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I Union Ice Company, 425 North Union Street, Stockton, California ' Phase II Revised Site Assessment, Installation of Oct 28, 1993 Monitoring Wells and Quarterly Groundwater Report Page: S ' screw caps and half gallon plastic containers provided by the laboratory Care was taken to ensure that no air space existed in the vials by inverting to check for bubbles and re- sampling, if necessary The samples were analyzed or extracted within 14 days according ' to their EPA methods Water samples collected for analysis were analyzed by EPA method 602 for BTEX compounds, and EPA method GCFID (3550/8015) for diesel/oil All analyses were conducted by Geo-Monitor, Inc , in Hespena, California, a State ' certified laboratory ' 4.0 Soil Conditions The subsurface geology of the Umon Ice Company, Union Street site in Stockton, California is characterized by interbedded, inorganic, micaceous clayey silts and silty clays ' with numerous silty, micaceous sands The silty, gravely, fine to medium grained sand below the water table (Figures 3 & 4) vanes across the site from grayish-blue to bluish- gray These sediments are typical of the valley fill deposits in the region Previously reported analysis of soil samples showed toluene contamination in MW-1 from 30 to 55 feet, and Tank 43 remedial excavation residual contamination in the floor and walls (Figures 5 & 6) All soil analyses from this investigation (MW-2,3,4) were non detect for all analyzed ' contaminants (Table 1) above the water table ' 5.0 Groundwater Conditions The water table was approximately 62 to 67 feet below ground level as the borings were being drilled This quarterly sampling interval recorded water levels averaging 60 feet below ground level, which is at an elevation averaging 46 5 feet below sea level (Table 2) The groundwater elevation data was used to calculate a gradient of N50E at 0 00261 ' ft /ft (Figure 2) The analyses of the July 7, 1993 sam Iing event shows Xylene contamination of 0 9 ug/L in MW-1 and e-benzene contamination of 0 6 ug/L in MW-2 (Table 1, figures , ppendix E) MW-3 & 4 were non detect 6.0 Conclusions and Recommendations ' Soil contamination exists in the north wall (at 20 feet) and the south floor (at 25 feet) of former Tank 43 remedial excavation Soil analyses of boring MW-1, to the north of the excavation, has contamination from 30 to 55 feet Groundwater contamination exists in monitoring wells MW-1 and MW-2, to the north and south of former Tank 43 excavation, respectively The lateral estimation of contamination is shown on Figure 7 along with the current groundwater gradient direction of North 50 degrees East (July 7 1993) This