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�5_ FLUOR DANIEL GTI UNDERGROUND STORAGE TANK REMOVAL On September 19, 1996,Allwaste Transportation and Remediation Inc. of San Martin, California triple rinsed the two 10,000-gallon and one 6,000-gallon single-walled steel underground storage tanks at the site. The tank rinse water was pumped from the three USTs into a vacuum truck operated by Allwaste and transported under manifest to the Seaport Environmental facility located in Redwood City, California (Attachment 3). Prior to removal of the USTs, Maness Environmental Services removed the pavement and the fuel dispenser island located directly above the USTs. Overburden from the tank excavation was stockpiled to the north of the tankpit area. On September 19, 1996, Maness Environmental Services removed the three USTs. Personnel on site to complete and/or observe the UST removal included Mr. Robert McClellon of the SJCPHS and Mr. Ron Waddle of the City of Manteca Fire Department. All three USTs were in good condition with no visual holes or pits. The three tanks were loaded onto trucks and transported from the site by Allwaste to the Switzer Steel facility in Oakland, California (Attachment 4). Field notes are included as Attachment 5. Tank Pit Sampling On September 19, 1996, Fluor Daniel GTI collected a total of five soil samples from the tank pit area (Figure 2). One sample was collected from each end of the three USTs at a depth of 15 feet below ground surface (BGS),with the exception of the north end of the central tank that was inaccessible due to the location of the soil stockpile. The samples were collected directly from the backhoe in 6-inch-long by 2-inch-diameter brass cylindrical sleeves. The sample tubes were sealed with Teflon pads, plastic caps and tape, labeled, placed on ice in an insulated cooler, and transported under chain-of-custody manifest to Western Environmental Science and Technology, Inc. (WEST) in Davis, California for analysis. The samples were analyzed for benzene,toluene, ethylbenzene, and total xylenes (BTEX), m ethyl-te rt-b utyl- ether(MTBE), total petroleum hydrocarbons as gasoline (TPH-G), following EPA method 8020/modified 8015, and total lead by EPA method 6010. If MTBE was detected by EPA method 8020, an additional analysis by EPA method 8260 was used to confirm its presence. Tank Pit Soil Analytical Results Table 1 summarizes the soil analytical results of the soil samples collected beneath the tanks on September 19, 1996. Benzene and TPH-G concentrations in the samples collected ranged from 0.33 milligrams per kilogram (mg/kg) and 84 mg/kg, respectively, in sample T3-S-15, to 0.93 mg/kg and 220 mg/kg, respectively, in sample T1-S-15. MTBE ranged from below laboratory detection limits to 2.7 mg/kg in sample T3-N-15. Analysis by EPA method 8260 in the same sample confirmed the presence of MTBE at a concentration of 0.35 mg/kg; however,the laboratory concluded that the reported value of 0.35 mg/kg was a low estimate because a high amount of MTBE saturated the GC/MS detector and that the value reported for MTBE by EPA method 8020 should be used. Total lead concentrations in the samples 0384ustft(Sthl-55) -- Underground Storage Tank Removal Summary October 16, 1996 The Southland Corporation, 1399 North Main Street,Manteca,CA 2