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APPENDIX F <br /> DISSOLVED TPH-g VOLUME ASSUMPTIONS AND CALCULATIONS <br /> PAGE 5 OF 7 <br /> Volume Of TPH-g Impacted Ground Water Post-Remediation: <br /> Assumptions: <br /> • The distribution of dissolved TPH-g concentrations on the site can be approximated by an elliptical <br /> cylinder(Figure 10);the distribution can be separated into two contoured areas(i.e. 1,000µg/1 and <br /> 50 µg/1). <br /> • The effective porosity of soil at the site is estimated to be 40%. <br /> • The average of data collected from post-remediation ground water sampling events are representative <br /> of existing site conditions. <br /> • The thickness of dissolved plume is estimated to be between the average depth to ground water at <br /> the site and the bottom of monitoring well screen intervals (i.e. 20 feet). <br /> The area of an ellipse can be calculated by the formula: ApCg,CXC=(long radius,a)(short radius,b)(n) <br /> 1) For the estimated µg/l 1,000 ellipse cylinder volume: a=5 ft,b = 5 ft, and thickness c =20 ft <br /> Utilizing data collected from MW-2 and the 1,000µg/1 contour line(Figure 10),the average post excavation <br /> TPH-g concentration for the ellipse is estimated to be 1,950 ug/l. This concentration is equivalent to <br /> 0.000001950 grams per ml. A ml is very nearly equivalent to a cubic centimeter of water, which by <br /> definition equals one gram, this concentration is nearly a unitless number. <br /> The area of the ellipse is given by: A,000 PCs,=rc(5 ft)(5 ft)=79 ft <br /> The volume of the ellipse is given by: V1000post—A1000P.,,x c=79 ftZ x 20 ft = 1,580 ft <br /> Water occupies the porosity in the soil,which is estimated at this site to be 40%of the soil volume, so the <br /> total volume of water in the saturated portion of the ellipse cylinder is approximated by: <br /> Vj000p.s,=(0.40)(1,580 ft')=632 ft' <br /> One cubic foot of water contains 7.48 gallons,which weighs 8.337 lbs/gal,so the volume of the water in the <br /> ellipse cylinder is given by: <br /> V,000p.s,= (632 ft')(7.48 gal/ft') =4,727 gallons <br /> One gallon of water weighs 8.337 lbs/gal, so the mass of the water in the ellipse cylinder is given by: <br /> M1000post=(4,727 gallons)(8.337 lb/gal)=39,409 lbs <br />