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WORKPLAN FOR EXCAVATION OF CONTAMINATED SOIL Kwikee Food Mart 2081 Country Club Boulevard Stockton,CA 1.0 INTRODUCTION The Kwikee Food Mart is a convenience store and gasoline station located at 2081 Country Club Boulevard in Stockton, California(Figure 1). Unleaded gasoline is stored in two 10,000-gallon underground storage tanks near the front of the store and is dispensed from a single dispenser island(Figure 2). The tanks are single-walled and must be removed prior to the 1998 deadline. The owner of the property,Mr. William Peters,does not intend to replace the tanks after their removal. Figure 2 also shows the locations of three groundwater monitoring wells on the property. These were drilled between 1990 and 1994, and have been sampled on several occasions. Trace amounts of toluene,ethylbenzene, and xylene were detected in soil samples collected at depths of 10, 15, and 20 feet in these wells,and moderate concentrations of these hydrocarbons, along with benzene and gasoline,have been detected in water samples from each well. The source of these contaminants is uncertain at this time, but might be the storage tanks or their related piping. If so,removal of the tanks could expose a larger area of contaminated soil and necessitate remediation of the site. Removal of the contaminated soil would eliminate this source of residual contamination and is an accepted means of interim site remediation. The purpose of this work plan is to describe the proposed remediation procedure. 2.0 PROCEDURES The tank removal and associated soil excavation will be performed by SEMCO, Inc. under the supervision of Upgradient Environmental Consultants. A backhoe will be used to expose th tanks, and the near-surface soil will be segregated and stockpiled separately from the soil that surrounds and underlies the tanks. After the Stockton Fire Department has certified that the tanks have been adequately prepared for removal, SEMCO will use a crane to remove the tanks. They will be cleaned and inspected for holes and petroleum staining before being placed on a flatbed truck and transported to a disposal facility. After the tanks have been removed, the backhoe will deepen the excavation approximately 2 feet and soil samples will be collected as directed by a representative of PHS/EHD. A maximum of four samples, two beneath each tank, will be collected from the backhoe bucket using a slide hammer loaded with clean brass sample sleeves. These will be capped, sealed,and placed in a cooled ice chest for subsequent laboratory analysis. While these samples are being collected, Upgradient will screen the excavation with a photo-ionization detector and examine the floor and sidewalls for petroelum stains and