Study of the effect of residues of pharmaceuticals on the environment on the example of bioassay Microtox®

Abstract

Residues of pharmaceuticals present in the aqueous environment can be found in a mixture of different substances wherein drugs not remain inert with respect to each other. In such mixtures, a phenomenon of synergism or antagonism may occur, which can contribute to increase or decrease the overall toxicity of the mixture of drugs. Pharmaceuticals, namely, diclofenac (sodium salt), oxyteracycline hydrochloride, fluoxetine hydrochloride, chloramphenicol, progesterone, estrone, androstendione, ketoprofen, and gemfibrozil, were mixed with each other at different ratios of EC50 (effective concentration) and tested using MICROTOX®. Attempt was also made to determine whether a pH change of the sample containing pharmaceuticals affects the total toxicity of the sample. The most toxic mixtures of selected pharmaceuticals proved to be those containing diclofenac and chloramphenicol, reaching up to 90 % of the toxicity against the test organism. Based on results obtained, it can be concluded that the change of pH has a significant effect on the toxicity of androstenedione, gemfibrozil, oxytetracycline hydrochloride, diclofenac, and progesterone.