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GRANITE CONSTRUCTION — FRENCH CAMP Page 4 WKA No. 2088.09 October 10, 2005 obtained beneath the former fuel dispenser. TPH as gasoline (ranging from 1 . 0 to 54 mg/kg), diesel (ranging from 90 to 410 mg/kg) and motor oil (ranging from 82 to 130 mg/kg) were reported in the soil samples obtained from the soil stockpile. In March of 1993 soil borings 131 through B17 were drilled in the vicinity of the former USTs and dispenser islands. Soil borings Bl and B2 were constructed at approximate 30° angles from vertical beneath the former 2,000-gallon waste oil tank located adjacent to the easterly side of the shop building. The remaining borings were drilled in the vicinity of the former USTs and dispenser island. The borings ranged in depth from 16 to 26 feet bgs. The subsurface soil consists primarily of sandy silts interbedded with silty clays and fine to medium grained sands. A total of 40 soil samples were analyzed for petroleum hydrocarbons . Results of laboratory analysis of soil samples collected from the angle borings did not reveal elevated concentrations of petroleum hydrocarbons or waste oil metals. TPH as gasoline (2,000 mg/kg) and diesel (7,800 mg/kg) were detected at a depth of approximately 6.5 feet bgs beneath the former dispenser island. Subsurface soils in the vicinity of the former USTs revealed TPH as gasoline (0.63 to 930 mg/kg) at depths ranging from 16 to 26. 5 feet bgs. On March 10 and 11 , 1993 three two-inch diameter groundwater monitoring wells (MW 1 through MW3) were constructed to total depths of 39 to 40 feet bgs in the vicinity of the former USTs and dispenser islands. The wells were screened with 0,024nch slotted Schedule 40 PVC casing from 20 to 40 feet bgs. A licensed California surveyor surveyed the location and casing elevation of the wells . On March 26, 1993 water samples were obtained from the wells. The average depth to groundwater was approximately 25 feet bgs. TPH as gasoline or BTEX were not reported in groundwater samples obtained from the monitoring wells MWI or MW2. However, TPH as gasoline at a concentration of 1 , 100 micrograms per liter (µg/1) was reported in the groundwater sample obtained from monitoring well MW3 . TPH as diesel was not detected in the water samples obtained from the wells. N WALLACE , KUM. __ fr ASSOCJATE5 INC,