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' proves true, then the subsurface investigation will focus primarily on evaluation of the lateral <br /> extent of PHCs in groundwater <br />' 3.1.1.1 Site 2 <br /> The former tank location at this site is beneath the southern edge of a large refrigeration dome, <br />' which was built subsequent to the tank removal, making the actual tank site inaccessible <br /> Therefore, in order to investigate the lateral and vertical extent of the petroleum hydrocarbons <br />' beneath the site, an array of three soil borings will be advanced along the southern perimeter <br /> of the dome In the initial boring (B2-1, Figure 2), continuous core samples will be collected <br /> from the approximate depth of the bottom elevation of the former tank to about 10 feet below <br /> rthe water table. These soil samples will allow characterization of the subsurface lithology and <br /> depth to groundwater at the tank site, and will provide target locations for collection of soil and <br /> groundwater samples in the subsequent two borings at this site. If the core sampling indicates <br /> that the water table is sufficiently below the bottom elevation of the former tank, soil samples <br /> for PHC analysis will be obtained from the cores at 5-foot intervals starting at 2 feet below the <br /> bottom elevation of the former tank and ending 2 feet above the water table. In addition, a <br /> groundwater sample will be collected from the first transmissive zone below the water table <br /> Two additional borings (82-2 and 132-3, Figure 2) will be advanced along the southeastern and <br /> south-southwestern edges of the dome, respectively Because of the distance of these borings <br /> from the edge of the former tank, and because the resample of soils at 16 feet bgs did not <br /> detect any PHCs, no soil samples for chemical analyses are anticipated to be needed from these <br /> borings. However, if soil screening indicates that the soils may be contaminated with PHCs, <br /> ' soil samples will be collected at 5-foot intervals starting at 2 feet below the approximate depth <br /> of the bottom elevation of the former tank and ending 2 feet above the water table <br /> Groundwater samples will be collected in these borings from the first transmissive zone below <br /> ' the water table. <br /> ' 3.1.1.2 Site 3 <br /> In order to reduce the potential for contamination of groundwater due to penetration through <br /> ' contaminated soils and translocation of contamination by drill tools, an initial boring (133-1, <br /> Figure 3) will be advanced about 10 feet away from the location of the former tanks In the <br /> initial boring, continuous core samples will be collected from the approximate depth of the <br /> ' bottom elevations of the former tanks to about 10 feet below the water table. These soil <br /> samples will allow characterization of the subsurface lithology and depth to groundwater at the <br /> tank site, and will provide target locations for collection of soil and groundwater samples in <br /> the subsequent two borings at this site If the core sampling indicates that the water table is <br /> M3 5 98117%323U3TI4 WPN <br /> BOYAPAN & ROSS, INC <br /> ' EnvLronmenta] Sctentists & EngincLrs <br />