Genotoxicity of chlorinated hydrophobic organic compounds extracted from a source of drinking water

• Published in: Ecotoxicology and environmental safety Vol. 267; p. 115598
• Main Authors: Wu, Binbin, Zhang, Yanling, You, Yuehua, Liang, Yan
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 15-11-2023; Elsevier
• Subjects: DNA damage; EROD; Genotoxicity; Hydrophobic organic compounds; ROS; Sediment; EROD; Sediment; DNA damage; Hydrophobic organic compounds; ROS; Genotoxicity
• ISSN: 0147-6513; 1090-2414; 1090-2414
• DOI: 10.1016/j.ecoenv.2023.115598

As precursors of disinfection by-products (DBPs), sediment hydrophobic organic compounds (HPOCs) derived from six reservoirs along the Dongjiang River were chlorinated (Cl-WS) and then fractionated into two polar components (hydrophobic organic compounds (Cl-HOCs) and hydrophilic organic compounds (Cl-HICs)) by solid phase extraction. Based on Caco-2 cell exposure study, the genotoxicity of Cl-WS, Cl-HOCs and Cl-HICs was analyzed by reactive oxygen species (ROS) analysis, comet assay and ethoxyresorufin-O-deethylase assay. Protective effects of antioxidants (catalase, vitamin C and epigallocatechin 3-gallate (EGCG)) on genotoxicity of the chlorinated samples were investigated. The results showed that Cl-WS and its two fractions (Cl-HOCs and Cl-HICs) induced ROS, DNA damage and dioxin-like toxicity (TEQbio), and Cl-HICs were a major contributor to oxidative damage and TEQbio compared with Cl-HOCs. Antioxidants significantly reduced Cl-HOCs- and Cl-HICs-induced ROS, but had insignificant effect on DNA oxidative damage and TEQbio. In addition, EGCG showed higher efficacy in reducing DNA damage induced by Cl-HICs than by Cl-HOCs. To our knowledge, this is the first study to investigate the genotoxicity of Cl-WS and its two polar components in Caco-2 cells, as well as the protective effects of antioxidants on Cl-HOCs and Cl-HICs-induced ROS, DNA damage, and TEQbio. This study provides important toxicity information for water treatment industries in differentiating DBPs of different polarity.
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•Cl-WS and its two fractions, Cl-HOCs and Cl-HICs, induce ROS, DNA damage and dioxin-like toxicity.•Compared with Cl-HOCs, Cl-HICs induces higher oxidative damage.•Some antioxidants selectively reduce ROS induced by Cl-HOCs and Cl-HICs.•EGCG has a higher inhibitory effect on Cl-HICs-induced DNA damage than Cl-HOCs.