A test of the local equilibrium assumption for adsorption and transport of picloram

Three sets of transport experiments were conducted to study the movement of Br^- and picloram through an Amsterdam silt loam soil in disturbed soil columns. Results indicated that Br^- breakthrough curves (BTCs) were symmetrical at each pore water velocity. In contrast, picloram BTCs were shifted to the left on a pore-volume basis and demonstrated increased tailing with increasing pore water velocities. These observations were consistent with conclusions derived from criteria used to assess local equilibrium assumption applicability and indicate that knowledge of reaction kinetics and convective velocities can be easily used to identify conditions conducive to nonequilibrium transport. -from Authors