Toxicity evaluation and by-products identification of triclosan ozonation and chlorination

Triclosan (TCS) has attracted increasing concern due to its ubiquitous occurrence in aquatic environments as well as its potential adverse effects on human health. This study investigated the toxicity and transformation characteristics of triclosan ozonation and chlorination. The results showed that two hydroxylated by-products were formed via nucleophilic substitution during ozonation, while three chlorinated compounds were generated via electrophilic substitution during chlorination. The toxicity results demonstrated that the parent compound, triclosan, exhibited mild genotoxicity and antiestrogenic activity. The chlorination of triclosan resulted in a 30-fold increase in anti-estrogenic activity owing to the generation of toxic polychlorinated transformation by-products. In addition, the chlorination by-products were found to be genotoxic like the parent compound. Fortunately, in contrast to chlorination, ozonation could mitigate the genotoxicity and anti-estrogenic activity of triclosan-containing water. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

The study investigated the toxicity and transformation characteristics of triclosan ozonation and chlorination, revealing the generation of toxic chlorinated compounds during chlorination and the mitigation of genotoxicity with ozonation treatment. Chlorination led to a 30-fold increase in anti-estrogenic activity, while ozonation could reduce the toxicity of triclosan-containing water. Therefore, ozonation may be a more environmentally friendly and safe method for treating triclosan wastewater.