SEMINAR: Soil and Water Seminar Series 2010 (SEE)

Abstract: Potential leaching of metal pollutants in soils is an important issue in environmental risk assessment. The studies investigated the influence of soil solution processes on metal mobilization, especially when plants are involved and when the amount and the composition of the irrigation water changes.

Special suction cups were installed at vertical distances of a few cm in large soil columns to continuously obtain soil solution samples with high spatial resolution through the soil profile minimizing disturbing the experimental system. The concentration profiles of soil-borne DOC, Cu, Zn and other solutes were measured at various irrigation rates with synthetic rain water under quasi steady-state conditions, using repacked soil columns with a metal-polluted topsoil and two unpolluted subsoils. Labile Zn and Cu2+ concentrations were measured by electrochemistry methods and also were predicted by the NICA-Donnan model with the known concentrations of major cations and anions in soil solution.

The findings in those column experiments were focused on the coupled mobilization of dissolved organic matter and metals (Cu and Zn), the effects of plants on the metal mobilization, and the mobilization of these metals as the soil columns were percolated by different irrigation solutions. Thus, the results of our study highlighted the value of column experiments with high-spatial-resolution sampling in investigating the processes involved in metal mobilization in soil profiles over long time. ------- All Welcome!