Plankton diversity and its application in water safety evaluation under the background of compound pollution-A case...

This study concentrated on the Qiantang River in Zhejiang Province, undertaking a comprehensive year-long investigation across 40 sites to quantify conventional pollutants, heavy metals, poly- and perfluoroalkyl substances (PFASs), neonicotinoid insecticides (NNIs), and organophosphate esters (OPEs), while also evaluating plankton diversity. A thorough water safety assessment was subsequently developed. The findings revealed significant pollution levels, with total nitrogen identified as the predominant conventional pollutant, alongside elevated concentrations of Fe and Mn in certain areas. The concentrations of ∑PFASs ranged from 31.2 to 1390 ng/L, ∑NNIs from 10.6 to 115 ng/L, and ∑OPEs from 1.15 to 35.9 ng/L. The ecological risk assessment highlighted moderate to high risks associated with perfluorooctanoic acid, perfluorooctanesulfonic acid, and clothianidin, whereas other emerging pollutants were deemed to pose low risks. Zooplankton analysis identified 109 genera/species, exhibiting notable spatial variations, while the phytoplankton community demonstrated stability. The water safety assessment of the Qiantang River indicated a moderately healthy state with regional disparities: the upstream areas were classified as moderately healthy, the middle reaches as stable, and the downstream regions were under pressure from industrialization and urbanization. Biodiversity and water quality enhance water safety, but emerging pollutants have significant negative impacts and need better control.