Impact of carbonate-hosted Zn-Pb ore deposits on groundwater chemistry: Üzümcü-Olgunlar Mining Site (Hakkari, Türkiye)

Hakkari, known for its high economic value Zn-Pb deposits in Türkiye, has been predominantly producing Zn ore for about 20 years. This study investigated the hydrogeochemical properties of groundwater and surface water collected from the vicinity of carbonate-oxide Zn-Pb mine sites in southern Hakkari to evaluate the effects of mineral deposits and mining activities on groundwater chemistry, as there are potential sources of natural pollution. Samples were collected four times at regular intervals during 2021–2022 from points determined upstream, downstream, and around the mine sites, springs, and streams. The samples were analyzed for majorions, trace elements, and isotopes (18O, 2H, 3H).The waters were in the calcium-bicarbonate facies and the measured metal concentrations in the samples were below the World Health Organization and TS266 drinking water limit values, except for Pb (>10 μg/L) in the waters taken in May 2022. However, hydrogeochemical assessments indicated that samples taken around the mine sites naturally have higher metal concentrations than the others. The low concentration of heavy metals in the groundwater is primarily explained by the low amount of sulfide minerals in the ore and the widespread presence of carbonate rocks to neutralize acids that may originate from sulfate oxidation in the region. Studieson groundwater chemistry around carbonate Pb-Zn mining areas often focus on the SO42– concentration because it reflects the degree of sulfur oxidation even after metals have been removed due to neutralization. However, since the mining areas in the study site were mostly characterized by oxidized Zn-Pb minerals, there was no correlation found between the metals and SO42– concentrations, unlike in other studies.