Ecotoxicological study of fluoroquinolone antibiotics mixture on algae

Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Botany and Ecology Candidate: Mgr. Lucie Kozlová Supervisor: RNDr. Jitka Vytlačilová, Ph.D. Title of rigorous thesis: Ecotoxicological study of fluoroquinolone antibiotics mixture on algae This thesis is focused on ecotoxicological risk assessment of two fluoroquinolone antibiotics - ciprofloxacin and norfloxacin. A growing test with algae Desmodesmus subspicatus was performed based on the OECD Guidelines n. 201 for testing of chemical substances on freshwater algae and cyanobacteria. The aim of this test was to determine the influence of individual substances and their mixtures in various ratios (1:1, 1:2 and 2:1) on green algae. The test was ended by EC50 evaluation after 72 hours. Only some of the mixture appeared to be more toxic than a single substance. Theoretical calculation of mixtures toxicity has been performed and compared with the experimentally obtained data. All EC50 values obtained significantly exceed the concentration of substances in the environment reported in the literature. Keywords: ecotoxicology, ciprofloxacin, norfloxacin, Desmodesmus subspicatus, mixture