Heavy metal pollution in the surrounding ore deposits and mining activity: a case study from Koyulhisar (Sivas-Turkey)

The oxidation of sulfide minerals generates acidic waters containing high levels of SO₄ and Fe. The study area has active Pb–Zn–Cu mining. It is thought that the surface/subsurface/underground sulfide minerals in the region generally contribute to the acidification of groundwater. Low pH values are also responsible for dissolved metals (Al, Fe, Mn, SO₄, Pb, Zn) in the groundwater and river. Furthermore, current mining wastes have affected concentrations of trace elements in the water. High Fe and Mn concentrations are generally found in the spring which has acidic and low Eh values, while Al, Fe and Mn concentrations in the acidic waters show notable increases with the maximum values reaching 8,829, 19,084 and 1,708 ppb, respectively. These values exceed the Turkish drinking water standard of 200, 200 and 50 ppb, respectively.