Phytoremediation potential of transplanted bare-root seedlings of trees for lead/zinc and copper mine tailings.

Selecting plant species that can overcome unfavorable conditions and increase the recovery of degraded mined lands remains a challenge. A pot experiment was conducted to evaluate the feasibility of using transplanted tree seedlings for the phytoremediation of lead/zinc and copper mine tailings. One-year-old bare-root of woody species (Rhus chinensis Mill, Quercus acutissima Carruth, Liquidambar formosana Hance, Vitex trifolia Linn. var. simplicifolia Cham, Lespedeza cuneata and Amorpha fruticosa Linn) were transplanted into pots with mine tailings and tested as potential metal-tolerant plants. Seedling survival, plant growth, root trait, nutrient uptake, and metal accumulation and translocation were assessed. The six species grew in both tailings and showed different tolerance level. A. fruticosa was highly tolerant of Zn, Pb and Cu, and grew normally in both tailings. Metal concentrations were higher in the roots than in the shoots of the six species. All of the species had low bioconcentration and translocation factor values. However, R. chinensis and L. formosana had significantly higher translocation factor values for Pb (0.88) and Zn (1.78) than the other species. The nitrogen-fixing species, A. fruticosa, had the highest tolerance and biomass production, implying that it has great potential in the phytoremediation of tailing areas in southern China.