Predicting the Degree of Toxicity of Effluent from Reactive Dye Mixtures

Environmental and public health issues associated with dyes and their effluents are problematic areas for any dyehouse. If the toxicity and color of dyeing effluent can be predicted quantitatively before dyeing, one can select suitable dyes to reduce envi ronmental pollution. This study examines the acute toxicity of dyes and associated auxiliaries in terms of EC50, and these data are used to predict the toxicity of the dyeing effluent. The prediction accuracy is satisfactory when some statistical ap proaches, such as linear and nonlinear regression, are used. Furthermore, in order to make the toxicity data much easier to understand and much more directly comparable with each other, a toxicity index has been created according to the EC50values in this study. Incorporating the toxicity information of the dyes with a computer color matching system permits the prediction of effluent toxicity generated by colorant recipes. This should assist colorists to select a “greener” formula while satisfying basic color quality requirements and will let colorists know well ahead of time the impact of toxicity from the effluent on the environment.