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04 September 2007 <br /> AGE-NC Project No. 95-0121 <br /> Page 2 of 3 <br /> Volume of half-ellipsoid Inner Zone: <br /> Veuipse INNER ZONE = (4/3 • rr • 150 ft • 35 feet • 23 feet ) / 2 = 31,612 ft' <br /> Volume of half-ellipsoid Outer Zone: <br /> Vellipse OUTER ZONE = Vellipse TOTAL ZONE - V ellipse INNER ZONE <br /> = 1685861 ft' - 31 ,6 ! 2 ft' = 1379249 ft' <br /> Roughly estimated porosity of the site soil is 20%. <br /> Ground Water (GW) VOUTERZONE = 137,249 ft' • 20% = 27,450 ft' <br /> GW VINNERZONE = 31 ,612 ft' • 20% = 6,322 ft' <br /> Calculated concentrations for dissolved TPH-g are based upon grab and quarterly ground water <br /> sample results for ground water samples with each volumetric shape: <br /> - Outer Zone volumetric concentrations were averaged from 13 ground water sample results <br /> collected from sample points CPT4 through CPT-3, MW-3, MW4, MW-6, MW40 <br /> through MW- 11 and AW-3 and calculated as : <br /> 30, 100 pg/l / 13 samples = average 2,315 pg/l within the Outer Zone <br /> - Inner Zone volumetric concentrations were averaged from 7 ground water sample results <br /> collected from sample points CPT-2, MW-2, MW-3, AW- 1 , AW-2 and VW- 1 and <br /> calculated as: <br /> 372,000 pg/I / 13 samples = average 53, 143 pg/1 within the Inner Zone <br /> The volume of petroleum hydrocarbon-impacted ground water (PHI-GW) can be calculated by: <br /> Where: C = concentration of gasoline (TPH-g) in ground water in converted lbs/liter <br /> Volume TPH-g INNER ZONEI <br /> GW VINNnERZONE converted to liters = 777, 803 liters <br /> C converted from 2,315 pg/I to 0.0000051 lb/liter <br />