Fig. 4. Attenuation of Se(IV) and Se(VI) in ash leachate by site soils. Also shown for comparison are dotted lines generated from the Freundlich model fits of the multiconcentration Se isotherms in 1 mM CaSO4. For SE1 48.5 + SE1 60 soils, Freundlich sorption fit were generated by combining the data sets from the two soils.