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Geosyntec <br /> consultants <br /> 4. DATA RESULTS,EVALUATION,AND DISCUSSION <br /> The following section describes the geologic conditions encountered during the <br /> investigation, summarizes the laboratory analytical results, and provides a discussion of <br /> and conclusions based on the investigation results. A summary of the analytical results <br /> is presented in Table 1 and on Figure 2. Boring logs documenting subsurface <br /> conditions are provided in Appendix A. The laboratory analytical reports and <br /> associated data verification checklists are presented in Appendix B. <br /> 4.1 Subsurface Stratiaraphy <br /> Subsurface materials encountered in the borings generally consisted of poor- to well- <br /> graded sand, gravel, and sandy silt and clay. In general, fill material consisting of sand <br /> with some gravel or clay was encountered to depths ranging from 5 to 8.5 feet bgs. <br /> Below the fill layer in GSB-1 and GSB-2, subsurface conditions consisted of poor- to <br /> well-graded sand to depths of 14 feet bgs to 16 feet bgs, underlain by interbedded layers <br /> of sandy clay and poor to well-graded sand to 25 feet bgs. Below the fill layer <br /> in GSB-3, subsurface conditions consisted of sandy silt to well-graded sand to 18 feet <br /> bgs, underlain by clay with varying amounts of sand to 24 feet bgs, and well-graded <br /> sand to 25 feet bgs. Sandy clay was encountered below the fill layer in GSB-4 to the <br /> total depth of 8 feet bgs. <br /> 4.2 Soil Analytical Results <br /> To assess soil impacts at the Site, soil analytical data were compared to California <br /> Human Health Screening Levels (CHHSLs; Cal EPA, 2005) for reported <br /> organochlorine herbicides and organochlorine pesticides. <br /> No organochlorine pesticides or herbicides were reported in soil samples collected at <br /> the Site, except for 4,4-dichlorodiphenyldichloroethylene (4,4'-DDE) and <br /> 4,4-dichlorodiphenyldichloroethane (4,4'-DDD). 4,4'-DDE was reported in all soil <br /> samples collected at concentrations ranging from 7.3 micrograms per kilogram (µg/kg) <br /> in GSB-2 to 38 µg/kg in GSB-4. 4,4'-DDD was reported in soil samples collected from <br /> GSB-1, GSB-3, and GSB-4 at concentrations ranging from 3 µg/kg in GSB-3 to 10 <br /> µg/kg in GSB-1. Reported concentrations of 4,4'-DDE and 4,4'-DDD were well below, <br /> the CHHSLs of 6,300 pg/kg and 9,000 gg/kg,respectively (Cal EPA,2005). <br /> Phase II ESA-1351 Dupont_FINAL_12302013 6 1/2/14 <br />