Genotoxicity of the disinfection by-products resulting from peracetic acid- or hypochlorite-disinfected sewage wastewater

摘要

Wastewater disinfection is routinely carried out to prevent the spread of human pathogens present in wastewatereffluents. To this aim, chemical and physical treatments are applied to the effluents before their emission in waterbodies. In this study, the influence of two widely used disinfectants, peracetic acid (PAA) and sodium hypochlorite(NaClO), on the formation of mutagenic by-products was investigated. Wastewater samples were collected before andafter disinfection, in winter and in summer, at a pilot plant installed in a municipal wastewater-treatment plant. Sampleswere adsorbed usingsilica C18 cartridges and the concentrates were tested for mutagenicity in the Salmonellatyphimurium reversion test with strains TA98 and TA100. Non-concentrated water samples were tested with two plantgenotoxicity assays (the Allium cepa root anaphase aberration test and the Tradescantia/micronucleus test).Mutagenicity assays in bacteria and in Tradescantia showed borderline mutagenicity in some of the wastewatersamples, independent of the disinfection procedure applied. Negative results were obtained in the A. cepa anaphaseaberration test. These results indicate that, in the conditions applied, wastewater disinfection with PAA and NaClOdoes not lead to the formation of significant amounts of genotoxic by-products.