TRACE METAL POLLUTION IN WATERS FROM THE ACTIVE AND ABANDONED MASSIVE SULFIDE DEPOSITS AND WASTES AROUND GIRESUN, TURKEY
The tectonically controlled fossil VMS deposits hosted in the Maastrichtian-Eocene magmatic rocks are either active or have been abandoned hundreds years ago. The main ore mineral assemblages are chalcopyrite, sphalerite, galena, and pyrite. The oxidation of the sulfide minerals in the deposits and wastes has caused to acid mine drainage (AMD) and the effect of AMD continues.
Most of the spring, stream and leakage waters have a strongly acidic pH and high sulfate content, and concentrations of Pb, Zn, Fe, and Cu can reach extremely high values. In addition to these elements, the concentrations of Cd, As, Mo, Se, Sb, Tl, and Bi are higher than the international and national drinking water guideline limits. Iron, aluminum, and zinc levels in stream, spring and leakage waters are enormously higher than those of the rivers. The high concentrations of toxic elements, mainly in the stream and leakage waters, are above the WHO-specified maximum acceptable level in drinking water. The risk index values of toxic elements, in the river water shows no or low risk, while most of the stream, spring and leakage waters show high and/or extremely high risk values. The concentration of the metals and pollution levels of most of the stream, spring and leakage waters may pose environmental risks and they cause disturbances brought to the living things in the area.