Safety assessment of effluents from different drinking water treatment process by genotoxicity test

Using micronucleus tests and comet assays, the genotoxicity of Changjiang River raw water, effluent water from conventional process (flocculation+sedimentation+sand filter), effluent water from enhanced conventional process (flocculation+sedimentation+biological enhanced activity filter), and effluent water from biological activated carbon process (flocculation+sedimentation+sand filter+biological activated carbon filter) are analyzed. The results show that comparing with the control group at dosage of 0.13 to 1.00 L/plate, the frequencies of micronuclei in human peripheral blood lymphocytes induced by Changjiang River raw water, effluent water from conventional processes, and effluent water from conventional processes are significantly increased while that caused by effluent water from biological activated carbon process keeps constant. Besides, DNA damages in human peripheral blood lymphocytes are induced by Changjiang River raw water, effluent water from conventional process, effluent water from enhanced conventional process, exhibiting dose-response relationships respectively. However, with biological activated carbon process, DNA damages are induced only at dosage of 0.5 L/plate. This study demonstrates that micronucleus tests and comet assays can be used for assessment of safety of effluents from different drinking water treatment process.