Toxicity of individual pharmaceuticals and their mixtures to Aliivibrio fischeri: Experimental results for single compounds, considerations of their mechanisms of action and potential acute effects on aquatic organisms

In the first part of a broader study on the effects of individual and multicomponent mixtures of pharmaceutical active compounds (PhACs), the authors use the Microtox® test system to analyse in detail the effects of ten widely used human and veterinary PhACs towards the bioluminescent bacterium Aliivibrio fischeri. The experimental results indicated moderate toxicity for the majority of the tested compounds. The comparison between our experimental IC50 and those predicted from the Quantitative Structure-Activity Relationship (QSAR) models indicated that most of the tested PhACs behave as polar narcotic compounds towards A. fischeri (only the antibiotic chlortetracycline seemed to have a specific mechanism of action). A comparison between our experimental results and a collection of acute toxicity data on other non-target organisms indicated that in general A. fischeri has a comparable sensitivity to other aquatic species. However, according to the Globally Harmonised System of Classification and Labelling of Chemicals (GHS), the majority of the investigated chemicals can be classified as harmful or non-toxic chemicals for aquatic ecosystems. Finally, based on the comparisons among the 95(th) percentile of Measured Environmental Concentrations (MECs) found in EU water bodies and acute toxicity data on various aquatic organisms, no risk to aquatic life exists when the tested PhACs are assessed as individual chemicals.

Authors: Di Nica V, Villa S, Finizio A. ;Full Source: Environmental Toxicology & Chemistry. 2016 Jul 28. doi: 10.1002/etc.3568. [Epub ahead of print] ;