Heavy metal contamination in groundwater and surface water due to active Pb-Zn-Cu mine tails and water-rock interactions: A case study from the Küre mine area (Turkey)

Authors: TÜLAY EKEMEN KESKİN, EMRE ÖZLER

Abstract: This study aimed at elucidating the groundwater and surface water pollution resulting from water-rock interaction, mine tailings, and mining activities at Küre (Kastamonu) sulfidic Pb-Zn-Cu mine area and its vicinity. The study area has a surface area of approximately 2990 km². The Küre River drainage site covering the study area is approximately 440 km². The concentrations of SO₄, Al, As, Ba, Mn, Ni, Sb, and Pb in some groundwater (K10, K20, K21, K27, K28, K29, K30), and surface water (KR3) exceed the maximum limit values with respect to the Turkish Standards for Water Intended For Human Consumption and World Health Organization Standards. The most polluted waters were K10, K27, and KR3. The K10 well was drilled for observation at the edge of the liquid mine tailing pond of the Küre Pb-Zn-Cu mine area. The K27 well was opened in alluvium outside of the study area and it cuts the clastic units and Mesozoic ophiolites. The KR3 measurement point is located on the Ersizler River, which drains the Küre Pb-Zn-Cu mining site and its dumps. The SO₄, Al, As, Pb, and Sb concentrations of the K10, K27, and KR3 waters were 29.3, 0.8, and 15.1 meq/L; 1135, 1112, and 1186 ppb; 284, 255, and 271 ppb; 19.1, 19, and 18.5 ppb; and 18.7, 17.4, and 19.3 ppb, respectively, in the dry period. As revealed by the analysis, the study area had dual pollution source natural pollution caused by water-rock interactions (K27 and others) and anthropogenic pollution (K10 and KR3) caused by the mine tailings. Furthermore, the K10 water had high tritium (³H)-high electrical conductivity (EC) values that likely indicated anthropogenic contamination. The K27 water had low ³H-high EC values, presumably referring to geogenic contamination. The current study also demonstrated that there was leakage from the liquid mine tailing pond into the groundwater (K10), possibly implying discharge of the liquid mine tailings into the river (KR3).

Keywords: Water pollution, mineral-water interaction, Pb-Zn-Cu mine areas, mine tailings, Küre (Kastamonu)

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