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' Fourth quarter 2004 Groundwater Monitoring Report Eckert Cold Storage,Manteca,California February 8,2005 t Page 2 • FIELD OBSERVATIONS ' On December 30, 2004, Condor representatives made field observations at four of the eight site monitoring wells (MW-4, MW-5, MW-7 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 No petroleum sheen or product phase was noted in the field inspection samples collected from the monitoring wells A strong hydrocarbon odor was noted in the inspection sample collected from monitoring well MW-8 and a moderate sewage odor was noted in the inspection sample ' collected from monitoring well MW-7 GROUNDWATER ELEVATIONS ' The eight site monitoring wells were measured for water levels during this quarterly monitoring event The average groundwater elevation on December 30, 2004 was approximately 4 32 feet higher than the previous sampling event conducted on September 7, 2004 The three-point solution for the site ' groundwater gradient on December 30, 2004, 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 0 003 ft/ft towards the north-northwest Groundwater elevation data for the December 30, 2004 monitoring ' event are presented in Table 1,below, and are also shown in Figure 3, Attachment A Table 1 —Groundwater Elevation Data (December 30, 2004) ' Monitoring Screened Interval(bgs) TOC Elevation[ Depth to Water Groundwater Well Elevation MW-1 13 -28 3809 1848 1961 ' * MW-2 15 -30 3790 18 16 1974 MW-3 15 -30 3831 1865 1966 ' MW-4 12-27 3784 1855 1929 MW-5 14-34 41 22* 21 83* 19 39* MW-6 13 -33 3765 1786 1979 ' MW-7 13 -33 3822 1854 1968 MW-8 17-37 3776 18 11 1965 ' `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 * Eckert indicated that they repaired MW-5 prior to the first quarter 2004 monitoring event,with no apparent change in elevation to the well tmeasuring point Historically, the groundwater gradient direction at the site has been variable, but generally to the northwest Recent (September and December, 2004) gradient directions have shifted to a more northerly ' bearing The contaminant plume, based on the current laboratory analytical results of the sample collected from MW-5 and MW-8 (discussed in the next section), may have shifted to the north ' LABORATORY ANALYTICAL RESULTS The groundwater samples collected on December 30, 2004 from monitoring wells MW-4, MW-5, MW-7, ' 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 laboratory analytical results of the groundwater samples collected from MW-4 and MW-7 are 1 �� CONDOR