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M EUTANK CL09T._IRE SM A58E95MENT E2RT Shell Ail Company 3725 Tracy Boulevard,Tracy,California Delta Project Na.40-80-412 S Paas 12 pesticides, and polychlorinated biphenyls (PCBs). The resuits frorri the chemical analysis of i. i pets nleuui constituents from the three monitoring wells are presented in Table 6. Copies of the certified laboratory reports are attached in Appendix F. l cv TABLE 6 Chenical Analysis of Ground Water Samples (Concentrations in parts per billion/ppb)Ethyl-Sample Date Sampled—Romv, Jgluene benzene Xylenes -TPH" MW-1 09-26-89 <0.2 <2.0 <2.0 <2.0 <50.0 MW-2 09-26-89 <0.2 <2.0 <2.0 <2.0 <50.0 tlI MW-3 09-26-89 <0.2 <2,0 <2.0 <2.0 <50.0 i s 'Total Petroleum Hydrocarbons. I Chemical analyses of the ground water samples for BTF.X and TPH show that the concentrations were below the detection limits. The detection limits are as follows: benzene 0.0002 ppm, toluene, ethylbenzene, and xylenes 0.002 ppm, and TPH at 0.05 ppm. it 4,0 D1iCU5S10N 4F RESULTS 4.1 Geology. Examination and classification of the soil samples and auger cuttings from 12 soil borings drilled at the site indicate that the subsurface geology consists of predominantly silt,claf,:layey silt,and silty clay to a depth of 13 feet below the ground surface. Underlying the finer grained soils are silty sands which were observed to a depth of 21 feet. A,' Gmund Wafer Fl w The water table was observed to be approximately 9 to I I feet below the ground surface,depending on the location at the site. Two sets of water level measurements were collected on September 26, and October 13, 1989. The direction of ground water flow on September 26, 1989, was to the north- northeast at a gradient of 0.001 foot/foot, and on October 13, 1989, was to the north-northwest at the same gradient.