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I � Ms Margaret Lagorio E C 0 R August 1, 2005 Page 2 u r vt x QUARTERLY STATUS AND REMEDIATION SUMMARY REPORT Second Quarter 2005 4 a Former 76 Service Station #6981 4707 Pacific Avenue, Stockton, California SITE DESCRIPTION The subject site is a paved lot located within a Target department store parking lot at the northwest corner of the intersection of Pacific Avenue and March Lane in Stockton, , California The site was formerly a Gemco department store and service station dispensing petroleum fuel prior to purchase by Target The facility began dispensing 76 branded fuel products in 1982 All aboveground and subsurface facilities related to the service station were removed in April 2000 At the time of destruction, the facility had two gasoline underground storage tanks (UST), three fuel dispenser islands, and a station kiosk A total of 12 groundwater monitoring wells, one groundwater recovery well, eight vapor extraction wells, a VES remediation system, and a remediation compound exist at the site The nearest surface water is the Calaveras River, located approximately 2,000 feet southeast of the subject site Topography in the site vicinity is flat-lying, at an elevation of approximately 13 feet above mean sea level (msl) PREVIOUS ASSESSMENT • In May and June 1988, Applied Geosystems (AGS) collected soil samples during the , replacement of the USTs and associated product lines Petroleum hydrocarbons were detected in soil samples collected from the UST pit, product lines, and test pits adjacent to the dispensers Approximately 1,600 cubic yards of hydrocarbon-impacted soils were excavated and removed from the site Due to the proximity of roads and structures, over- excavation was terminated before all hydrocarbon impacted soils could be removed A soil vapor survey was performed to assess the extent of residual hydrocarbons in the soil beneath the site (AGS, 1988) In December 1988, AGS performed a soil vapor survey Laboratory analysis detected the presence of gasoline hydrocarbons at low concentrations in one probe hole located at the southwest corner of the site The survey did not characterize hydrocarbon contamination beyond 13 feet below ground surface (bgs) (AGS, 1989) In January and February 1990, AGS advanced five soil borings onsite to a depth of 54 5 feet bgs and installed five monitoring wells, MW-1 through MW-5 The monitoring wells were constructed of 4-inch diameter polyvinyl chloride (PVC) pipe with a 5-foot screened interval between 49 and 54 feet bgs Groundwater was encountered at approximately 51 feet bgs in all borings Laboratory analysis of soil and groundwater samples detected the presence of total petroleum hydrocarbons as gasoline (TPHg) and benzene, toluene, ethyl-benzene and total xylenes (BTEX) (AGS, 1991) In March 1992, RESNA Industries (formerly AGS, RESNA) installed three additional monitoring wells (MW-6 through MW-8) and four vapor extraction wells • (VW-1 through VW-4) onsite The monitoring wells were constructed of 2-inch diameter PVC casing with a 20-foot screened interval and set at 69 feet bgs Groundwater was 6981 2Q2005 QSSR doc SECOR International Incorporated °4 s=