The effect of various nucleophiles on the mutagenicity of softwood kraft chlorination effluent

The mutagenicity of softwood kraft chlorination effluent in the Ames Salmonella assay was measured in the presence of various added nucleophiles. The relative effectiveness of the applied nucleophiles in reducing the mutagenicity of the effluent was in the order of OH − > SO 2 (HSO 3 −, SO 3 =)>glutathione>pyrrolidine>S 2O 3, which appeared to follow in order of decreasing nucleophile basicity. Both the carbonyl group and organically bound chlorine contents of the effluent decreased upon addition of nucleophiles. In all cases, carbonyl loss appeared to be the more important factor in controlling mutagencity reduction. The conclusion can be drawn that deactivation of kraft chlorination effluent, and possibly the chlorination products of other types of naturally occurring organic material (e.g., humic acid), may be achieved by treatment with any appropriate nucleophile. Effective nucleophiles can include substances such as glutathione, which is endogenous to all mammals, and as such may represent the biochemical basis for a detoxication mechanism.