0.002 g of benzene spill occurs and information concerning the equilibrium phase partitioning of benzene is desired. The soil dry bulk density is ?b=1.5 g/cm3, the soil organic carbon content is foc=1%, water content is ?w=0.20, air content is ?a=0.15 and gasoline (oil) content is ?o =0.05. The following data is determined for benzene from chemical handbooks: Density ?ben = 0.78 g/cm3; aqueous solubility CS=1,780 mg/L; Henry’s constant KH=0.2; Koc= 83 cm3/g. Based on a unit (e.g., 1cm3 ) soil volume, calculate (a) the aqueous phase concentration of benzene (i.e., Cw, mass of benzene per volume of water, in mg/L); (b) the gas phase concentration of benzene (i.e., Ca, mass of benzene per volume of air, in mg/L); (c) the adsorbed (solid) phase concentration of benzene (i.e., Cads mass per porous medium volume, in mg/L); (d) the phase summed total concentration of benzene, CT in mg/L; (e) the soil saturation concentration limit, CT,sat, for benzene in this soil; and (f) the maximum allowable soil concentration, CT,max, that would result in groundwater impact at this site. Assume CMCL is 5 µg/L (drinking water standard) for benzene.