Single and mixture toxicity of four pharmaceuticals of environmental concern to aquatic organisms, including a behavioral assessment.

Pharmaceuticals are frequently detected in aquatic environments as mixtures and can cause toxic effects to non-target organisms. We aimed to evaluate the single and mixture effects of the pharmaceuticals metformin, bisoprolol, ranitidine and sotalol using Daphnia similis and Danio rerio. In addition, we aimed to test the predictive accuracy of the mathematical models concentration addition and independent action and to evaluate the nature of the possible toxicological interactions among these pharmaceuticals using the combination index-isobologram model.