Mercury and methylmercury in plants from differently contaminated sites in Slovakia

Concentrations of methylmercury (MeHg) and total mercury (Hgtotal) were investigated in green leaves of herbs, deciduous and coniferous trees in 9 sites in Slovakia (the transect Žiar nad Hronom - Vtáčnik, Banská Štiavnica, Rudňany). There was evaluated the relevance of plant uptake and the behaviour of transfer-factors. The MeHg and Hgtotal in leaves of plants from the contaminated sites in Rudňany (up to 3.21 and 802 ng Hg/g, respectively) were an order of magnitude larger than those from other sites, reflecting the strong Hg contamination in Rudňany's plants. The MeHg and Hgtotal concentrations in leaves (up to 0.285 and 55 ng Hg/g, respectively) from the transect Žiar nad Hronom - Vtáčnik and Banská Štiavnica may be regarded as uncontaminated. The green leaves from Rudňany showed very low transfer-factors (up to 0.09) compared to the transfer-factors from the transect Žiar nad Hronom - Vtáčnik (up to 1.58), and thus indicated the relevance of Hg translocation from soils to leaves on contaminated sites. Generally, much higher MeHg concentrations in leaves of Corylus avellana L., Quercus polycarpa Schur. and Achillea millefolium L. as compared to the other plant species indicate species specific effects that is also confirmed by increased transfer coefficients for relevant leaves (up to 3.48, 2.51 and 0.35, respectively). The transfer-factors can bring up the species specific differences in the Hg uptake by plants.