Accumulation of elements in vegetation spontaneously developing on self-heating waste dumps in the Upper Silesia area (Poland)

Abstract

Accumulation of 34 trace and major elements was analysed in 9 plant species (Tussilago farfara, Arctium tomentosum, Solidago canadensis, Populus L., Eupatorium cannabinum, Verbascum sp., Solanum nigrum, Rumex crispus L., Betula pendula) and one fungus (Schizophyllum commune) collected from coal, PbZn-smelting, and mixed-type waste heaps in Upper Silesia (Poland). The most persistent and extreme enrichment was found in the burnt bark of Betula pendula from Bytom. Enrichment factors in relation to the geometric mean of elevated (PE) and hyperaccumulator (PH) plant contents show extreme values for elements toxic to vegetation, such as Zn (EFPE up to 13, EFPH up to 17), Pb (EFPH up to 4, EFPE up to 161), Tl (EFPE up to 8), Cd (EFmax of 327), Hg (EFPH up to 3), and Ag (maximum EFPE of 14). Elevated are also V (EFPN up to 13), Sc (EFPN up to 14), Ni (EFPN up to 17), Se (EFPN up to 16), Fe (EFPN up to 48), Co (EFPN up to 23), Sb (EFPN up to 31), and Bi (EFPN up to 34). Although the levels of the elements studied were usually below potentially toxic levels, they were often above the normal ones. Furthermore, significant differences in the contents between different plant tissues were observed, as reflected in the translocation factor (TF). Verbascum sp. and S. nigrum accumulate such elements mostly in their above-ground tissues, and may thus be considered useful in phytoextraction of Zn, Pb and other elements. Sl. canadensis and E. cannabinum mostly display the opposite strategy, with element immobilization in their roots. Extreme Zn contents in E. cannabinum, peaking in its roots, suggest it to be a potential Zn phytostabilizer.