The influence of soil organic matter content on soil surface charge and cadmium mobility in soil

Rapid solute and particle transport in structured soils may be reduced by adsorption of ions and chemical material on soil adsorption sites. The influence of soil organic matter content on cadmium adsorption onto soil adsorption sites was studied for chernozem soils of the Danubian Lowland in equilibrium batch experiments (pH 3.5, 7.0, 9.0). The back-titration method was employed to obtain pH-dependent surface charge in conjunction with a potentiometric titration method. The soil surface charge and amount of Cd adsorbed increased with increasing organic carbon content. The experiments enable the prediction of the effect of changes of soil surface properties on cadmium transport in soil.