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APPENDIX D <br /> VOLUME/MASS ASSUMPTIONS AND CALCULATIONS <br /> For Adsorbed TPH-g <br /> REMAINING HYDROCARBONS <br /> Based on the average hydrocarbon concentration of adsorbed TPH-g in soil samples reported from <br /> soil borings and well installation pilot borings during previous site assessments (Figures D- 1 and <br /> D-2), the following calculation for the remaining adsorbed petroleum hydrocarbons has been made. <br /> Assumptions <br /> Two roughly drawn volumetric shapes are used to represent the remaining adsorbed TPH-g: <br /> - Rectangle of dimensions : 160 feet (approximate distance from boring B-3 to well MW4) <br /> by 65 feet (approximate distance from well MW-2 to boring B- 1 ) by 15 feet (depth <br /> from 15 feet bsg to 30 feet bsg): <br /> The volume of the rectangular (V,,,) = L • W • D, where: <br /> L = length; W = width and D = depth <br /> Vtect = L • W • D = 160 feet • 65 feet • 15 feet = 156,000 ft' <br /> - Cylinder of dimensions : 20 feet radius (half diameter of the approximate distance between <br /> wells AW- 1 and MW- 10) and a depth of 70 feet (30 feet bsg to 100 feet bsg): <br /> The volume of the cylinder (V,Y,) = 7c • R' • H, where: <br /> R = radius and H = height <br /> VeY, = rc • R' • H= 3 . 14159 • (20 feet)' • 70 feet = 87,965 ff <br /> Calculated concentrations for adsorbed TPH-g are based upon soil sample results for soil samples <br /> with each volumetric shape: <br /> Rectangular volumetric concentrations were averaged from 17 soil sample results collected <br /> from 15 to 30 feet bsg from sample points B-3, AW- 1 , VW- 1 , EW4 , MW40, <br /> MW-11 and MW-4 which was calculated as : <br /> 6, 160. 1 mg/kg / 17 samples = average 362.4 mg/kg <br />