ARCHIVED REPORTS_XR0003860 - Laserfiche WebLink

Home Browse Search

30 July 2003 AGE-NC Project No 99-0584 ' Page 2 of 8 ' Based on information from Lanes of Equal Depth to Groundwater-Spring 1996, published by the San Joaquin County Flood Control and Water Conservation District,the estimated depth to ground water at the site is less then 10 feet below surface grade (bsg) Based on information from Lanes of ' Equal Elevation to Groundwater-Sprang 1996, the approximate ground water elevation at the site is less then 10 feet above mean sea level The regional ground water flows toward the northeast, although flow directions may be both locally and seasonably variable Information obtained from the UST removal indicated that ground water depth at the site is approximately 12 feet bsg 2 2 UNDERGROUND STORAGE TANK REMOVAL AGE was informed that one 10,000-gallon gasoline UST(0),one 5,000-gallon gasoline UST(#2), tone 5,000-gallon unleaded diesel UST(#1)and associated piping were removed from the site in late February 1999 According to a San Joaquin County Environmental Health Department (EHD) inspection report,petroleum hydrocarbon odor and soil discoloration were noted beneath the USTs Soil samples were collected from beneath each UST at a depth of approximately 12 feet below ' surface grade(bsg)and from beneath the ends of the former dispenser island at a depth of feet bsg, in addition, a `grab' groundwater sample was collected from the bottom north end of UST 43 The samples were sent to GeoAnalytical of Modesto for analysis 2 2 1 Hydrocarbon Impacted Soil ' TPH-g was detected at the south end of the former UST #3 at a concentration of 4 milligrams per kilogram (mg/kg) The volatile aromatic compounds benzene, ethylbenzene, toluene and total xylenes(BTEX)were detected in the soil samples collected from the south end of the former USTs #2 and 93, at concentrations up to 180 micrograms per kilogram (µg/kg) TPH-g was not detected in the soil samples collected from the dispensers, but BTEX compounds were detected at concentrations up to 62 µg/kg TPH-d was not detected in any of the UST excavation floor samples, the dispenser soil samples, or in the water sample collected from the site Methyl tertiary butyl ether(MTBE)was detected in five of the UST floor and dispenser soil samples at concentrations up to 320 gg/kg Stockpile soil from the UST removal had detectable concentrations of TPH-g, TPH-d and BTEX, as well as MTBE and tertiary-butanol(TBA) The greatest concentration of TPH-g was 120 mg/kg ' and the greatest concentration of TPH-d was 790 mg/kg BTEX compounds were detected at Advanced GeoEnviroamental,Inc