Hydrophobic organic compounds in drinking water reservoirs: Toxic effects of chlorination and protective effects of dietary antioxidants against disinfection by-products

Abstract This study investigated formation and genotoxicities of disinfection by-products (DBPs) during chlorination of hydrophobic organic compounds (HOCs) extracted from six drinking water reservoirs around the Pearl River Delta region, China. Chemical analyses firstly showed that after chlorination aromatic HOCs (including polycyclic aromatic hydrocarbons, PAHs) decreased but DBPs (including chlorinated PAHs) increased, while genotoxicity assays revealed that the chlorination increased DNA damage in human Caco-2 cells. Although the link between DBPs and the genotoxicity was weak (insignificant correlations, p ≥ 0.05), we observed that chlorination of HOCs from more contaminated reservoirs in general resulted in higher genotoxicity. Secondly, remedial effects of catalase and dietary antioxidants (i.e. vitamin C and epigallocatechin gallate) in protecting cells against DBPs genotoxicity were detected. After 1 h treatment by the antioxidants, the DNA damage in Caco-2 cells (due to previous exposure to DBPs) significantly decreased (p