Testing the Manipulation of Soil Availability of Metals

Manipulating heavy-metal availability with chelating agents is a way to accelerate natural phytoremediation of contaminated soils. Nevertheless, increasing metal availability also increases the risk of metal movement through the soil profile, and consequently the contamination of ground water, exacerbating the environmental problem. Knowledge of metal displacement is, therefore, necessary before attempting manipulations of metal availability at a contaminated site. Experiments done in columns packed with the contaminated soil, to compare effects with and without plants, with and without chelates (e.g., ethylenediaminetetraacetic acid), and with a monitored watering regime, are an easy and feasible way to study different parameters in the soil, plants, and water. Using this method, the utility of the technique for phytoremediation can be tested. Measurements can include, for example, metal content in the leachate, metal movement through the soil profile, metal availability and uptake by plants, and plant growth.