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y advanced 12 inches,filling the sample tubes with soil. The sample tool is then retrieved. Soil <br /> samples will be prepared for the laboratory by covering each end of the tubes with a Teflon <br /> sheet and polyethylene cap. The samples will be labeled,placed in ziplock bags, and placed in <br /> an ice-filled cooler. <br /> Subsurface soil samples will be collected at an approximate depth of 40 ft bgs from all five <br /> borings installed within the former tank and pump area and analyzed for TPH-gas,benzene, <br /> toluene,ethylbenzene,xylenes (BTEX),and oxygenates (MTBE, TAME,DIPE,ETBA,and <br /> TBA). Bulk density,specific gravity and total organic carbon(TOC)will also be collected at <br /> this depth from two of the five borings installed in this area. These samples will be collected <br /> approximately 5 feet above the water table,and will further characterize the soils within the <br /> former tank and pump area. Soil samples collected for bulk density, specific gravity, and total <br /> organic carbon will provide additional data for potential flow and transport modeling. <br /> r. <br /> Subsurface soil samples will be collected at approximate depths of 80 and 120 feet bgs from <br /> two of the five borings installed within the former tank and pump area—one upgradient and <br /> one downgradient. These samples will be analyzed for bulk density,specific gravity and total <br /> organic carbon (TOC) only,and will not be analyzed for petroleum constituents,since they are <br /> located within the saturated zone. In order to assess the extent of petroleum hydrocarbons <br /> beneath the water table,it is more appropriate to collect groundwater samples. Analytical <br /> results of dissolved phase constituents from soil samples collected from the saturated zone do <br /> not provide an accurate estimate of concentrations in either soil or groundwater,because the <br /> ,,. dissolved constituents are not distinctly separated into either of the two phases (soil and <br /> water). Analysis of such samples yield biased results. <br /> The soil sample locations,depths, analyses,and rationale, are summarized below: <br /> ti <br /> Soil Sample Location Depth Analysis Rationale <br /> Former Tank and 40 ft bgs TPH-G/BTEX, Assess presence of <br /> Pump Area Oxygenates (all 5 borings) hydrocarbons in vadose <br /> zone. <br /> ►^ Total organic carbon,bulk Input parameters for fate <br /> density,specific gravity and transport model <br /> (2 borings) <br /> Former Tank and 80 ft bgs Total organic carbon,bulk Input parameters for fate <br /> Pump Area density,specific gravity and transport model <br /> 1 boring upgradient <br /> 1 boring downgradient <br /> Former Tank and 120 ft bgs Total organic carbon,bulk Input parameters for fate <br /> Pump Area density,specific gravity and transport model <br /> 1 boring upgradient <br /> 1 boring downgradient <br /> Groundwater Samples <br /> Grab groundwater samples will be collected from each boring location using a HydropunchT <br /> sampler or equivalent sampling equipment. Upon reaching the appropriate depth for <br /> SFO/CABERNET/GRWPS/EBG/DELMONTE/PLANT_33/woRKPLAN_CPT.DOC 6 <br /> r <br />