Spatial and Seasonal Distribution, Source Apportionment, and Risk Assessment of Dissolved-Phase Ultraviolet Absorbents and Synthetic Phenolic and Amino Antioxidants in the Pearl River Delta (PRD), China

The occurrences of antioxidants (AOs) in aquatic environments, including ultraviolet absorbents (UVAs), synthetic phenolic antioxidants (SPAs), and amino antioxidants (AOAs), are receiving concerns due to potential risks to ecosystems and humans. In this study, we systematically elucidated the spatial and seasonal variation, sources, and risk assessments of 4 SPAs, 14 AOAs, and 12 UVAs in surface water in the Pearl River Delta (PRD). The total concentration of AOs (Σ30AOs) displayed significant seasonal trends, with a higher concentration observed in dry seasons. The median concentrations of Σ30AOs were 95 and 42 ng/L for the dry and wet seasons, respectively. BHT-COOH and BHT-OH, DPA and DODPA, and UV-329 were the most abundant SPAs, AOAs, and UVAs, respectively. Strong significant and positive correlations were observed between the population of local residents and concentrations of SPAs and AOAs (p < 0.001), indicating that the occurrences of SPAs and AOAs were influenced by anthropogenic activities. Source apportionment first revealed that AO contamination in the PRD mainly encompassed rubber manufacturing and plastic, resin, and polymer manufacturing, accounting for 61 and 25% of AOs in the PRD. The ecological risks were identified to be high for DODPA while the human health risks were found to have no adverse effects.