Riverfront utilization structure shapes polycyclic aromatic hydrocarbon risks in the middle-lower Yangtze river

The escalating influx of organic pollutants poses a growing threat to aquatic ecosystem integrity in large rivers, underscoring the critical sustainability challenge of mitigating riverine contamination. As persistent anthropogenic tracers, polycyclic aromatic hydrocarbons (PAHs) serve as reliable indicators of human industrial and urban activities, offering critical insights into the rationality of riverfront zoning and industrial configurations guiding green, low-carbon pollution governance. This study investigates the spatiotemporal dynamics of PAHs across the middle-lower Yangtze River, revealing dissolved and suspended particulate matter (SPM)-bound PAH concentrations ranging from 32.7 to 1505.3 ng/L and 22.5-1723.9 ng/L, with marked wet-season elevation in southern banks and downstream. The ecological risk assessment identified medium- and high-molecular-weight (MMW/HMW) PAHs as posing significant ecological risks to aquatic biota. Multivariate analyses indicated that the type of riverfront utilization, particularly industry and port riverfronts, drives PAH risks in the Yangtze River's aquatic environment. This not only directly impacts PAH dispersion but also affects energy consumption, water quality, and chemical plants, thereby driving spatial heterogeneity of PAH risks. Addressing these complex issues necessitates a comprehensive strategy for pollution control and resource management, focusing on optimizing riverfront utilization and promoting industrial upgrades to foster sustainable development of the Yangtze River.