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8260 and 8015 (Modified) Quality control samples included a duplicate sample and an equipment <br /> blank <br /> FINDINGS <br /> Geology and Hydrogeology Lithology encountered in unsaturated soils during drilling of the <br /> exploratory soil borings consisted predominantly of very stiff to hard silts (ML) and clays (CL) and <br /> dense to very dense silty sands (SM), clayey sands (SC), and sands (SP) Lithology encountered in <br /> saturated soils consisted of dense to very dense SM, SC, and SP and hard CL to the total explored <br /> depth of 71 5 fbg <br /> First encountered ground water occurred in borings at depths ranging from approximately 40 to 47 <br /> flag During the ground water monitoring event, static ground water in Wells MW-1 through MW-7 <br /> was measured at depths ranging from 40 66 to 42 28 fbg <br /> Water level data collected during the ground water sampling event from Wells MW-1 through MW-7 <br /> were used to construct a ground water contour map (Plate 2) Ground water elevation data indicate a <br /> narrow hydraulic ridge oriented north-south between Wells MW-2 and MW-3 Ground water flows <br /> westerly and southeasterly away from the hydraulic ridge at an approximate hydraulic gradient of <br />. 0 01 toward the west and 0 009 toward the southeast <br /> I <br /> Soil Chemical Analytical Data Selected soil samples collected from the eight borings were <br /> submitted for chemical analyses Soil chemical analytical data are presented in Table 2 and Plate 3 <br /> and the certified analytical reports are presented in Appendix C <br /> The analytical results for soil samples collected from on-site borings SB-1 through SB-4, and MW-4 <br /> indicated that TPPH concentrations ranged from ND to 1,200 ppm and benzene concentrations <br /> ranged from ND to 6 4 ppm MTBE concentrations ranged from ND to 4 6 ppm by EPA Method <br /> 8020 Oxygenates were ND in soil samples analyzed from MW-4 <br /> The analytical results for soil samples collected from off-site borings MW-5 through MW-7 indicated <br /> that TPPH concentrations ranged from ND to 92 ppm and benzene concentrations ranged from ND <br /> to 2 9 ppm Oxygenates were ND for all samples by EPA Method 8260 <br /> Ground Water Chemical Analytical Data: Ground water chemical analytical data are presented <br /> in Table 3 Certified analytical reports are included in Blaine's report presented in Appendix B A <br /> benzene concentration map is presented on Plate 2 <br /> 374 4 <br />