Organic micropollutants in surface water across China: Occurrence and ecological risk

• Nationwide suspect screening investigation on hydrophobic micropollutants in surface water . • The main hydrophobic contaminants across China were PAEs , PAHs and OCPs. • Newly reported geographical distributions of multiclass hydrophobic micropollutants. • PAEs and PAHs prioritized in risk assessment by Toxpi and risk quotient. Organic pollutants in surface water present considerable risks to aquatic ecosystems and human health. However, current screening efforts in surface water tend to focus on specific areas. To address this gap, we conducted a nationwide survey to elucidate the prevalence of hydrophobic micropollutants in surface water via gas chromatography Orbitrap mass spectrometry-based suspect screening analysis. The study identified and quantified 91 organic micropollutants across 13 categories. Phthalate ester (PAE) concentrations (median: 1405.33 ng/L) in surface water significantly exceeded those of other pollutants, followed by polycyclic aromatic hydrocarbons (PAHs) and organic chlorinated pesticides (OCPs). Notably, polychlorinated dibenzofuran precursors and Cl-PAHs were newly discovered in water samples across China, for which data were extremely limited. The identified pollutants exhibited distinct north-south disparities and variations across the six major river basins. Toxicological priority index indicated that permethrin demonstrated the highest toxicity, and dibutyl phthalate exerted the greatest risk index. Notably, fifteen compounds had risk quotients exceeding 1, signifying substantial ecological risk, with captafol, a previously unreported OCPs, exhibiting high risk. These findings offer crucial insights for water quality assessment and the management of hydrophobic organic pollutants in surface water across China.