Selenium transport and transformation modelling in soil columns and ground water contamination prediction

Selenium transport and transformation were simulated in a soil column. A one-dimensional dynamic mathematical and computer model is formulated to simulate, selenate, selenite, selenomethionine, organic selenium, and gaseous selenium. This computer model is based on the mass balance equation, including convective transport, dispersive transport, surface adsorption, oxidation and reduction, volatilization, chemical and biological transformation. The mathematical solution is obtained by the finite difference implicit method. The model was verified by comparison of model results with experimental measurements and also using mass balance calculations in each time step of calculation. For example after 4 days of simulation, the simulated value of adsorbed selenate for depth of 20 cm is 0.2 mu mol kg(-1) and the measured value is 0.25 mu mol kg(-1). Therefore simulated results are in good agreement with measured values. With this study and its results the distribution of various forms of selenium in soil column to ground water table can be predicted. Copyright (c) 2008 John Wiley & Sons, Ltd.