CC-BY-NC-NDĐorđievski, StefanRadojević, AnaKalinović, TanjaNujkić, MajaKalinović, JelenaJordanović, JelenaKovačević, RenataOgawa, Yasumasa2025-12-082025-12-082025978-86-6305-164-510.5937/IOC25678Dhttps://ioc.tfbor.bg.ac.rs/public/2025/Proceedings_IOC_2025.pdfhttps://repozitorijum.tfbor.bg.ac.rs/handle/123456789/6037This study assessed copper contamination and availability in riverbed sediments from 181 locations in Eastern Serbia. The highest total Cu concentrations (up to 26,400 mg/kg) with HCl-extractable fractions up to 80% were recorded downstream of the confluence of Bela and Timok Rivers, where secondary, highly labile copper phases dominated. In contrast, 145 of 181 samples contained <50% 0.5 M HCl-extracted Cu, indicating limited mobility. The findings highlight the need to assess both metal concentrations and speciation to evaluate ecological risk and guide site-specific management.enCopperRiverbed sedimentsBioavailabilityExtractionconferenceObject