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0 0 Beck Property,Tracy,CA November 1985 Site Investigation AB-A--377 mg/kg AB-B -- 293 mg/kg AB-C -- ND AB-D -- ND AEMC believes the discovery of oil contaminants outside is the result of spillages/discharges associated with the operation of the oil transfer pipelines. This report further addresses this subject under the following section Property Research - Reservoir Operation. Groundwater Investigation Laboratory analyses of water samples collected from the four groundwater monitoring wells (BD-1, BD-2, BD-3 and BD-4) and the grab samples from AB-B on 3 November 1988 detected no evidence of polynuclear aromatics (EPA Method 610) or aromatic volatile organics (EPA Method 602). These groundwater analytical results confirm the absence of groundwater contamination which have been documented through repeated monitoring over the past two years. Refer to Table 2 to review depth to groundwater readings and top of casing elevations. AEMC has calculated groundwater gradients and has depicted the direction of groundwater flow over the monitoring period on Figure 4. The flow lines have been very consistent over the past one year of groundwater monitoring at the Beck property. The three downgradient wells (BD-2, BD-3 and BD-4) are properly positioned to detect any contaminants which may migrate away from the reservoir. The fact that no soluble contaminants have been detected in the downgradient wells clearly suggests that the hydrocarbon constituents at the source areas are completely immobile in the soil matrices. The groundwater sample collected from the open borehole (AB-B) was in direct contact with oil contaminated soil, however no soluble organic constituents were detected in the sample (BD-Boring B-W). Further, monitoring well BD-4 is positioned directly downgradient of the oil contamination in the saturated soil zone and outside the perimeter of the reservoir. rlbec01(2) Page 16