Dominant Plant Species And Their Heavy Metal Uptake In Typical Lead-zinc Mine Areas

Soil heavy metal contamination is an important environmental problem worldwide and there is considerable interest in the remediation of polluted sites. Phytoremediation is an emerging technique for the cleanup of heavy metal polluted soils and offers the potential benefits of being performed in situ, cost-effectiveness and environmental sustainability. There have been many studies on the use accumulator or hyperaccumulator plants for phytoextraction. The success of phytoextraction depends on several factors, including the discovery, identification and growth of suitable plants. In the present project, metal uptake by the dominant plant species in abandoned lead-zinc mine areas in Zhejiang Province was investigated. Hydroponic culture and glasshouse pot experiments were conducted to characterize the tolerance to, and uptake of, heavy metals by one particular species, Sedum alfredii Hance, collected from Fuyang county. Results can be summarized as follows:(1) The soils in the mining areas had high concentrations of heavy metals, with average concentrations in the soils following the sequence Cd < Cu < Pb < Zn and in plants following the order Cu < Cd < Pb < Zn. The dominant plant species were recorded in terms of distribution, genetics and taxonomy. Metal tolerance and uptake, the role and importance of the plant species and future research requirements in the mining areas are also discussed.(2) An new Sedum species was found and was named Sedum plumbizincicola as a distinct taxon. This increases the total number of Sedum species recorded in China to 124.(3) The Fuyang ecotype of Sedum alfredii Hance has very high zinc tolerance, with high shoot concentrations, but does not achieve hyperaccumulation of Zn. Shoot Cd concentrations averaged 814 mg kg-1 when the nutrient solution Cd concentration was 50μmoles per liter.