ARCHIVED REPORTS XR0000747 - Laserfiche WebLink

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UNDERGROUND STORAGE TANK REMOVAL . The UST system was removed in'1988.-Groundwater was encountered in the tank excavation during removal. Subsequently,one soil and one grab water sample were collected from the tank excavation . in August 1988: �.. . Both sazn les were anal P p •yzed for total petroleum hydrocarbons quantified as gasoline (T H-g), stoddard solvents;paint thinner, diesel,-kerosene, motor oil (TPH-ss, TPH- thinner, TPH-d,TRH-k b 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,(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 (µg/1); 10,100 µg/l, 11,300 µ.g/1'and 9,330 µg/l,, respectively. . ' EXCAVATION OF UNDERGROUND STORAGE TANK AREA w 'The former UST area was excavated on,24 August 1995 to remove impacted soil. Excavation procedures were supervised'by a representative of AGE. Soil was excavated to a depth of 12 feet below surface grade(bsg). Approximately 100 cubic yards of impacted_ soil were removed from the farmer 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 concentrations'of54 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 compoilnds -benzene,-toluene, ethylbenzene and'total xylenes(BTEX)were detected at concentrations of 1'.1 mg/kg, 12 mg/kg, 8.1 ti • : mg/kg and.40 mg/kg,respectively::The excavated soil, 'Was stockpiled adjacent to the excavation on. plastic sheeting. - . On 09 October 1996,approximately 100 cubic yards of stockpiled soil were transported to Forward Incorporated, a Class II landfill .located iri Manteca, California::Soil: was loaded into'transport vehicles by Stokley Construction of Tracy,California and hauled to Forward byBob Evans Trucking ' of Manteca, California. The disposal of the soils was summarized in the Quarterly Report prepared by AGE, dated 21 November'l996., ; SITE ASSESSMENT ACTNITIES Six soil.probe borings were advanced-at the site on 20 December 1996. Soil arid water samples were . collected at 'discrete depth intervals from the majority, of the probe borings. Figure 2 depicts the locations of the probe borings. ; 0 TPH=g was detected in three,of the soil samples analyzed at concentrations as high.as 2,800 mg/kg ' Advanced GeoEnvironmental,Inc.