Fractionation and geochemical mobility of heavy elements in soils of a mining area in northern Kosovo

This paper reports the results of a geochemical study focusing on the partitioning of As, Cd, Cu, Pb, Sb and Zn in soils of the Kosovska Mitrovica mining area in northern Kosovo. The main objective was to define the element mobility in soil and potential bioavailability in relation to soil contamination levels. The Kosovska Mitrovica area is one of the main industrial sites in the former Yugoslavia and a world-class mining district in Europe. Extensive and locally very marked contamination mainly by Pb, Zn, Cd and Sb was found in soils, with the highest concentrations measured close to the Zvecan smelter. The study of As, Cd, Cu, Pb, Sb and Zn partitioning in the water soluble, extractable with 0.11 M acetic acid, reducible, oxidable and residual fractions of soils revealed that Pb was mainly associated with the reducible fraction, Cd with the extractable and reducible fractions, and As, Cu, Sb and Zn with the residual fraction. Heavy element fractionation in contaminated soils was influenced by the presence of owner mineralogical phases related to the emissions of the Zvecan smelter and to materials windborne from mining and industrial dumps, as well as originated by in situ processes. The order of mobility of these heavy elements in contaminated soils resulted as follows: Cd ≫ Zn ≫ Pb ≫ Sb > As > Cu. Anthropogenic amounts of heavy elements were distributed in all soil fractions, with the most relevant enrichments in the extractable and reducible ones. Anthropogenic inputs were responsible for some deviations from natural fractionation, mainly for Pb, Zn and Cd. A significant amount of Cd, Pb and Zn in contaminated soils was rather mobile, which suggests that these elements can be readily available to plants and soil organisms.