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�.... conditions that existed and the information and data available to us during the course of this assignment. Factual information regarding operations, conditions, and test data provided by the client, owner, or their representatives have been assumed to be correct and complete. 1..3 Resources Sean Garvey, a Ground Zero geologist, directed fieldwork on April 19`i' and 20� 1999. Fisch Environmental (Fisch), a State licensed drilling company (C-57-683655), performed drilling services. Argon Laboratories, Inc. (Argon), a California state-certified hazardous waste testing laboratory(ELAP 42359), completed the laboratory analyses for all samples. 2.0 BACKGROUND INFORMATION 2.1 Initial Investigation and Underground Storage Tank Removal This site formerly operated as an automated refueling facility, and had previously utilized two 4,000-gallon underground storage tanks (UST's) containing diesel fuel and one 4,000 UST containing unleaded gasoline. On October 9, 1998 Wallace Kuhl & Associates supervised the drilling and sampling of two soil borings. Laboratory analysis of soil samples collected near the UST's and the dispenser island detected elevated levels of petroleum hydrocarbons. Analytical results are summarized in Table 1. The locations of the borings are shown on Figure 2. The UST's along with product dispensers and associated piping were removed under permit from San Joaquin County PHS/EHD on January 19, 1999. Analytical results of the soil samples collected from beneath the UST's and the former dispenser island indicated contamination by petroleum hydrocarbons. Analytical results from the tank removal are summarized in Table 1. Sample locations are depicted on Figure 2. 2.2 Hydrogeological Setting The site is located in southwestern Stockton approximately 5,500 feet south of the Stockton Deepwater Channel, the nearest body of surface water. Surface elevation at the site is approximately five feet above sea level. Based on historical information provided by San Joaquin County Flood Control and Water Conservation District, groundwater beneath the site was expected to be encountered at approximately 20 feet below ground surface(bgs), and flow in a northeasterly direction. Groundwater quality in the site vicinity is poor. The subject property is located within the plume of saline groundwater encroaching from the delta area to the west. The nearest monitored production wells, located approximately 4,000 feet northeast of the site, contain chloride and total dissolved solids in excess of MCL's. wowvgchwk-ercp u\summwy.&c 2 1