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' Vacuum Extraction System Vorkplan October, 1 Firestone Store, 4N, H. El Dorado, Stockton, CA Page 3 off 8$ Table 1 ' Tank 5 Sal Saapling ftdts Tow Date Location No./ gas diesel kerosene motor oil B3 T1 E3 gs Sample Depth, ft ag/kg mgfkg 009 cg/kg mg/kg mg/kg a9/kg cg/kg ' 9125191 East gall, 11' 2,288 <10 flu I'm <8.4 8.97 9.1 16.8 9/18/91 Two Borings <L 8a 1.3-1.73 <1.8 c25 < ,N5 < '005 < .N5 <.m 11/12/91 Bottom (5-38), 13 ' 1,B88 3 <1.8 118 < .4 1.1 < .4 17.8 ' V. hall t5-31L, 11' i,888 22 <1.8 <25 < .4 8.83 6.4 23 8 S. gall (5-3), 18' 1,7M 29 <1.8 <25 < .4 8.57 4.8 13.8 During the April 1991 tank removal work, a soil ample was taken from beneath the tank on the eastern wall of the tank excavation. The soil sample location was selected because of staining noted withan the soils. The reported results of the soil analysis I indicated no detectable chlorinated compounds or PCBs. Metals within the Soils were below action levels. Only hydrocarbon related compounds were reported by the laboratory to be above action limits. Based on the April 1991 Sample results, the PHS requested that Firestone determine the horizontal and vertical extent of the hydrocarbons in the soils. Two borings, located approximately five feet north and south of the tank excavation, were advanced to a depth of 40 feet on September- 10, 1991- Soil samples were retrieved at five foot intervals. The drilling and soil sample results indicated no chemical migration Within the soil profile at the tank 5 site. Based on these results, at was concluded that there appears to be no horizontal or- vertical migration of chemicals to the north or south of the tank site and that the hydrocarbons an soils appear to be contained within the near surface soils adjacent to the tank. IIn November, 1991, Ryan-Murphy, Inc. over-excavated the soils at the tank 5 site. The over-excavation work was limited in I1 B = Benzene; T - Toluene; E = Ethylbenzene; X = Total Xylenes. 2 Gasoline reported less than 1. 0 mg/kg except an one sample from boring 2, at 15 - 16 feet - gasoline reported as 4. 3 mg/kg; in this same location, xylene was reported at 0. 024 mg/kg. 3 Diesel detected at following depths an both borings 1 and 2: 15, 30, and 40 feet. I Ryarr-Murphy lucorporated "The Good Earth Company"