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Ij moderate <br /> • CONTAMINANT MASS CALCULATIONS <br /> Gonzales Trucking <br /> Mass of gasoline(TPHg) in unsaturated soil. <br /> Based on isoconcentration'contours shown in cross section. <br /> Zone 1 (>10,000 ppm TPHg)=Sphere in silt 38-42' <br /> Zone 2a(1,000-10,000 ppm TPHg)=Circular Cone in sand,silt and clay 18-30' <br /> Zone 2b(1,000-10,000 ppm TPHg)= Sphere in silt and sand 3642.5' (Subtract out Zone 1 Volume) <br /> Zone 3a (100-1,000 ppm TPHg) = Frustrum of Right Circular Cone in sand, silt and clay 13-31'(Subtract out Zone 2a) <br /> Zone 3b(100-1,000 ppm TPHg) =Sphere in silt and sand 35-43' (Subtracting out Zones 1 and 2b) <br /> Zone 4a(10-100 ppm TPHg) = Frustrum of Right Circular Cone in sand, silt and clay 13-32' (Subtract out Zones 2a and 3a) <br /> Zone 4b(10-100 ppm TPHg) = Sphere in silt and sand 33-44' (Subtracting out Zones 1, 2b and 3b) <br /> Zone 5(1-10 ppm TPHg)= Frustrum of Right Circular Cone in sand, silt and clay 13-46'(Subtract out all other zones) <br /> Mass= (Volume of impacted zone)(soil density)(Average Concentiation)(E-6); <br /> Soil density assumed 45.5 kg/cu.ft.(100lb/cu. ft.); <br /> Average concentration used is average of all analytical results within affected zone. <br /> Where concentration is ND, 1/2 detection limit used. <br /> If only one result is available within a zone,then the contour value is used in averaging. <br /> Radius of Zone Volume(cu. Average Mass of <br /> Contaminant R" Pi Concentration Contaminant <br /> of Impact(ft) ft.) (mg/kg) (kg) <br /> TPHG Zone 1 3 271 3.141592654 113 20500 105 <br /> TPHG Zone 2a 4 16 3.141592654 201 1300 12 <br /> TPHG Zone 2b 5 125 3.141592654 411 5500 103 <br /> TPHG Zone 3a r1=2 r2=5 39 3.141592654 534 550 13 <br /> TPHG Zone 3b 8 512 3.141592654 1621 550 41 <br /> TPHG Zone 4a r1=4 r2=7 93 3.141592654 1115 551 3 <br /> TPHG Zone 4b 10 1000 3.141592654 2044 551 5 <br /> TPHG Zone 5 r,=6 r2=12 252 3.141592654 2669 5.51 1 <br /> Total mass of TPHG in Unsaturated Soil= 283 <br /> Average Concentration of TPHG in Unsaturated Soil= I 713 <br /> Equations Used for calculation of Volumes: <br /> Sphere: 413 x pi x r3 <br /> Right Circular Cone: 1/3 x pi x rzx h <br /> Frustrum of Right Circular Cone: 1/3 x pi x h (r, + r,r2 + r2 } <br /> • <br /> Page 1 <br />