title: A soil-plant model applied to phytoremediation of metals.
abstract: This study reports a phytoremediation pot experiment using an open-source program. Unsaturated water flow was described by the Richards' equation and solute transport by the advection-dispersion equation. Sink terms in the governing flow and transport equations accounted for root water and solute uptake, respectively. Experimental data were related to application of Vetiver grass to soil contaminated by metal ions. Sensitivity analysis revealed that due to the specific experimental set-up (bottom flux not allowed), hydraulic model parameters did not influence root water (and contaminant) uptake. In contrast, the results were highly correlated with plant solar radiation interception efficiency (leaf area index). The amounts of metals accumulated in the plant tissue were compared to numerical values of cumulative uptake. Pb(2+) and Zn(2+) uptake was satisfactorily described using a passive model. However, for Ni(2+) and Cd(2+), a specific calibration of the active uptake model was necessary. Calibrated MM parameters for Ni(2+), Cd(2+), and Pb(2+) were compared to values in the literature, generally suggesting lower rates and saturation advance. A parameter (saturation ratio) was introduced to assess the efficiency of contaminant uptake. Numerical analysis, applying actual field conditions, showed the limitation of the active model for being independent of the transpiration rate.
authors.affiliation: a Geotechnical Laboratory, Department of Civil Engineering , Federal University of Rio de Janeiro , Rio de Janeiro, RJ, CEP, Brazil.
authors.forename: Francesco
authors.initials: F
authors.lastname: Lugli
authors.affiliation: a Geotechnical Laboratory, Department of Civil Engineering , Federal University of Rio de Janeiro , Rio de Janeiro, RJ, CEP, Brazil.
authors.forename: Claudio Fernando
authors.initials: CF
authors.lastname: Mahler
mesh_terms: D001673:Biodegradation, Environmental; D008670:Metals / Q000378:metabolism*; D008954:Models, Biological; D018517:Plant Roots / Q000378:metabolism; D006109:Poaceae / Q000378:metabolism*; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000378:metabolism*
chemical_list: D008670:Metals; D012987:Soil; D012989:Soil Pollutants
keywords: active root metal uptake; exclusion; non-linear sorption