Journal of Contaminant Hydrology, cilt.277, 2026 (SCI-Expanded, Scopus)
This study investigates the spatiotemporal variations of toxic metals (Cu, Pb, Zn, Ni, As) in both suspended particulate matter (SPM) and surface sediments of the Borçka Reservoir (Türkiye) to trace pollution dynamics and evaluate ecological risks. The Borçka Reservoir, located in the southeastern Black Sea basin, is an ecologically and hydrologically important freshwater system affected by intensive human activities. Seasonal sampling was performed at four representative stations throughout 2023. The highest metal enrichment was observed in the upstream region, particularly during autumn, indicating the influence of inflowing waters from the Murgul Stream, a major tributary draining mining areas and discharging into the reservoir. Maximum sediment concentrations reached 446.5 μg/g for Cu, 170.7 μg/g for Pb, and 356.33 μ/kg for Zn, exceeding the Probable Effect Level (PEL; Cu: 197, Pb: 91.3, Zn: 315 μg/g) and Effect Range Median (ERM; Cu: 270, Pb: 218, Zn: 410 μg/g) thresholds of sediment quality guidelines. Enrichment and contamination factors classified Cu as “extremely severe” (class 6), while ecological risk (Er) and toxic risk (TRI) values revealed moderate to considerable risks for Cu and Pb. In SPM, metals also showed autumnal peaks. Physicochemical parameters (pH: 8.17–8.53; TOC: 0.52–0.93%) strongly influenced metal retention. The integrated assessment highlights spatiotemporal heterogeneity of metal pollution and emphasizes the need for continuous monitoring and source-based management strategies for sustainable reservoir ecosystems.