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lo Weldon Church Site Background Information Page 2 of 4 1 UNDERGROUND STORAGE TANK REMOVAL 1 The UST system was removed in 1988.Ground water was encountered in the tank excavation area during removal. Subsequently, one soil and one grab water sample were collected from the tank 1 excavation in August 1988. Both samples were analyzed for total petroleum hydrocarbons quantified as gasoline (TPH-g), 1 stoddard solvents, paint thinner, diesel, kerosene and motor oil (TPH-ss, TPH- thinner, TPH-d, TPH-k and TPH-mo), and volatile aromatics (benzene, toluene and total xylene). TPH-g, toluene, and xylenes were detected in the soil sample at concentrations of 560 milligrams per kilogram 1 (mg/kg),21 mg/kg,and 79 mg/kg,respectively. TPH-g, benzene, toluene, and xylenes were detected in the water sample at concentrations of 117,000 micrograms per liter (4g/1), 10,100 4g/1, 11,300 µg11, and 9,330 µg11, respectively. 1 EXCAVATION OF THE UNDERGROUND STORAGE TANK AREA The former UST area was excavated on 24 August 1995 to remove impacted soil. Excavation � P procedures were supervised by a representative from AGE. Soil was excavated to a depth of lie 12 feet bsg. Approximately 100 cubic yards of impacted soil were removed from the former UST area. ' TPH-g was detected in the soil sample collected at a depth of 8 feet bsg from the sidewall of the excavation at concentrations as high as 5,800 mg/kg and benzene was detected in the samples at a ' maximum concentration of 54 mg/kg. Petroleum hydrocarbons were not detected in soil samples collected from the floor of the excavation at a depth of 12 feet bsg. TPH-g was detected in stockpile soil samples at a concentration of 440 mg/kg and volatile aromatic compounds benzene, toluene, ' ethylbenzene, and total xylenes (BTEX) were detected at concentrations of 1.1 mg/kg, 12 mg/kg, 8.1 mg/kg,and 40 mg/kg,respectively.The excavated soil was stockpiled adjacent to the excavation on plastic sheeting_ 1 On 09 October 1996,approximately 100 cubic yards of stockpiled soil were transported to Forward Incorporated, a Class II landfill located in Manteca, California. Soil was loaded into transport ' vehicles by Stokley Construction of Tracy, California and hauled to Forward by Bob Evans Trucking of Manteca,California.The disposal of the soils was summarized in the Quarterly Report prepared by AGE, dated 21 November 1996. I SITE ASSESSMENT ACTIVITIES ' Six soil probe borings were advanced at the site on 20 December 1996. Soil and water samples were • collected at discrete depth intervals from the majority of the probe borings. Figure 2 depicts the Advanced GeoEnvironmental,Inc.