TOXICITY OF BINARY-MIXTURES OF ORGANIC-CHEMICALS

Toxicity of binary mixtures of organic chemicals was evaluated using the Microtox test, in order to derive a more realistic approach for predicting mixture toxicity. Both additive and less than additive effects were found from binary mixtures of nonreactive toxicants. Concentration addition can be expected between two nonreactive chemicals, provided that the requirement of parallel dose-response curves is fulfilled. The study also identified the conditions for a complex-type joint action to take place. Finally, experimental isobolograms were analyzed based on a bivariate toxicity model to provide a rational estimation of model parameters. The isobolograms and the additive indices generated by this study can be used to predict the combined toxic effects from various organic mixtures. (C) 1995 by John Wiley and Sons, Inc.