Bioakumulacija Pb i Cd u zemljištima livadskih zajednica Agrostietum capillaris (Z. Pavlović 1955) na području Zlatara i Stare planine / Bioaccumulation of Pb and Cd in soils of meadow associations Agrostietum capillaris (Z. Pavlović 1955) on Zlatar and S

The content of microelements in the soil and their accessibility to the plants, depends on various abiotic and biotic factors, but also on certain characteristics of plant species. A high level of translocation and bioaccumulation of some microelements can result from specific forms of metal- organic complexes that are easily transported as well as certain soluble compounds due to organic matter decomposition. The aim of this paper was to determine the degree of uptake, transport and accumulation of Pb and Cd in natural conditions in common bent (Agrostietum capillaris Z. Pavlović 1955) community. Study area were meadow community on the Mt. Stara planina (locality Javor) and Mt. Zlatar (locality Vodena poljana). Soil samples were taken at fixed depths, and physicochemical properties were determined, while parts of aboveground and belowground biomass were taken according to the IPCC methodology. The translocation and bioaccumulation were measured based on factors given by shoot to root ratio of Cd and Pb concentrations in soil, belowground and aboveground biomass. The concentrations of Pb and Cd in the studied soils at both locations are lower than the limit values, but the average Pb content is higher in the area of Zlatar Mt. which is statistically significant. There is a strong correlation between Pb and soil properties on Zlatar Mt, while Cd shows statistically significant relation to soil properties on Stara planina Mt. Pb concentration are higher in belowground biomass compared to the aboveground, with significantly higher concentration on Zlatar Mt. The translocation factor shows that Pb is accumulated in higher content in belowground biomass compared to aboveground, both on Stara planina and Zlatar Mt, but low values of this factor show that there is no translocation process from root to aboveground biomass. Foliar uptake is also known as the source of toxic microelements, from wet deposition. Although Pb is a metal which is mainly accumulated in the roots, its higher concentrations in the belowground biomass on Zlatar Mt may be the result of available Pb forms originating from a cross-border deposition. Pb concentration in aboveground biomass is within the limits of natural concentrations both on Stara planina and Zlatar. Cd concentrations are higher in belowground biomass at both sites, compared to aboveground biomass, as indicated by translocation factor, with values <1. The ratio between belowground biomass and soil shows that TF values are significantly >1 both on Stara planina and Zlatar Mt., which indicates a high level of Cd uptake by plants and its transport to aboveground biomass. However, foliar uptake is also characteristic for Cd, whereby this element is easily transported to the other parts of plants through various forms of metal-organic compounds, and accumulated in the root. As a proof of that process, the values of bioaccumulation factor are significantly higher than 1 at all profiles except one on Zlatar Mt. which is also confirmed by the strong correlation between the content of Cd in the belowground and aboveground biomass.