Toxicity of antibiotics mixture to the aquatic biota

Abstract

Nowadays, the occurrence of pharmaceuticals in various concentrations in surface waters and effluents were reported in many papers worldwide. The studies of developed countries showed that many pharmaceutical ingredients can have the negative effect on the growth and reproduction of environmental species. Nevertheless, pharmaceutical pollution has not been considered as environmental issue in Kazakhstan. Previous studies on pharmaceuticals were focused on the effect of single pharmaceutical ingredient exposure to living organisms. Nevertheless, in most cases pharmaceuticals occur in the environment in mixture forms. Therefore, the aim of the following paper was to perform ecotoxicological test for the effect of the mixture antibiotics to the growth of Lemna minor. The combination of five antibiotics as amoxicillin, clarithromycin, azithromycin, sulfamethoxazole and oxytetracycline was used as objects for assessment study. Two measurement variables were used for the evaluation: growth rate and growth inhibition. The results of the experiment showed that the mixture of studied compounds is highly toxic to macrophyte, as the half-maximal effect concentration was below 1 mg/L (0.13 mg/L).