Occurrence and potential risks of high-molecular-weight synthetic phenolic antioxidants and long alkyl chain parabens in the Yangtze River basin, China

Synthetic phenolic antioxidants (SPAs) and parabens, particularly the high-molecular-weight (HMW) SPAs and long alkyl chain (LAC) parabens with higher environmental persistence and toxicities, are widely produced and applied worldwide. However, their occurrence and potential risks in aquatic environments remain largely unknown. This work investigated 11 HMW SPAs and 3 LAC parabens in the river and treated industrial wastewater samples along the Yangtze River, the largest river and most important source water in China. For convenience of comparison, 6 short alkyl chain (SAC) parabens were also included. In 15 industrial wastewater treatment plant effluents (effluent-IWTPs) and 34 surface water monitoring sections along the river, 19 out of 20 target compounds were detected with total concentrations (TCs) from 152.5 to 1955.5 ng/L and 141.3 to 1364.9 ng/L in effluent-IWTPs and surface water, respectively. HMW SPAs 1,3,5-tris-[(3,5-di‑tert‑butyl‑4-hydroxyphenyl) methyl]-1,3,5-triazinane-2,4,6-trione (AO3114) and octadecyl 3-(3,5-di‑tert‑butyl‑4-hydroxyphenyl) propionate (AO1076) were the dominant ones. HMW SPAs bis(3‑tert‑butyl‑4‑hydroxy-5-methylphenyl) propionate (AO245) and 4,4′-sulfanediylbis(2‑tert‑butyl‑5-methylphenol) (AO-TBM6) and SAC parabens propylparaben (PrP) and butylparaben (BuP) posed medium to high potential ecological risks in 27 surface water monitoring sections. Additionally, AO-TBM6 also exhibited potential health risks in 2 out of 11 drinking water sources. Though the ecotoxicity data are very limited, the ubiquitous presence of the LAC parabens including hexylparaben (HeP) and octylparaben (OcP) in surface water should be of concern since these compounds usually exhibit stronger estrogen potencies than the SAC ones. Finally, kernel density analysis revealed that regulation of industrial discharges is necessary to mitigate the HMW SPA and paraben contamination.