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t5.2 Ground Water Gradient ' A ground water gradient map was produced from the data obtained from the June 19, 1998 sampling event (Figure 2). The elevations used in the calculation are summarized in Table S. The ground water flow direction was toward the northwest during this sampling event. This gradient and flow direction is consistent with previous monitoring events. ' TABLE 4 Monitoring Well Water Elevations - .lune 19, 1998 Well Well Collar Depth to Water Ground Water Number Elevation (feet) Elevation (feet) ' (feet) MW-1 57.70' 9.69' 48.01' MW-2 1 58.82' 10.29' 48.53' MW-3 58.22' 9.75' 48.47' ' MW-4 57.46' 9.50' 47.96' MW-5 57.86' 10.14' 47.72' M W-6 57.27' 9.64' 47.63' MW-7 56.15' 7.96' 48.19' MW-9 1 56.60' 8.83' 47.77' t5.3 Discussion of Analytical Results Analytical laboratory data indicate a significant decrease in detected constituent levels in monitoring well MW-1. Individual constituent levels dropped approximately 50% as compared with the previous sampling event results. These changes are believed to be ' related to changes in the ground water elevation. These data are similar to the levels found during the June, 1997 sampling event. The sample collected from monitoring well MW-6 indicated a slight decrease for benzene from just above the detection limit during the last sampling event to below the detection ' limit this sampling event. The remaining analytes also indicated slight decreases in detected levels however these changes are not deemed significant. The remaining wells, MW-5, MW-7 and MW-9, each indicated non detectable levels for all analyzed constituents. These data are consistent with data obtained from previous quarterly sampling events. Monitoring well MW-8 was not sampled because intrusion of ' roots into the well. CA95DE-029 American Geological Services, Inc. ' 13