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Two 20,000 -gallon USTs containing jet fuel were removed from the AASF fueling area in May 1998. Three soil samples per UST were collected beneath the two underlying concrete hold down slabs. Soil sample S-6 contained 0.31 milligrams per kilogram (mg/kg) benzene, 0.91 mg/kg toluene, 2.76 mg/kg ethylbenzene, 17.33 mg/kg total xylene isomers, and 184 mg/kg TPH j; TPH as kerosene was not detected. The remaining five soil samples did not contain detected concentrations of petroleum and aromatic hydrocarbons. During the UST removal contamination of soil was observed in the southeast corner of the excavation. The area of impacted soil appeared to be limited, and the UST excavation was backfilled. The location of the former USTs and layout of the AASF fueling area is shown in Figure 3. A separate work plan is being prepared on behalf of the SD-COE and the CARNG by Versar to investigate residual hydrocarbons to facilitate closure. 2.2 CSMS In March 2000,.1,630 mg/kg of TPH as hydraulic oil was detected in soil at a depth of ten feet bgs in the pressure/steam wash bay of the CSMS shop area. In addition, unknown objects potentially causing uplift of pavement in the vehicle storage area east of the CSMS building (see Figure 4) have been detected by geophysical, remote sensing methods. The locations of the objects are apparently directly below the area of greatest pavement uplift at each of the two areas. The objects, or features, are non-metallic. Ten shallow borings and surface sample locations, B -15b & c, and B-16a,b,c through B-18a,b,c, were used to collect soil and soil vapor samples to assess the impact of surface runoff to an unlined ditch draining vehicle and equipment storage areas located in the northeastern portion of the CSMS area, east of the CSMS and Armory buildings. The locations of the ditch and areas of runoff are presented in Figure 4. Composited surface samples contained motor oil -weight petroleum hydrocarbon concentrations ranging from 76 mg/kg to 475 mg/kg, and concentrations of zinc ranging from 218 mg/kg to 912 mg/kg. One composited sample contained a lead concentration of 175 mg/kg. Also in March 2000, two borings, B-10 and B-11, were advanced to investigate areas of potential environmental impact east of the CSMS building. Boring B-10 was located at a former hazardous materials storage shed. A trace concentration of hydraulic oil -weight petroleum hydrocarbon was detected at a depth of ten feet bgs, no other CDCs, including VOCs in soil vapor, were detected. Boring B-11 was advanced where sand blasting activities may have resulted in a heavy metals impact to the subsurface. The CVRWQCB recommended that shallower samples be collected in these areas to complete their assessment. 2.3 OMS The following environmental issues were identified and initially investigated by Versar in March 2000. 4 3027-03/104700.4766.230/J n23' 03