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Geosyntec° consultants o 1,2-DCB,4,4-DDE,4,4-DDT,and dicamba were also detected in shallow soil samples (<6 ft bgs). ' Concentration profiles of the COCs detected during the 1994 and 1995 investigations, that are currently detected in groundwater (1,2-DCP, chloroform, and nitrate), were presented in Figure 3 of the 2007 Annual Groundwater Monitoring Report (Geosyntec, ' 2007). Results indicated an overall reduction in concentrations with respect to depth with an increase in concentrations at the deepest sample(70.5 to 71 ft bgs). The deepest ' sample was collected at the water table, which may have resulted in a saturated or partially saturated soil sample. 2.4 Localized Geology Localized geology of the two pond areas may be relevant to understanding the ' distribution of possible residual CDCs present beneath the former ponds. In the former North Pond Area, the boring log prepared during the drilling of monitoring well MW-2 ' indicates the presence of silt from 5 to 30 ft bgs, underlain by sandy silt and silty sand to 60 ft bgs, with a gravely sand layer at 60 ft bgs (Condor, 1993). In the vicinity of the former South Pond Area, the boring log from monitoring well MW-4 documented silt ' from 5 to 35 ft bgs and predominantly silt from 35 to 60 ft bgs with interbedded layers of sandy silt(Condor, 1993). The boring logs from the MW-2 and MW-4 monitoring wells demonstrate the variation from borehole to borehole across the Site, with some logs recording predominantly silt ' in the upper 50 feet and others recording predominantly fine silty or clayey sand. These descriptions are consistent with those for the Site in general, in which the shallow ' soil has been characterized in boring logs as unconsolidated silty-sand and sandy-silt with minor clay and clayey silt, and little or no coarse-grained sand and gravel. At approximately 45 to 50 ft bgs, ten to thirty feet of sands and gravelly sands are documented in logs for most boreholes (Sierra-Pacific, 2001). ' 2.5 Historical Groundwater Elevations Relative to Pond As originally presented in the 2007 Annual Groundwater Monitoring Report, Figure 3 ' shows the former pond depths and depths to groundwater measured in the vicinity of the ponds (Geosyntec, 2007). Historical groundwater elevations observed at wells near the Work Plan Stockton Pond Inv_01-07-08 5 01.07.08