The Chemistry of Waters Associated with Metal Mining in Macedonia

Abstract  Pollution from current and past mining is a significant problem in several parts of the former Yugoslav Republic of Macedonia. Water from six different mining areas in Macedonia was analysed to assess the effects of metalliferous mining activities. Drainage sediments at all locations show evidence of physical and chemical contamination; water compositions, however, were more variable. Low pH water associated with mining has led to the dissolution of minerals and the mobilization of metals from the ores and the host rocks. Only Sb was noted to exhibit enhanced mobility in higher pH waters. The Zletevo Pb-Zn mine discharges low pH water that has high levels of several metals, including Al, Zn, Cd, and Fe; sediment concentrations are grossly elevated for several km downstream. Toranica and Sasa Pb-Zn mines exhibit similar sediment contamination of Pb, Zn, Cd, and other ore-related metals. However, concentrations of metals in waters are far lower at both of these mines, due to less pyrite in the ore and the buffering of the acid waters by carbonate host lithologies. At the Buchim copper mine, waters are both acidic and high in dissolved solids; Cu concentrations exceed 100 mg/L. Krstov Dol and Alshar are small, disused As-Sb mines that discharge waters that exceed potable values for some contaminants (e. g. As), but this may be related to the mineralization of the bedrock rather than the mines. In general, metal concentrations decreased downstream from the source due to dilution from other rivers and coprecipitation of metals on other mineral phases (e. g. Fe-, Al- and Mn-oxides, and hydroxides).