SITE INFORMATION AND CORRESPONDENCE

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"sesS? NM ,, Scocktoa, California •.✓��-247 2.4 Utilities The site lies within the City of Stockton and is on city water and sewer. Sewer, water, and store: lines are located along Lower Sacramento Road. Before drilling was initiated, Underground Service Alert was contacted to locate all buried utilities. i 2.5 Well Inventory An inventory of existing domestic and municipal water supply'wells near the site was. initiated on February 22, 1989, by a Delta representative at the California Department of Water Resources (DNN R). According to DWR records, 25 wells are present within a 12-mile radius of the site. 2.6 Tank Closure Results On December 20, 1988, four underground storage tanks were excavated, removed, and transported to Triangle Construction, Inc., Sacramento, California. Eight soil samples were obtained from the bottom of the excavation and sent to Eureka Laboratories, Inc., for chemical analysis of benzene, toluene, ethylbenzene, xylenes (BTEX), and total petroleum hydrocarbons (TPH), ethylene dibromide (EDB), and i organic lead. The results indicated the soils at a depth of 15 feet contained petroleum hydrocarbons. A summary of the chemical analysis is presented in Table 2. Soil sample identification and locations are shown in Figure 2. Concentrations of TPH ranged from nondetected in samples T-1, T-2, T-3, and T4; to 4,880 ppm in T-5; 4,790 ppm in T-6; 1,500 ppm in T-7; and 120 ppm in T-8. TABLE 2 Chemical Analysis of Soil Samples from Bottom of Old Tank Excavation Concentrations in milligrams per kilogramlmglkg (ppm) Sample Date Approximate Ethyl- Organic ID Collected Depth (feed Benzene benzene Toluene Xylenes TPH' Lead T-1 1220188 15 <0.001 <0.001 <0.001 <0.001 <10.0 <0.05 T-2 1220188 15 <0.001 <0.001 <0.001 <0.001 <10.0 <0.05 T-3 1220188 15 <0.001 <0.001 <0.001 <0.001 <10.0 <0.05 T-4 1220188 15 <0.001 <0.001 <0.001. <0.001 <10.0 <0.05 T-5 1220188 15 3.0 29.6 22.4 188.0 4,880.0b 0.13 T-6 12/20/88 15 2.77 33.9 32.1 187.0 4,790.06 0.46 T-7 12/20/88 15 <0.050 10.4 1.7 74.5 1,500.0b <0.05 T-8 1220188 15 <0.005 0.095 •0.130 0.470 120.0b <0.05 'Total petroleum hydrocarbons. bldentified as gasoline.