Modeling Phytoremediation of Soils

Abstract

A numerical model that determines the uptake of cadmium by plants grown to remediate contaminated soils is developed in this study. The numerical model is first applied to the problem of copper uptake from contaminated soils by poplar trees and the simulated results are then validated against published field data. In the numerical model, the one-dimensional Richards equation with a root extraction term coupled with the solute transport equation yields a set of partial differential equations that are solved numerically by a finite element technique. The cadmium uptake is assumed to follow Michaelis–Menton (Monod) kinetics. The nonlinear equations are solved using the Gauss elimination method to determine the temporal and spatial changes in moisture content and heavy metal concentration within the soil profile. The total amount of metal uptake by the plant roots is also computed. A comparison of simulated and field results of copper uptake by poplar trees shows that the model matches very well with the field data. The numerical model developed in this study can be thus used to predict the uptake of metals from soils using appropriate water extraction and the solute uptake functions.