Akademik Veri Yönetim Sistemi
Regional Studies in Marine Science, cilt.97, 2026 (SCI-Expanded, Scopus)
Heavy metal accumulation in coastal sediments is strongly influenced by riverine inputs, sediment grain size, and anthropogenic pressures. However, grain-size-resolved assessments remain limited for the southeastern Black Sea coastal systems. This study evaluated the distribution, grain-size-dependent accumulation, and ecological risk of toxic metals (Cu, Pb, Zn, Ni, As, and Cr) in coastal sediments influenced by the Aksu (Giresun), Değirmendere (Trabzon), Fırtına (Rize), and Sundura (Artvin) river discharges along the eastern Black Sea coast of Türkiye. Sediment samples collected during May–June 2024 from four stations in each region were separated into four grain-size fractions (F1: <0.063 mm, F2: 0.063–0.125 mm, F3: 0.125–0.25 mm, and F4: 0.25–0.5 mm). Metal concentrations, physicochemical parameters, total organic carbon, and contamination indices (SEF, Igeo, Er) were analyzed. Metal concentrations increased with decreasing grain size, with the finest fraction (<0.063 mm) acting as the main accumulation phase. In the finest fraction (F1, <0.063 mm), concentrations ranged from 52.3 to 87.5 µg/g for Cu, 40.4–71.1 µg/g for Pb, 100.3–139.8 µg/g for Zn, 39.9–52.7 µg/g for Ni, 10.3–16.6 µg/g for As, and 27.9–36.3 µg/g for Cr. Metal levels generally increased eastward from Giresun to Artvin, reflecting watershed characteristics, geological background, and anthropogenic influences, with higher concentrations at deeper fine-sediment depositional zones. Index-based assessments indicated mostly low to moderate contamination and ecological risk, with relatively higher enrichment observed along the Artvin coast, although relatively higher enrichment occurred along the Artvin coast. Overall, the findings highlight the importance of grain-specific evaluations for accurate assessment of coastal metal accumulation and provide valuable baseline data for environmental monitoring and sustainable coastal management in river-influenced Black Sea ecosystems.