Phytoextraction of cadmium, copper, zinc and mercury by selected plants

During the years 2006 and 2007 the phytoextraction ability of maize (Zea mays), willow-tree (Salix smithiana) and poplar (Populus nigra × P. maximowiczii) to accumulate cadmium, copper, mercury and zinc was investigated. Small scale field experiment was carried out on soil contaminated with chemicals from the waste incineration plant in Hradec Kralové (Czech republic). Screening of this allotment showed very different contamination of all observed risk elements on places where the material intended to be burnt without safety of leakage into soil. Grown plants showed the different accumulation of observed elements in plant tissues as well as the influence of total content of the risk elements in soil. The highest Cd (1.5–1.73 mg/kg) and Zn (242–268 mg/kg) concentrations were found in willow-tree biomass mainly in the leaves. Cu and Hg were mostly accumulated by maize roots (14.6–15.8 mg Cu/kg and 1.3–7.4 mg Hg/kg) and lower amount was found out in willow-tree leaves again. in reference to total production of each plant the maximum Cd and Zn uptake by aboveground biomass was found in poplars (201 mg Cd/m2 and 38 200 mg Zn/m2) and maize, which showed high Zn uptake. The biggest amount of copper (2563 mg Cu/m2) was accumulated by aboveground maize biomass on the collection point with the highest Cu concentration in soil and by poplar (2394 mg Cu/m2) on the other collection point. The highest Hg uptake differs in reference to total Hg content in soil; willow-tree has the highest uptake on the place with lower Hg content in soil (44.6 mg Hg/m2) and maize has the highest uptake on the place with higher Hg content in soil (92 mg Hg/m2).