Anti-epidemic pharmaceuticals predominantly contributed to PPCPs flux in the Yangtze River during 2020.

The COVID-19 pandemic triggered a surge in pharmaceutical consumption, yet its impact on large-scale riverine systems remains poorly quantified. This study investigated the spatiotemporal distribution, sources and transport flux of 58 pharmaceuticals and personal care products (PPCPs) across the Yangtze River Basin (3400 km mainstream and 8 tributaries) during 2020. The mean concentration of PPCPs was 200.2 ± 205.7 ng/L in 2020, with caffeine (28.2 %), carbamazepine (13.2 %), and metronidazole (9.2 %) as dominant compounds. It was estimated that 449.8 tons of PPCPs were discharged into the sea via the Yangtze River in 2020, of which 48 % (216.0 tons) originated from COVID-19-related pharmaceuticals (e.g., metronidazole, diclofenac). Compared to pre-pandemic levels (2018), the river experienced additional pollution pressure from 209.6 tons of COVID-19 related pharmaceutical emissions. Source apportionment identified post-consumer anthropogenic activities (domestic discharges, clinical effluent outflows, and veterinary applications) as primary contributors (p < 0.05), while industrial sources associated with pharmaceutical production contributed little. Low ecological risks were observed in the study area, likely attributable to high wastewater treatment rates (>90 % in most cities) and the high efficacy of centralized wastewater management. This study provided the first basin-scale quantitative evidence of pandemic-driven PPCP pollution, offering critical insights for balancing public health emergencies with sustainable water resource governance.