Mobility of Trace Elements in Agricultural Soils

Abstract

AbstractNumerous studies were published to quantify and model trace elements mobility in soils to understand their fate in the environment. The transport of trace elements is controlled by soil colloid properties, trace element characteristics, and environmental soil conditions. However, the diffusion process and the rate-limited sorption behavior control the retention and mobility of trace elements in soil, especially on the longtime scale. In this chapter, the role of solute transport mechanisms (diffusion and the hydrodynamic dispersion) and the principles of trace elements’ reactivity in soils were reviewed and discussed. Besides, this chapter includes a concise review of using the advection-dispersion equation for quantifying and simulating the mobility of trace elements in soils. The literature review revealed that the combined effects of physical, chemical, equilibrium, and kinetic processes control trace elements mobility in soils. Several studies indicated the importance of considering the nonlinear and the sorption kinetic behavior for modeling trace elements’ mobility in soils. Furthermore, brief discussions of Cd, Cu, Pb, Sn, and Se mobility in agricultural soils were presented. Based on the literature review, further research is needed to explore and model the competitive effect of multiple trace elements on the mobility of each other in the soil systems.KeywordsHeavy metalTransportMiscible displacementSorptionKinetic