ASSESSMENT OF THE TOXICITY OF BENZIMIDAZOLE DERIVATIVES ANDTHEIR EFFECT ON FRESHWATER CERIODAPHNIA DUBIA RICHARD, 1894

Abstract

Recently, due to active development of the pharmaceutical industry, an acute problem of environmental pollution with synthetic biologically active compounds has arisen. Benzimidazole is one of the most common pharmacophores in drugs. Substances containing even trace amount of benzimidazole can have a toxic effect on living systems. Moreover, they are not included in metabolic processes and do not decompose for a long time. Assessing the toxicity of benzimidazole derivatives, its stability in the aquatic environment, and the effect of benzimidazoles on biological parameters will make it possible to predict possible changes in the population dynamiccs of ceriodaphnia and other aquatic organisms.
 The purpose of the study is to assess the toxicity of benzimidazole derivatives and their effect on the survival and fertility of the freshwater Ceriodaphnia dubia Richard, 1894.
 Materials and Methods. Acute and chronic experiments determined standard indicators for toxicological studies: median lethal concentrations (LC50), crustacean lifespan, total number of offspring, number of litters per female, and average hatching time of juveniles. The stability of benzimidazole derivative toxicity was established by the crustacean mortality rate during a 30-day exposure.
 Results. Taking into account the structure of benzimidazole derivatives, the authors evaluated the toxicity of benzimidazole and its seven derivatives to ceriodaphnia over 48 hours based on the median lethal concentration. The highest toxicity was observed for 2-(trifluoromethyl)-5-bromo-1H-benzimidazole (LC50 2.4 mg/l), the lowest – for 2-methyl-1H-benzimidazole (LC50 109.7 mg/l). It was shown that long-term exposure to potassium pyrido[1,2-a]benzimidazole-7-carboxylate (LC50 69.18 mg/l), 38 days of exposure at a concentration of 20 mg/l in a chronic experiment does not lead to a statistically significant change indicators of survival and fertility of ceriodaphnia. The assessment of the stability of potassium pyrido[1,2-a]benzimidazole-7-carboxylate toxicity and the residual toxicity of its breakdown products revealed a relatively low stability of the toxicity of the compound.
 Conclusions. Toxicological assessment of benzimidazole derivatives for aquatic organisms showed the correlation between the toxicity and structural features.