Aquatic and terrestrial plant species with potential to remove heavy metals from storm-water.

Remediation of storm-water polluted with heavy metals should be possible in percolation systems, ponds, or wetlands. The aim of this work was to find plant species for such systems that are efficient in the uptake of Zn, Cu, Cd, and Pb. Plants were collected from percolation and wetland areas and analyzed for heavy metal concentrations. Results showed that submersed and free-floating plants had the capacity to take up high levels of Cu, Zn, and Pb into their shoots. With roots having a concentration factor above 1, the terrestrial plants show efficient stabilization of Cd and Zn and emergent plants show corresponding stabilisation of Zn. In addition, Potamogeton natans, Alisma plantago-aquatica, and Filipendula ulmaria were used in a controlled experiment. The shoots of P. natans and the roots of A. plantago-aquatica were found to accumulate even higher concentrations of Zn, Cu, and Pb than found in the field-harvested plants. Similar results were found for Cd in shoots and Pb in roots of F. ulmaria. Our conclusion is that submersed plant species seem to be the most efficient for removal of heavy metals from storm-water.