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California Wglonal Water Quality C)ntrol Board Central Valley Region Peter M. Rooney rSacramento Main Office Environmental ar Internet Address: http://www.swrcb.ca.gov/-rwgcb5/home.htmi Protection 3443 Routier Road, Suite A, Sacramento, California 95827-3003 Phone (916) 255-3000 • FAX (916) 255-3015 TO: Gordon L. Boggs FROM: Mark R. List UST Program Manager Engineering Geologist DATE: 2 November 1998 SIGNATURE: SUBJECT: FILE REVIEW FOR CLOSURE CONCURRENCE, SUN WEST LIQUORS, 2449 W. KETTLEMAN LANE, ,SAN JOAQUIN COUNTY a Ed J. Schnabel Chair At the request of the San Joaquin County Environmental Health Division (SJCEHD), a file review was completed to determine if Regional Board staff agree with the SJCEHD determination of no further action required at this site. This information was obtained during my review of the Regional Board casefile, for the Sun West Liquors site. Background: On 2 July 1998, three 10,000 -gallon underground storage tanks (USTs) were removed from the site. Each UST previously contained unleaded gasoline. A total of seven tank excavation samples were collected at the time of the UST removal activities. Two of the seven samples were reported to contain elevated concentrations of petroleum hydrocarbons. The soil contamination was encountered in the northwest and southwest corners of a single tank excavation, below UST #3. Up to 4,400 mg/Kg (ppm) TPHg and 10,000 gg/kg (ppb) MTBE were reported in tank excavation soil samples collected from 14 feet and 4 feet respectively, below ground surface (bgs). Low concentrations of TPHg, BTEX, MTBE and TBA were also reported in soil samples collected below the fuel product piping. Based on elevated contaminant concentrations, SJCEHD directed the responsible party to define the Iateral and vertical extent of contamination. On 10 and 11 August 1998, five soil borings were installed at the site using push point technology. Twenty-nine soil samples were collected from the soil borings and submitted to Onsite Environmental Laboratory, and analyzed for TPHg, BTEX and the fuel oxygenates (by EPA Method 8260). Soil samples were collected from depths ranging from 8 feet to 37 feet bgs. Groundwater was not encountered in any of the soil borings. All twenty-nine soil boring samples were reported as nondetect for each analyte. On 21 August 1998, the area below the south end of the UST #3 was overexcavated and approximately 60 cubic yards of soil was removed. Four confirmation soil samples were collected after completion of overexvation activities. Two samples were collected at 21 feet bgs, one from the center and one from the east side of the UST #3 excavation, and a third sample was collected from the north wall of the excavation at 9 feet bgs. One confirmation soil sample was also collected from the north wall of the UST #2 excavation. The confirmation soil sample analytical results revealed low concentrations of TPHg, toluene, ethlybenzene, and total xylenes in the soil below the former UST #3. California Environmental Protection Agency cc, Recycled Paper