Polycyclic Aromatic Hydrocarbons (PAHs) in Freshwater Systems: A Comprehensive Review of Sources, Distribution, and Ecotoxicological Impacts.

This comprehensive review offers new perspectives on the distribution, sources, and ecotoxicological impacts of polycyclic aromatic hydrocarbons (PAHs) in freshwater systems. Unlike previous reviews, this work integrates recent findings on PAH dynamics within environmental matrices and emphasizes spatiotemporal variability across geographic regions. It critically examines both anthropogenic and natural sources, as well as the physical, chemical, and biological mechanisms driving PAH transport and fate. Special attention is given to the ecotoxicological effects of PAHs on freshwater organisms, including bioaccumulation, endocrine disruption, and genotoxicity. Notably, this review identifies key knowledge gaps and proposes an interdisciplinary framework to assess ecological risk and guide effective monitoring and management strategies for the protection of freshwater ecosystems.