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h4 KLEINFELDER { 5 MONITORING RESULTS I 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 March 21, 2005, all 20 monitoring wells and,3 piezometers were sounded for depth to groundwater. The depth to groundwater ranged from 37.29 feet below the top of the well casing (MW-DIS-1 Is) to 55.73 feet below the top of the well casing (MW-DIS-15). Groundwater elevations for the monitoring wells ranged from -36.05 feet (MW-DIS-15) to -26.69 j feet (MW-DIS-11s). It should be noted that the recorded high and low groundwater elevations were measured from wells which exhibited groundwater mounding and depression respectively. We estimate the remediation activities are the cause of both the mound and depression and a more + representative groundwater range for high and low elevations might be characterized by the groundwater elevations noted in MW-DIS-6 (-34.26) and MW-DIS-13 (-35.00). The wells MW- DIS-lls and MW-DIS-15 were allowed to equalize, and on March 25, 2005 re-measured. The subsequent groundwater elevations appeared to have stabilized to groundwater elevations more representative of the surrounding well elevations recorded (-34.54 and -34.65 feet respectively). Groundwater flow direction at the site is calculated to be towards the cast/southeast with -a { relatively flat gradient of 0.0003 ft./ft. near the western portion of the site to 0.0005 ft./ft in the eastern portion of the site. Plate 3 shows the interpreted groundwater contours. Please refer to Table 1 for the recorded groundwater elevations on March 21, 2005 and past monitoring events. I 5.2 ANALYTICAL METHODS AND REPORTED RANGES A total of twelve 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; Total Petroleum Hydrocarbons as gasoline by EPA Method 8015M/8021B [non-detect< 130,000 [tg/1]; Benzene by EPA Method 8015M/8021B [non-detect<24,000 [tg/1]; • Toluene by EPA Method 8015M/8021B [non-detect<47,000 µg/1]; 12280.M0N/ST05 R6l 3/32:1 v Page 9 of 13 ®2005,Kleinfelder,Inc. May 20,2005 I 1