Novel macromolecular synthetic phenolic antioxidants in sludge on a national scale in China : Their distribution, potential transformation products, and ecological risk

To fulfill the growing demand for retarding the oxidation of polymers and minimizing their migration from various products, new macromolecular synthetic phenolic antioxidants (SPAs) have emerged in the market. There is a concern that these SPAs may be released into wastewater streams during their manufacturing and use, eventually ending up in wastewater treatment plants (WWTPs). Nevertheless, information regarding the occurrence of these SPAs in sludge, particularly on a national scale, is scarce. In this study, several macromolecular SPAs and their transformation products (TPs) were investigated in sludge samples from 45 Chinese municipal WWTPs. All 14 analytes were detected in the sludge samples, among which, 12 analytes were first reported in sludge. 2,4,6-tri-tert-butylphenol (AO246) and 2 macromolecular SPAs, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate] (AO1010) and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate (AO1076), were the most dominant SPAs, with geometric mean (GM) concentrations of 547, 212, and 35.2 ng/g dw, respectively. Two TPs, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoic acid (fenozan) and 3,5-di-tert-butyl-4-hydroxybenzoic acid (BHT-COOH), were found in some sludge samples (48.9-71.1 %) with GM of 45.5 and 12.8 ng/g dw, respectively. By using LC-Q-TOF-MS/MS analysis, we tentatively identified previously unknown TPs of 10 macromolecular SPAs in sludge. This suggests that there are still unclear mechanisms modulating the transformation of these SPAs, which underscores the complexity of their fate. Additionally, using the freshwater photobacteria Vibrio qinghaiensis sp.-Q67 (Q67) as model organism, the acute and chronic EC50 of the 14 analytes were assessed for ecological risk assessment. By considering toxicity data obtained from algae, daphnia, and fish collected or predicted from various databases, we found that these analytes, including their mixture at low detected concentrations, pose risks to aqua
Funding agencies:National Key Research and Development Program of China 2020YFA0907500National Natural Science Foundation of China (NSFC) 22225605 21906179 22193051K.C. Wong Education Foundation of China GJTD-2020-03Foundation of Key Laboratory of Yangtze River Water Environment, Ministry of Education (Tongji University), China YRWEF202201Research Funds of Hangzhou Institute for Advanced Study, UCAS 2022ZZ01017