Sources, temporal dynamics, and environmental risks of polycyclic aromatic hydrocarbons and petroleum hydrocarbons in sediments of the Danube, Tisza, and Sava Rivers (Serbia)
摘要
This study presents a twelve-year (2014–2025) integrated assessment of polycyclic aromatic hydrocarbons (PAHs) and total petroleum hydrocarbons (TPH) in surface sediments of the Serbian section of the Danube River and its major tributaries, a key transboundary pathway for pollutant transport to the Black Sea. Beyond routine monitoring, the study combines long-term trend analysis, source apportionment, and toxicity evaluation within a regulatory risk framework. A total of 64 sediment samples were collected during annual campaigns at five sites and analyzed using accelerated solvent extraction (ASE) and gas chromatography–mass spectrometry (GC–MS). Maximum TPH concentrations were observed at Stari Banovci (828.8 mg kg⁻1), while tributaries exhibited elevated PAH levels, reaching 1533.5 μg kg⁻1 in the Tisza River. PAH composition was dominated by four-ring compounds (64–72%), with carcinogenic Σ7PAHs comprising 59.6–76.4% of Σ16PAHs. Toxic equivalency (TEQ) values remained below international sediment quality guideline thresholds. Sediments were classified as low to moderately contaminated, with ecological risk levels predominantly low to medium; however, recurrent elevated risk associated with pyrene was detected at multiple sites and sampling periods, indicating localized but persistent ecological concern. Diagnostic ratios indicated predominantly pyrolytic sources linked to coal and biomass combustion. The integrated analysis reveals spatially heterogeneous contamination, identifies tributaries as major hydrocarbon sources, and highlights large rivers as key pathways to marine environments.