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FU1SH II MROGEOLOGIC ASSESSMEM <br /> 7910 Lower Samamento Road,Stockton,Ca ff=ia <br /> --ti Delta Project No.40.88-147 <br /> Page 10 <br /> Soil boring SB-2 was advanced near pump island soi! sample T-_. The soil sample collected at a 4-foot <br /> depth in location T-1 showed a TPH concentration of 15.0 ppm. Soil samples colieck.l in soil boring <br /> SB-2 at depths of 11.5 and 41.5 feet below grade showed trace amounts of toluene and xylenes,and levels <br /> of TPH,benzene and ethylbenzene below the detection limits of 0.2,0.002,and 0.002 ppm, respectively. <br /> �. Soil boring SB-3 was advanced through the former tank excavation backfill. During the tank excavation <br /> and removal, samples collected at a depth of apprcgdmately 15 feet in the vicinity of soil boring SP-3 <br /> shower! TPH concentrations rdnging from 120 to 4,880 ppm. Chemical analysis of the soil sample <br /> t collected in boring SB-3 at a depth of 16.5 feet below grade showed a TPH concentration of 0.2 ppm and <br /> trace amounts of BTEX constituents. A soil sample collected at 26.5 feet below ground surface in this <br /> boring also showed trace amounts of TPH and BTEX constituents. Soil samples collected at depths below <br /> 26.5 feet showed levels of petroleum constituents below the detection limits indicated in Table 2. Total <br /> lead concentrations detected in soil samples from this soil boring ranged from below the detection limit <br /> of 1.0 milli r kilogram m to 4.0 <br /> �Pe I� � fig) mg/kg. <br /> 4:9mttent al•]D(ssaiveci Constituents In Ground'Water <br /> ..'Chemical analysis of ground water samples collected on August 15,1989(Table 5),indicate that benzene <br /> present at concentrations above the detection limit and below the DHS drinking water.standards." <br /> 1 <br /> 5.0 CoNaUSiONS TCOMMENDATIONS <br /> 1 During the.tank closure process chemical analysis of soil samples T-5,T-6,T-7,and T-8 collected beneath <br /> t the former tank excavation revealed TPH concentrations of 4,880,4,790,1,500,and 120 ppm, respectively. <br /> Chemical analysis of soil sample T-3, collected beneath one of the pump islands, revealed TPH <br /> concentrations of 1,510 ppm. In order to evaluate the extent of petroleum hydrocarbons detected,Delta <br /> drilled sail boring&&SB-1,SB-2,and SB-3 near these locations. Chemical analysis of soil samples collected <br /> ( <br /> from soil borings SB-1 and SB-2 at depths of 11.5 and 41.5 feet below grade indicated TPH concentrations <br /> _ below the detection limit of 0.2 ppm. Chemical analysis of soil samples collected from soil boring SB-3 <br /> at depths of 16.5 and 26.5 feet below grade yielded TPH concentrations of 0.2 and 0.3 ppm,respectively. <br /> Laboratory analysis of soil samples collected from this soil boring at depths of 36.5, 465,and 56.0 feet <br /> below grade indicated TPH concentrations below the detection limit of 0.2 ppm. <br /> , <br /> s <br /> .. <br /> t _ <br />