High concentrations of heavy metals in beech forest understory plants growing on waste heaps left by Zn-Pb ore mining

•High contents of As, Cd, Pb and Zn, but not Tl, were found in soils from waste heaps.•Contents of Cd, Pb, Tl and Zn in tissues of forest plant species from heaps were high.•Strategy of metal accumulation in herb plants depended on species and metal identity.•Tl was effectively transferred from soil to roots of all herb species.•Some heavy metals were efficiently translocated to aboveground plant tissue.

This study investigated (1) concentrations of pollutants such as As, Cd, Pb, Tl and Zn, as well as Ca, Fe and Mn, in soils developed on old heaps of waste rock localized in beech forests (2) concentrations of these elements in shoots and roots of forest herbaceous species – Mycelis muralis, Melica nutans and Mercurialis perennis, and in leaves of young Fagus sylvatica trees growing on the heaps (3) ratios of plant/soil and shoot/root concentrations to assess metal accumulation strategy of herb species. Total soil concentrations of all pollutants except Tl were high, up to 156 mg As kg− 1, 62.9 mg Cd kg− 1, 2853 mg Pb kg− 1, 3.6 mg Tl kg− 1 and 13,508 mg Zn kg− 1. Element concentrations in the tissues of herbaceous plants depended on plant species and organ (shoot vs. root). Cd, Pb, Tl and Zn, but not As, were elevated in both herb species and F. sylvatica in comparison to reference values, reaching up to 0.21 mg As kg− 1, 47.4 mg Pb kg− 1 and 8.2 mg Tl kg− 1 in roots of M. perennis, and 63.6 mg Cd kg− 1 and 752 mg Zn kg− 1 in roots of M. nutans. The efficiency of pollutant transfer from soil to roots and/or shoots varied among plant species and elements. Some heavy metals were effectively taken up from soil (Cd, Tl) or translocated to shoots (Cd, Zn), though it depended on plant species. Our study indicates a risk of the dispersion of heavy metals in the environment.