THE WETLAND GRASS GLYCERIA FLUITANS FOR REVEGETATION OF METAL MINE TAILINGS

Revegetation under wetland rather than dryland conditions provides an alternative to traditional methods of rehabilitation of metal mine tailings. The wetland plant Glyceria fluitans (floating sweetgrass) was found growing in a lead/zinc mine-tailings pond. The potential of this species for revegetation of mine tailings under wetland conditions had not previously been investigated. In two outdoor experiments, G. fluitans of non-contaminated origin grew successfully on alkaline tailings containing elevated metal concentrations (230 μmol g−1 Zn, 11 μmol g−1 Pb). Growth of G. fluitans was significantly enhanced on tailings treated with NPK fertilizer (700 kg ha−1), but the plants grew well even without fertilizer, indicating a low nutrient requirement. Glyceria fluitans did not survive on saline (MgSO4) tailings originating from another mine that contained much higher lead (34 μmol g−1) and iron (2584 μmol g−1) concentrations. The ability of G. fluitans to tolerate many of the adverse conditions associated with mine tailings favors its use for revegetation purposes.