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n . First quarter 2005 Groundwater Monitoring Report Eckert Cold Storage,Manteca,California March 31,2005 Page 2 FIELD OBSERVATIONS On March 9, 2005, Condor representatives made field observations at four of the eight Site monitoring wells (MW-1, MW-4, MW-5 and MW-8). Field observations included sample odor, appearance (color, clarity, and presence of petroleum product sheen or phase in samples), and water quality field parameters. Petroleum sheen and a moderate hydrocarbon odor were noted in the inspection sample collected from monitoring well MW-1. GROUNDWATER ELEVATIONS The eight Site monitoring wells were measured for water levels during this quarterly monitoring event. The average groundwater elevation on March 9, 2005 was approximately 2.25 feet higher than the previous sampling event conducted on December 30, 2004. The three-point solution for the site groundwater gradient on March 9, 2005, utilizing monitoring wells MW-3, MW-4, and MW-6, is shown in Figure 3, Attachment A, and indicates that the groundwater gradient was approximately 0.0033 ft/ft toward the northwest. Groundwater elevation data for the March 9, 2005 monitoring event are presented in Table 1,below, and are also shown in Figure 3,Attachment A. Table 1 —Groundwater Elevation Data(March 9, 2005) Monitoring Screened Interval(bgs) TOC Elevation] Depth to Water Groundwater Well Elevation MW-1 13 -28 38.09 16.20 21.89 MW-2 15 -30 37.90 15.93 21.97 MW-3 15 -30 38.31 16.38 21.93 MW-4 12-27 37.84 16.34 21.50 MW-5 14-34 41.22 19.48 21.74 MW-6 13 -33 37.65 15.65 22.00 MW-7 13—33 38.22 1 16.20 1 22.02 MW-8 17-37 37.76 1596 21.80 'TOC Elevation:Elevations are measured from the top of the well casing and are referenced to NGS Benchmark HS4486,elevation 35.03 feet using NAVD 88 datum. All measurements are in feet. Historically, the groundwater gradient direction at the site has been variable, but generally to the northwest, particularly in the last two years. The current data (March 9, 2005) are generally consistent with the historic gradient data. The September 2004 gradient direction, however, was to the north. The December 2004 gradient direction was just west of north. Those two gradient directions, therefore, represented a slight shift in groundwater flow direction relative to recent historic data. The current data represents a shift back, at least temporarily, to a more northwestern groundwater flow direction. LABORATORY ANALYTICAL RESULTS The groundwater samples collected on March 9, 2005, from monitoring wells MW-1, MW-4, MW-5, and MW-8 were analyzed for benzene, toluene, ethyl benzene, and total xylenes (BTEX) by EPA Method 8260B; total petroleum hydrocarbons quantified as gasoline (TPH-G) by EPA Method 8015M; and selected gasoline oxygenates/additives including methyl tertiary butyl ether (MTBE) by EPA Method 8260B. The current analytical results are shown in Table 2, on the next page. The laboratory analytical • results of the groundwater sample collected from MW-1 indicate that contaminant concentrations are generally an order of magnitude less than for historic monitoring results. The current sampling results for MW-1 represent the first time since December 2002 that the well has been sampled. The laboratory A �.1� CONDOR