Contaminated water runoff from dam slopes of tailings pond of flotation plant of Zn-Pb Mississippi Valley-type ores at Bolesław near Olkusz

The paper presents results of studies on storm-generated surface runoff, a phenomenon belonging to the least known factors responsible for migration of pollutants to water environment. The results of determinations of pH, conductivity as well as content of Ca, Zn, Cd, and Pb are found to be useful as the main indicators of pollution spread by waters running from dam slopes of pond in which tailings from flotation of Zn-Pb ore are disposed. Rain water leaches fine fractions of carbonate-sulfate wastes (represented mainly by dolomite, 73%, and Fe sulfides – marcasite, up to 20%) which leads to change in character of surface runoff water to that of SO4-Ca hydro-chemical type. Among the leached metals significantly important for the environment are Zn, Cd and Pb whose concentrations exceed threshold values for surface and/or groundwater of IV quality class. Acceptable concentrations in waste waters are frequently exceeded by sulfates and incidentally by zinc. Variability of the analyzed concentration indices from the years 2008 and 2009 indicates influence of weather conditions on chemical composition of surface runoff water from slopes of tailings pond of flotation plant of MVT ores