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MASSNOLUME ASSUMPTIONS AND CALCULATIONS
<br /> Assumptions
<br /> • Utilizing Figures 7, 8 and 9,the mass distribution of total petroleum hydrocarbon concentrations on the site
<br /> can be approximated by four coned elliptical sequences (contour sequences), with the inner sequence
<br /> containing the highest TPH-g concentrations and the outer sequence containing the lowest
<br /> The area of an coned ellipse can be calculated by the formula
<br /> Vu= (long dram)(short dram)(0 7854)('/7. height), where "a" is the long diameter of the coned
<br /> ellipse,"b"is the short diameter and"c"is the height
<br /> 1) For the estimated inner sequence(5000 contour line) a = 32',b = 25',and c ^ 25'
<br /> 2) For the estimated inner-middle sequence(1000 contour line) a=47,b=40',and c=31'
<br /> 3) For the estimated outer-middle sequence(100 contour line) a=60',b=50',and c=55'
<br /> 4) For the estimated outer-middle sequence(50 contour line) a= 130',b= 120',and c=65'
<br /> The average TPH-g concentration for the coned elliptical sequences were estimated based on the contouring sequence
<br /> The sequences(reported as milligrams per kilogram,ppm)were as foIIows from highest to lowest 5000, 1000, 100 and
<br /> 50,respectively These concentrations are equivalent to 0 005000 grams per ml,0 001000 grams per ml,0 000100 grams
<br /> per mI and 0 000050 grams per ml,respectively As a gas ml is very nearly equivalent to a cubic centimeter of water,
<br /> which by definition equals one gram,these concentrations are nearly unitless numbers
<br /> 1) Approximate volume of petroleum hydrocarbon impacted soil in inner sequence(V,)
<br /> V,_(32 ft)(25 ft)(0 7854)('/7.25 ft) -4 7,854 ft' = 291 yd'
<br /> Converting 291 yd'to cm'yields approximately 222,108,777 cm' Using 15 g/cm3 as the weight of soil,the total weight
<br />' of contaminated soil is approximately 333,463,165 g
<br /> Using 5,000 parts per million(mg/kg)as the"average"concentration of gasoline in the inner sequence,the volume of
<br />' gasoline is
<br /> weight of soil •average concentration 4 333,463,165 g -0 005000= 1,665,816 g of gasoline
<br />' Converting grams of gasoline to volume of gasoline(gallons)using density of gasoline to equal 0 75
<br /> 1,665,816 g of gasoline—0 75 cm'/g=2,221,088 cm3
<br />' 2,221,088 cm3 • (I gallon—3,785 cm3) = 587 gallons of gasoline
<br /> 2) Approximate volume of petroleum hydrocarbon impacted soil in inner-middle sequence(V,M)
<br /> V,,,,,_(47 ft)(40 ft)(0 7854)('/230 ft) -4 22,148 ft' = 820 yd'
<br />' The volume of the inner sequence(Vj should be subtracted from the overall volume of the inner-middle sequence(Vo,,,)
<br /> V,,,,,-=Vim-V, 4 820 yd'-291 yd' 4 529 yd'
<br /> The volume of the inner middle sequence can be calculated by the method shown above Converting 529 yd' to cm3
<br /> yields approximately 403,918,978 cm' Using 1 5 g/cm3 as the weight of soil,the total weight of contaminated soil is
<br />' approximately 605,878,467 g Using 1,000 ppm as the"average"concentration of gasoline in the inner-middle sequence
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