clara, California(DHS # 2346). ' The detection limits for these compounds are listed in the laboratory data sheets included in Appendix C and summarized in Table 2 of Appendix A. A Chain of Custody was completed for all samples collected and tracked to ensure sample integrity. ' On June 3 2003 the laboratory data were submitted electronically to GeoTracker as required under AB2886. The confirmation number for the electronic submittal is 6704978644. ' 2.0 FINDINGS AND DISCUSSION ' 2.1 Hydrology of Site On May 19, 2003, the depth to groundwater was measured in all of the wells prior to ' purging. Depths to groundwater, in the water table wells, ranged from a high of 7.53 feet below the top of casing to a low of 8.48 feet below the top of casing. The average depth to water was 9.06 feet below the top of casing and the average groundwater elevation at the ' site is 1.56 feet below mean sea level. The wells are screened at 5 feet bgs and groundwater surface continues to be below the tops of the screens in the nine shallow monitoring wells. ' Site-specific groundwater gradient was calculated using MW-3, MW-7 and MW-9, and found to be N34°W at 0.0042 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. Bearings have been measured between N05°W and N450W at the site and the slope historically averages 0.0050 WE Historical groundwater ' bearing and slope are summarized in Table I of Appendix A and are plotted on a Rose Diagram, Figure 4.