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%,.W 1%0� Site Background Information: former Tracy Diner Page 2 of 4 PREVIOUS SUBSURFACE INVESTIGATIONS On 04 May 2000, five soil probe borings were advanced at the site under the observation of an EHD representative. The probe borings were advanced in the former UST excavation, the southern and northern dispenser islands, and two assumed hydrogeologic down -gradient locations. All borings were advanced to depths of 20 feet bsg. Selected soil samples and one grab ground water sample were collected and analyzed from each soil boring. • Total petroleum hydrocarbons quantified as gasoline (TPH-g) were detected in soil samples from the former dispenser areas and former UST excavation area; the approximate depth limits of hydrocarbon -impacted soil were between 15 feet and 20 feet bsg. • TPH-g was detected in all grab ground water samples at concentrations ranging from 370 micrograms per liter (µg/1) in sample B1 -H20 to 55,000 µg11 in sample B3 -H2O. Benzene was detected in all samples except B5 -H2O at concentrations ranging from 0.54 µg11 in sample B1 -H2O to 160 µg/1 in sample B3 -H2O. Toluene was detected in all five ground water samples at concentrations ranging from 11 µg/1 to 25 µg11. Ethyibenzene was detected in sample B3 -H.0 at 58 µg11 and in sample B4 -H20 at 2.5 µg/1. Xylenes were only detected in samples B2 -H2O, B3 -H2O, and B4 -H2O at concentrations of 230 µg11, 120 µg/l, and 1.9 µg/1, respectively. MTBE was not detected in any of the ground water samples analyzed. • Benzene concentrations in samples collected from borings B2, B3, and B4 exceeded the State of California, Department of Health Services action level for drinking water. On 22 July 2003, four soil probe borings (B6 through B9) were advanced in the western boundary of the property on Adams Street. The probe borings were advanced to a total depth of 17 feet bsg. Soil samples were collected continuously from the borings at 4 -foot intervals, beginning at 2 feet bsg in boring B6 and 5 feet bsg in borings B7, B8, and B9. A grab ground water sample was collected at the water table. • TPH-g was detected in all soil samples at concentrations ranging from 17 milligrams per kilogram (mg/kg) in sample B8-13 to 72 mg/kg in sample B7-13. • The BTEX compounds ethylbenzene and xylenes were detected in all samples at maximum concentrations of 0.57 mg/kg (B9-10) and 0.1 mg/kg (B6-12), respectively. Benzene and toluene were detected in sample B8-13 at concentrations of 0.02 mg/kg and 0.01 mg/kg, respectively. • Benzene was detected in soil boring water samples B8 and B9 at 8.4 µg/l and 80 µg/1, respectively; toluene was detected in samples B6 and B9 at 10 µg/1 and 16 µg/l, respectively; ethylbenzene and xylenes were detected in all soil boring water samples at maximum concentrations of 3,100 pg/1 and 1,800 µg/1(B6), respectively. Advanced GeoEnviroamenlal, Inc.