Modeling Heavy Metal (Cadmium) Uptake by Soil‐Plant Root System

Abstract

Among various toxic substances that contaminate plants and enter the food chain, thereby posing health problems to human beings, heavy metals are particularly severe in their action. The behavior of heavy metals present in sewage sludge and industrial wastes that are used in agricultural practices has been the center of much attention during the last decade. Among these heavy metals, cadmium has been identified as the most critical metal due to its human toxicity. The presence of cadmium and its accumulation in the plant root zone also results in decreased crop yield. This study develops a methodology to simulate the transport of cadmium in soil water and its uptake by plant roots. The transient unsaturated water flow equation with a root extraction term is coupled with mass transport equation and mass balance of solute concentration. The model takes into account the root growth with time. The macroscopic root‐soil water flow and solute (cadmium) movement model yields a set of partial differential equations that can be solved using numerical techniques for a given set of initial and boundary conditions.