FIELD DOCUMENTS CASE 2 - Laserfiche WebLink

Home Browse Search

Emcon 1433 North Market Boulevard •Sacramento,California 95834-1943• (916)928-3300• Fax(916)928-3341 August 11, 1995 ' Project 2788-100.01 Ms. Linda Turkatte tSan Joaquin County Public Health Services P.O. Box 2009 ' Stockton, California 95201 Re: Results of Site Characterization Study for former Desert Petroleum Station#787, ' 950 West 11th Street, Tracy, California Dear Ms. Turkatte: ' On behalf of Tosco Northwest Company (Tosco), EMCON conducted a pre-purchase Site Characterization study of the former Desert Petroleum service station located at 950 West 11th Street in Tracy, California. The purpose of the study was to collect soil and groundwater quality data beneath the site in order to document environmental conditions as part of a property transfer transaction. EMCON submitted a workplan, dated June 23, ' 1995, to your office detailing the proposed work scope. The results are presented below. The site is an operating service station (former Desert Petroleum Station #787) located on tthe southeast corner of West l lth Street and West 9th Street in Tracy, California. The property is located in San Joaquin County, in section 29, T2S, RSE, Mount Diablo Base & ' Meridian. The facility consists of a station building with four pump islands covered by a single canopy. Existing underground storage tanks (USTs) at the station consist of three 12,000-gallon, double-walled fiberglass tanks located to the north of the station building ' (Figure l). The USTs were installed in June 1988, and currently store regular unleaded, plus unleaded, and super unleaded gasoline. EMCON conducted supplemental assessment work at the site on June 29, 1995. Four HydroPunch borings (HP-1 through HP-4) were advanced to depths ranging from 15 to 16 feet below ground surface (bgs) using the hydraulic rams of a cone penetrometor test (CPT) drill rig. HP-1 was advanced on the north side of the USTs, HP-2 and HP-4 were advanced north and northeast of the pump islands, and HP-3 was drilled near the northwest corner of the station building (Figure 1). ' Soil samples were collected between 0 and 5 feet bgs from the HydroPunch borings using hand auger equipment. Additional soil samples were collected from the borings at 7.5 and ' 10 feet bgs using a split-spoon sampler advanced with the drill rig hydraulic rams. Collected soil samples were field screened for volatile organic compounds using a ' photoionization detector (PID) and described using the Unified Soil Classification System. Soils encountered in the borings consisted of silty sand from 1 to 6 feet bgs, underlain by clayey silt from 6 to 16 feet bgs (the maximum depth explored). PID readings for soil ' samples collected from the borings ranged from 0 to 1.2 ppm. One soil sample collected from each boring at 10 to 11 feet bgs was analyzed for benzene, toluene, ethylbenzene,