AbstractFourteen series of toxic wastes from various origins (metallurgy, chemical industries, incinerators, industrial treatment plants, etc.) have been studied for their genotoxic properties with theSalmonellareversion assay. To consider realism of environmental impact, a strategy is proposed to assess genotoxicity of the water‐soluble fraction of the wastes. Water‐extractable micropollutants were further concentrated by liquid–liquid extraction or lyophilization prior to genotoxicity testing.None of the 14 crude aqueous fractions was shown to be mutagenic. On the contrary, positive responses were registered on the concentrated phases of two solid wastes derived from one chemical industry and from the treatment of organophosphorus wastewaters. Chemical analysis did not reveal the presence of known mutagens in the positive extracts. Interacting effects between micropollutants is thus hypothesized to explain genotox