Toxic and genotoxic activity of river waters of the Kazakhstan

Introduction In this study, physicochemical, genotoxic, and mutagenic properties of water samples from 10 rivers of the Almaty region (Kazakhstan) were evaluated. Results The results of the study demonstrated an increased level of mineralization and electrical conductivity that might be caused by the high concentration of dissolved mineral salts and ions such as Na+, K+, Ca2 +, Cl−, SO42−, HCO3−. The excess of Maximum Allowable Concentrations (MACs) for various heavy metals was revealed. The results of tests using the pXen7-lux biosensor showed toxic effects of river waters. At the same time, the studies involved lux biosensors pRecA-lux, pColD-lux, pSoxS-lux, pKatG-lux did not find any genotoxic and oxidative effects. However, toxicity and mutagenicity of the studied water samples was detected by using plant test (Allium cepa and Hordeum vulgare). Phytotoxic, cytotoxic (decrease in the mitotic index) and mutagenic (increase in the frequency of chromosomal aberrations) activity of the water samples was observed. The data of in vivo tests (Danio rerio) showed the high toxicity and teratogenicity of river waters for fish embryos at all stages of development. Conclusions The results of this comprehensive study indicate that the contamination of the surface natural waters poses a threat to rivers dwellers and the human population in the rivers areas.