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Atlantic Richfield Ca W ny `!/ 2 ARCO 05450,1617 West Fkemont Street,Stockton,California November 20,2001 0.0064 mg/kg, and 0.044 mg/kg,respectively, at approximately 11.5 feet below ground surface(bgs). TPHg was not detected at 11.5 feet bgs (BC, 1997). On July 30, 1996, BC drilled and installed one 2-inch groundwater monitoring well (MW-1)near the southwestern dispenser island to a depth of 25 feet bgs. Laboratory analysis reported total xylenes in all three soil samples analyzed with concentrations ranging from 0.0064 mg/kg to 0.0089 mg/kg. No other hydrocarbons were detected. Uthology encountered during drilling included interbedded silty sands to approximately 16 feet bgs and saturated clayey-silty sand from approximately 16 feet to 25 feet bgs (BC, 1997). Brown and Caldwell sampled well MW-1 on July 30, 1996,November 15, 1996, and March 19, 1997. Laboratory analysis reported concentrations of methyl tert-butyl ether (MtBE)of 35 micrograms per liter(µg/L), 8 gg/L, and 19 gg/L,respectively, during those sampling events. TPHg and BTEX were not detected in any of the three sampling events. Depth to groundwater ranged from 8.89 feet to 12.37 feet bgs (BC, 1997). On August 4, 1997,the California Regional Water Quality Control Board—Central Valley Region (CRWQCB-CVR)issued the site"No Further Action Required" status (CRWQCB-CVR, 1997). Between 1997 and 1999, well MW-1 was abandoned. A well abandonment report was not provided to SECOR, however, on November 12,2001, SECOR personnel visually confirmed the abandonment of well MW-1. On November 24, 1999,Delta Environmental Consultants,Incorporated(Delta) performed oversight and soil sampling during facility product piping and dispenser upgrade activities. Ten soil samples were collected beneath the product piping lines and eight soil samples were collected beneath the product dispensers. Laboratory analysis reported concentrations of toluene,ethyl benzene, xylenes, and MtBE of 0.0436 mg/kg, 0.0124 mg/kg,0.0925 mg/kg, and 0.201 mg/kg,respectively, in soil sample PL9-5.5. Xylene concentrations of 0.0448 and 0.0109 were also reported in soil samples PLA-4.0 and DP8-4.5,respectively. Hydrocarbons or volatile organic compounds(VOCs)were not detected in any other sample(Delta, 2000). Historical soil and groundwater analytical data is included in Attachment B. PROPOSED SCOPE OF WORK In order to define the horizontal and vertical limits of hydrocarbon impacted soil and to determine if groundwater is impacted,three soil borings (SB-1 through SB-3)will be drilled at the locations shown on Figure 2. The specific scope of work is discussed below: • Site Safety Plan. As required by the Occupational Health and Safety Administration (OSHA)Standard"Hazardous Waste Operations and Emergency Response"guidelines (29 CFR 1910.120), and by EARCM4501workplaas%AR0o 5450 WP