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KLEINFELDER { 5 MONITORING RESULTS I The depth to groundwater was measured in each monitoring well included in this event. The depth to groundwater data was converted to elevation in reference to mean sea level for the calculation of groundwater flow direction and gradient. The seven groundwater samples were submitted under chain-of-custody procedures to Sequoia Analytical Laboratories of Sacramento, California. Table 2 is a summary of the analytical results for groundwater. For a complete report of the analytical results please refer to the chain-of- custody forms and laboratory analytical reports included in Appendix C. 5.1 WATER LEVELS - On December 20, 2004, all twenty monitoring wells and three piezometers were sounded for depth to groundwater. The depth to groundwater ranged from 46.54 feet below the top of the well casing (MW-DIS-1 ls)to 57.68 feet below the top of the well casing (MW-DIS-15). Groundwater elevations for the monitoring wells ranged from—35.72 feet (MW-DIS-6)to—38.00 feet (MW-DIS-15). Groundwater flow direction at the site is estimated to be generally towards the east/northeast with a relatively flat gradient of approximately 0.0005 ft./ft. Plate 3 shows the interpreted groundwater contours. The reported groundwater flow direction has been consistent with the historical data collected at the site Please refer to Table 1 for the recorded groundwater elevations on December 20, 2004 and past monitoring events. I : 5.2 ANALYTICAL METHODS AND REPORTED RANGES A total of seven groundwater samples were collected and submitted for analysis. The following is a list of the requested analyses and the reported ranges for groundwater samples obtained from the monitoring wells sampled this quarter; r • Total Petroleum Hydrocarbons as gasoline by EPA Method 8015M/8021B [non-detect< 50 µg/l]; • Benzene by EPA Method 8015NV8021B [non-detect <0.50 µg/1]; • Toluene by EPA Method 8015M/802 IB [non-detect< 0.50 µg/1]; • Ethylbenzene by EPA Method 8015M/8021B [non-detect<0.50 µg/1]; 0 Xylene by EPA Method 8015MI8021B [non-detect <0.50 µ.g11]; • 1,2-DCA by EPA Method 8260B [non-detect<0.50 [tg/1 to 73 µ,g/1]; • EDB by EPA Method 8260B [non-detect<0.50 µg11]; • TBA by EPA Method 8260B [non-detect <5.0 µg11]; MTBE by EPA Method 8260B [non-detect<0.50 µg11]; 12280.M0NIST05R1731JZ:1v Page 8 of 11 Q 2005,Kleinfelder,Inc. February 11,2005