Effects of plants and soil microflora on leaching of zinc from mine tailings

A greenhouse study was conducted to determine whether the concentration of zinc (Zn) in leachate from contaminated soil could be affected by plant, mycorrhizal fungi, or soil bacterial interactions. Zinc uptake by plant roots and Zn concentrations in roots and shoots were lower in plants inoculated with mycorrhizal fungi. The mass of Zn in the leachate was greatest from pots in which plants were grown in the absence of microbial amendments. Although the presence of plants alone increased the average concentration of Zn in the leachates, the presence of soil microbes eliminated this effect. Infection of plant roots with mycorrhizae did not reduce Zn leaching relative to that with plants alone. Results from this study indicate that revegetation of mining waste sites may increase the leaching of Zn, especially when soil microflora have not been fully restored.