TOXICITY OF BINARY-MIXTURES OF ORGANIC-CHEMICALS

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