o:8855 Assessment of polycyclic aromatic hydrocarbons pollution in Danube River sediments across Serbia: sources and ecological risk en This study presents a 13-year (2012–2024) assessment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the Serbian Danube River (rkm 1112–864). A total of 132 sediment samples were collected during spring and autumn at seven sites, extracted via Accelerated Solvent Extraction (ASE), and analyzed by GC–MS. Total concentrations of 16 priority PAHs (Σ16PAHs) ranged from 33.4 to 1093.4 µg/kg in spring and 32.0–2747.4 µg/kg in autumn, with seasonal averages of 203–467 µg/kg and 269–561 µg/kg, respectively.Four-ring PAHs accounted for 49–81% of total PAHs, and carcinogenic PAHs contributed up to 61% of Σ16PAHs. The highest toxicity equivalent (TEQ) value of 458.3 µg TEQ/kg (S2, September 2016) remained below the Canadian guideline of 600 µg/kg. The sum of 10 PAHs was predominantly below or near the Serbian target value of 1 mg/kg, with autumn exceedances observed at S1 (1260 µg/kg) and S2 (2317 µg/kg). However, all values remained well below the maximum permissible limit of 10 mg/kg. Diagnostic ratios (BaA/(BaA + Chr), Flu/(Flu + Pyr), LMW/HMW) and the dominance of high-molecular-weight PAHs indicate predominantly pyrolytic sources, mainly coal and biomass combustion. TEQ values declined after 2019, suggesting reduced emissions. Overall, sediments are classified as low to moderately contaminated, with low to moderate ecological risks. This study provides updated long-term data for the central Serbian section of the Danube River, addressing a knowledge gap resulting from the limited temporal and spatial coverage of previous PAH studies, and highlights the importance of systematic monitoring and assessment of individual PAH distributions to evaluate trends and ecological risks. PAHs, Danube River, Sediments, Long-term monitoring, Source apportionment, Ecological risk assessment 1552099 10.1007/s10653-025-02921-y 1552101 0269-4042 2025-12-25T12:08:12.949Z 44 no 46 Tanja Nenin Jaroslav Černi Water Institute, Belgrade, Serbia Marija Perović Jaroslav Černi Water Institute, Belgrade, Serbia person 0000-0003-2045-001X Nebojša Vuković Belgrade City Institute of Public Health, Belgrade, Serbia person Tatjana Mitrović Institute of Physics, University of Belgrade, Belgrade, Serbia person 0000-0002-5991-1445 application/pdf 1518755 https://unilib.phaidrabg.rs/o:8855 no yes 1 70 92000001 71A04 Environmental Geochemistry and Health 48 56 1 18 Springer Nature, Dordrecht, Netherlands 2026 Received: 25 July 2025 Accepted: 25 November 2025 Published online: 17 December 2025