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3 SAMPLING AND ANALYSIS PLAN <br /> The primary objective of the field investigation described in this sampling and analysis <br /> plan is to determine the existence of the 500-gallon diesel tank and gather the data <br /> necessary to characterize the lateral and vertical extent of soil contamination and evalu- <br /> ate groundwater quality in the vicinity of the East Miner site. <br /> 3.1 OVERVIEW OF FIELD INVESTIGATION <br /> A geophysical survey will be used to help identify the presence of i.e diesel tank. The <br /> following types of subsurface samples will be collected: soil-gas, soil, and groundwater. <br /> Figure 3-1 shows proposed sampling locations. <br /> 3.1.1 GEOPHYSICAL SURVEY <br /> A geophysical survey using ground penetrating radar (GPR) will be performed in the <br /> area indicated on Figure 3-1 to determine if the diesel tank exists. GPR is capable of <br /> delineating subsurface structures (i.e., buried tanks). The thin wire-mesh which rein- <br /> forces the six inch thick concrete at the ground surface above the tanks is not anticipat- <br /> ed to impede the penetration of the GPR. <br /> 3.1.2 SOIL-GAS SURVEY <br /> The soil-gas survey will be performed in the vicinity of the gasoline tank (f=igure 3-1). <br /> The purpose of the soil-gas survey is to cost effectively delineate the lateral extent of <br /> the contamination. Soil-gas sampling is a viable option for contamination delineation <br /> due to the volatility of various gasoline constituents. The soil-gas survey results will <br /> qualitatively improve the understanding of lateral contamination migration. This in <br /> turn may help identify the most effective soil boring locations. Soil-gas sampling in the <br /> former gasoline tank excavation may also help to identify the vertical extent of contami- <br /> nation. <br /> Figure 3-1 presents the arras where six soil-gas samples will be taken. The sample <br /> depths will occur between 7 and 20 feet below ground surface (bgs). Preliminary ana- <br /> lytical data will be available at the completion of each day's work. The soil-gas samples <br /> will be analyzed for volatile Total Petroleum Hydrocarbons (TPH) and benzene, <br /> toluene, ethyl benzene, and xylenes (BTEX). <br /> 3.13 SUBSURFACE SOIL SAMPLES <br /> Subsurface soh samples will' be collected from seven soil borings. The soil borings will <br /> be drilled to a maximum depth that contamination is evident (drilling will occur to a <br /> minimum depth of 40 feet bgs). Soil samples will be collected at five-foot intervals. <br /> sF03160AWN003.51 3-1 <br />