Javad Nasiri Rajabli, Sayed Ahmad Mirbagheri, Amir Hesam Hasani and Amir Hossein Javid
A two-dimensional finite difference model was developed to simulate species of selenium transport and transformation in two dimensions in both saturated and unsaturated soil zones. This 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 developed model was applied to simulate observed field data. For the validation of model under transient state, the data sets collected from Gonbad-e-Kavous site, Golestan province. The simulated results are in good agreement with measured values. The simulation of the observed data was satisfactory with mean relative error of 4.02%. With this study and its results the distribution of various forms of selenium in soil column to ground water table can be predicted.