Boron Transport in Soils as affected by Dissolved Organic Matter in Treated Sewage Effluent
Interaction of effluent dissolved organic matter (DOM) with native soil organic matter (OM), B complexation with DOM, and adsorption of B by soil all play an important role in assessing B transport in soil. However, no information is available yet on the impact of these reactions on B mobility in soil. The objective of the present study was to evaluate the effect of B-DOM complexation on B mobility in soils irrigated with treated effluents. Soil column displacement experiments were conducted to measure the B mobility in the presence of DOM extracted from municipal treated sewage plants. To describe B transport in the presence of DOM, a traditional multicomponent transport model was used. The model took into account the B-DOM-soil reactions (obtained from batch experiments). It was observed that the presence of OM molecules in soil solution enhanced B transport in soil due to B-OM complexation. The concentration of this complex in soil solution increases with the concentration of the dissolved OM (from both effluent and native soil).The model simulated well the effect of DOM on B transport in soil.