Toxic element contamination in waters from the massive sulfide deposits and wastes around Giresun, Turkey

Abstract

This study assessed the quality of water polluted with mine drainage waters, some of which is used for drinking and agriculture, in the urban areas of the Giresun region, Turkey. A total of 40 water samples were collected from the main rivers and stream, spring, and drainage waters. All samples were analyzed for physical and chemical parameters. The tectonically controlled massive sulfide deposits hosted in the Maastrichtian-Eocene magmatic rocks are either active or have been abandoned. The main ore mineral assemblages are chalcopyrite, sphalerite, galena, and pyrite. The oxidation of the sulfide minerals in the deposits and wastes has caused acid mine drainage (AMD). Most of the spring, stream, and drainage 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. Fe, Al, and Zn levels in stream, spring, and drainage waters are substantially higher than those in the rivers. The risk index values of hazardous elements in the river water show no or low risk, while most of the stream, spring, and drainage waters show high and/or extremely high risk values. The concentrations of the metals and pollution levels of most of the stream, spring, and drainage waters may pose great environmental risks through the changes they cause and disturbances brought to the living things in the area.