A green alternative for degradation of trihalomethanes by nanocompounds and the use of bioassays to monitor genotoxic effects

Abstract

Trihalomethanes (THMs) are undesirable contaminants that are generated during the pre-chlorination of water in water treatment stations which have been classified by international agencies as carcinogenic to humans. In this study, a green method for degradation of THMs in water via heterogeneous Fenton-like process catalyzed by cobalt-doped magnenite (Fe3-xCox4) was proposed. The determination of THMs degradation efficiencies by liquid-liquid extraction and gas chromatography–mass spectrometry revealed that under optimized conditions (THMs concentration of 240 μg L−1, pH 6, 400 mg of Fe3-xCox4 nanoparticles, and 400 μL of H2O2 (30%)), the proposed procedure was able to degrade THMs (trichloromethane (90%), bromodichloromethane (90%), bibromochloromethane (87%), and tribrommethane (86%)). The remain concentration of THMs were lower than value permitted in water intended for human consumption on Brazil (100 μg L−1). Genotoxicity, mutagenicity, and cytotoxicity tests were also carried out using the organic compounds under investigation, with the plant Allium cepa as a test subject. From the results obtained, it was concluded that the studied contaminants may present both genotoxic and mutagenic effects to exposed organisms. Through this study, it was possible to verify that the method developed has the potential to be used for environmental remediation.