The concentrations of major and minor elements were determined in the surface water in different parts of the waste processing system (sludge pond, precipitation pits, and drainage streams) of the tailings dumps of a Pb-Zn ore processing plant. The proportions of various forms of migration of heavy metals (Zn, Pb, Cu, Cd, and Fe) and the extent of enrichment of bottom sediments in these elements were estimated for every part of the system. All elements, except for Cu, generally migrate in particulate form. Zinc is most mobile and Pb is the least mobile in these conditions. Correspondingly, despite a high proportion of its migration in particulate form (up to 60%), Pb shows low concentrations in the stream bottom sediments. Stepwise leaching of bottom sediments revealed water-soluble copper forms and heavy metal precipitation by adsorption. It is suggested that a relatively insignificant contribution of toxic element migration with water to the environmental pollution of the studied region with a high anthropogenic impact is related to the high pH-buffering potential of limestones and dolomites hosting the Salair ore field and the reducing impact of industrial run-off.
