Alfalfa Plants

Experiments were performed in a laboratory chamber to investigate the influence of alfalfa plants on the fate and transport of trichloroethylene (TCE) fed at 200 μl/l concentration in the entering ground water. Concentrations of TCE in the aqueous and gas phases were regularly monitored in the chamber. Evapotranspirational fluxes of TCE were also reported from the soil to the headspace of the chamber. Numerical modeling of the fate of TCE in the vertical direction of this chamber was carried out using the Galerkin finite element approach. In this model, the partitioning of TCE between solid, aqueous, and gas phases was represented as rate-independent physical equilibrium processes. The boundary condition at the surface was modified to account for free volatilization of TCE to the headspace of the chamber across a thin atmospheric boundary layer. The simulation results were compared with experimental data on the transport of TCE. Results indicated that the water and air content distribution in the soil significantly impact the transport of TCE in subsurface soils.