Abstract
Human activities such as metals mining and milling operations provide one of the most important sources of contamination in the environment. Abandoned mines can be an important source of toxic elements. The threat of heavy metal pollution posed by mine soils generally concerns more than one metal.
The aim of this study was to assess total concentration of six potentially toxic metals (Cd, Cr, Cu, Pb, Zn and Fe) in the soil and plant samples of three dominant willow species (Salix purpurea L., Salix caprea L. and Salix eleagnos Scop.) collected from abandoned mixed sulphide mine dumps (Imperina Valley, North-east Italy).
Results demonstrate that metal concentrations in soils are in general above the Italian average limits and they are also significantly (except Cr), as compared with controls (p≤0.05), with averages of 2.12mgCdkg−1, 2267mgCukg−1, 9552mgPbkg−1, 1243mgZnkg−1 and 299,973mgFekg−1.
The phytoremediation ability of selected Salix species for heavy metals was estimated. The results have revealed significant differences among willow species (p≤0.05) regardless of the species selected. The transfer factor and bioaccumulation coefficient of selected metals varied among plant species and from different sites. Some of the investigated species have potential for soil stabilization and extraction of heavy metals. The results indicate that there is an increasing need for further research projects mainly focused on the mechanisms whereby such willows are able to survive in contaminated soils.
► Heavy metal content (Cd, Cu, Pb, Zn & Fe) of soils from an abandoned Italian mining site. ► Flux of potentially toxic elements from soil to wild plants. ► Test the ability of selected Salix spp to accumulate heavy metals in their tissues. ► Willow qualifies as good candidate for phytoremediation of polluted soils.