Fig. 4. Indigenous aged Cd breakthrough data for (a) the E horizon, (b) the Bh horizon, and (c) the Bh/C horizon with high flux. Curves represent predictions of Cd concentrations using the convection–dispersion (CDE) model with independently determined parameters (predicted local equilibrium [LEA]), using the optimized two-site model (TSM) with k and n determined from batch experiments (predicted TSM, batch k and n), and using the optimized TSM model with k and n also fitted (predicted TSM, optimized k and n). The TSM model parameters were optimized using the ¹¹¹Cd breakthrough curve.