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f Third Quarter 2004 Quarterly Groundwater Monitoring Report Stockton Center Site Authority—University Park Septembe;10,2004 Page 2 of 5 Table 1 Summary of August 2004 Quarterly Groundwater Monitoring Results Field Activit Number of groundwater monitor wells 3 Number of monitor wells sampled 3 Monitor wells measured for water level 3 Date(s)monitored 08/10/04 Site Hydrology Approximate average depth to Average increase(+)/decrease H in groundwater 41.40 depths to groundwater since last(March +2.5 feet 2003) sam lin Approximate flow direction South Groundwater Contamination Wells containing free product None Wells with odor noted None Number of monitor wells with both Number of monitor wells with benzene benzene and MTBE concentrations 2 and/or MTBE concentrations at or above I' below the MCLS the MCLS Nature of contamination: Range of analyte concentrations detected Benzene in the monitor wells: Ethyl Benzene(pg/L) <0.5 11 benzene Ethyl benzene(µg/L) <0.5=5.0 Xylenes Total Xylenes(p.g/L) <1.0-3.2 { MTBE MTBE(pg/L) .<0.5 `-70 1,2-DCA 1,2-DCA(µg/L) <0.5=140 TPH-G TPH-G g/L) <50-,640 - TPH-D TPH-D(}tg/L) 80-490 Additional Information Volatile organic compounds were analyzed by EPA Method 8020. Total petroleum hydrocarbons were analyzed by EPA Method 8015M. All wells were purged prior to sampling. FIELD OBSERVATIONS On August 10, 2004, a Condor representative was on site to make field observations at the three monitor wells, MW-1, MW-2; and MW-3, as part of the third quarter 2004 quarterly groundwater monitoring event. Field observations included appearance of samples (color, clarity, and presence of petroleum product sheen or phase in samples), collection of water quality field parameters, and water level measurement. No separate phase petroleum, sheen or odor was noted in the groundwater recovered from the wells. Field '. observations are included in the groundwater monitoring field forms, attached. GROUNDWATER ELEVATIONS AND GRADIENT On August 10, 2004, the depth to groundwater was measured in monitor wells MW-1,MW-2, and MW-3. Groundwater elevation data is presented in Table 2, on the following page. The average depth to groundwater in the monitor wells was 41.40 feet below the surveyed well collar measuring points (the measuring points are slightly below the ground surface). The average groundwater elevation measured in the monitoring wells decreased 2.50 feet between March 13, 2003, and August 10, 2004. The estimated groundwater gradient for the site on August 10, 2004, was 0.0023 ft/ft to the south and is shown in Figure 2, attached. 1 I il� CONDOR