ARCHIVED REPORTS XR0009181 - Laserfiche WebLink

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[BTEX] and methyl tertiary-butyl ether [MTBE]) or polychlorinated biphenyls I Subsequently, a geophysical (magnetometer) survey of a portion of the site was performed to locate potential anomalies(underground storage tanks [USTs] or other buried structures) • July 2002 - Exploratory trenches were excavated near the UST area utilizing a backhoe and two soil probe borings (PB-2 and PB-3) were advanced at the site, the trenches were excavated at locations identified during the magnetic survey as possible USTs or buried structures The eastern trench contained assorted waste material and excavated soil had a petroleum hydrocarbon-like odor and appeared to be stained, soil samples from the soil borings did not contain detectible concentrations of petroleum hydrocarbons at the depths I sampled Petroleum hydrocarbons and volatile organic compounds were detected in a grab ground water sample collected from soil boring PB-2 at concentrations of 270 micrograms per liter (µg/l) TPH-g, 2 6 pg/l toluene, 2 3 µg/l ethylbenzene, 27 6 µg/l total xylenes, I 3 7µg11 napthalene, 1 1 pg/l n-propylbenzene, 14µg11 1,2,4-trimethylbenzene,4 1 µg/l 1,3,5- trimethylbenzene and 1 2 µg11 n-butylbenzene, however, the detected concentrations of VOCs do not exceed the state of California Department of Health Services' Maximum ' Contaminant Levels and Action Levels • November 2002 - Two USTs (UST-1 and UST-2) were discovered during excavation of debris and hydrocarbon-impacted soil The two USTs were single-walled and appeared to ' be constructed of redwood with steel banding, the tanks were contained in separate brick vaults with concrete floors Each tank had an approximate capacity of 15,000 to 20,000 I • gallons Upon discovery of the tanks, the San Joaquin County Environmental Health Department (EHD) was notified and the tanks were removed under permit Based on analytical results of soil samples collected from beneath the tanks, it appears that the tanks ' contained diesel TPH-d was detected in each of the soil samples collected from beneath UST-1 and UST-2 and in the stockpile soil sample at concentrations ranging from 1,400 mg/kg (UST-2) to 28,000 mg/kg (UST-1) None of the other target analytes were detected ' in the samples collected I I I 1 • 1