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parameters stabilized. Nine 4+0 ml EPA vials and one plastic bottle <br /> were collected using a disposable plastic bailer and transmitted in <br /> a chilled container to WEST Laboratories in Davis, California for <br /> analysis. <br /> 3 .4 Soil and Groundwater Analysis <br /> A total of 75 soil samples were collected. Forty-one of these were <br /> analyzed by EPA methods 8015m and. 8020 for total petroleum <br /> hydrocarbons in the gasoline range (TPH-g) and for volatile <br /> aromatic hydrocarbons (BTE&X) . The water sample was analyzed for <br /> the same components by EPA methods 8015m and 602 , and also for <br /> ethylene dibromide (EDB) , halogenated solvents, and total lead by <br /> methods 8011, 601, and 7421 . Laboratory reports and chains of <br /> custody are included in Appendix B. Subsequently, Sun Tech <br /> Environmental performed second-quarter groundwater monitoring of <br /> all wells on site and collected samples from wells MW-6 through MW- <br /> 13 and EW-1 . These samples were analyzed according to EPA methods <br /> 601, 602 , organic lead, and WET-lead, and the results are included <br />' in the findings presented below. <br /> 4. 0 FINDINGS ' <br /> 4 . 1 site Geology <br />' Figures 5 and 6 are stratigraphic cross sections that attempt to <br /> integrate boring logs and sample descriptions from this and <br /> previous investigations to depict the shallow subsurface geology at <br /> 1 the site . Large variations 'n sediment types are evident, even <br /> between fairly closely spaced borings, and it is apparent that the <br /> near-surface stratigraphy is relatively complex. Most sand beds <br />' appear to have irregular, probably erosional bases and become <br /> finer-grained upward. The large differences in the depth of the <br /> contacts between sand beds and fine-grained (silt and clay) beds in <br /> adjacent borings also suggests considerable interfingering of <br />' coarse-grained and fine-grained deposits. These characteristics are <br /> typical of fluvial channel and overbank deposits. Several channel- <br /> overbank sequences appear to be present in the vadose and shallow <br /> saturated zones. <br />' In addition some channel-overbank sequences consist of oxidized, <br /> dark-brown to red sediment , whereas others consist of unoxidized <br /> gray to light-brown sediment. The oxidized sediment is interpreted <br /> to represent a prolonged period of subaerial exposure, weathering, <br /> and erosion, and the boundary between the unoxidized and oxidized <br />' sediment does appear to represent a major irregular erosion surface <br /> (Figures 5 and 6) . Two oxidized zones and two unoxidized zones are <br /> present in the upper 70 feet, recording two periods of exposure. <br /> The stratigraphic complexity is greater in the northwest-southeast <br /> direction (Figure 5) than in the northeast-southwest direction <br /> 1 3 <br />