Occurrence and ecological risks of pharmaceuticals along the Yangtze River Basin of China: Insights from target analysis and suspect screening strategy.

Pharmaceuticals have gained global attention in recent decades due to their substantially growing demand and ecological impacts. This study aimed to comprehensively investigate the pollution status of 64 target pharmaceuticals in water (i.e., dissolved phase), suspended particulate matter, and sediment in the Yangtze River Basin (YRB). Across the three environmental compartments, our results uncovered the presence of 49-58 and 23-62 pharmaceuticals in YRB and Huangpu River (HR), respectively. The downstream area of HR showed significantly higher cumulative concentrations of detected pharmaceuticals compared to the other studied sections in the YRB (p < 0.05), reaching 4995.61 ± 4288.16 ng/L in the dissolved phase. The suspended particulate matter demonstrates a higher capacity to adsorb pharmaceuticals from the dissolved phase in comparison to surface sediment, and the organic carbon content in sediments emerged as a critical factor influencing the distribution behavior of pharmaceuticals. Suspect screening confirmed the presence of 170 compounds in the three environmental compartments, including 26 predicted transformation products found in this study and 144 reported pharmaceuticals and transformation products from previous studies. Based on the toxicological prioritization index score, diclofenac was ranked the top priority chemical of concern. The results underscore the estuary region of YRB as a pollution hotspot that gathers and transports pharmaceutical residues from upstreams into the East China Sea. Moreover, our findings provide a foundation for implementing pollutant control measures and effective environmental management strategies in this densely populated river basin.