Evaluation of genotoxic potential of the middle section of the Danube River and its major tributaries

Abstract

The middle section of the Danube River basin in the previous three Joint Danube Surveys (JDS) was found to be under intensive pollution, mainly affected by wastewaters. As a consequence of the lack of wastewater treatment plants, complex xenobiotics mixtures may get into surface water and decrease water quality and organisms’ health. Some xenobiotics may induce different types of DNA damage. Hence, DNA damage could be a useful biomarker in the detection of “early warning signals” of organisms’ exposure to genotoxic compounds, while the usage of bioassays batteries can provide better insight into a genotoxic potential. This study was conducted in 2019, during the JDS4 expedition, to assess the genotoxic potential of nine sites on the section of the Danube River which goes through Serbia and its major tributaries: the Sava, Tisza and Velika Morava. Blood and muscle of Alburnus alburnus (bleak) were used for genotoxicity assessment by comet, micronucleus and RAPD assays. In comet assay, the highest level of DNA damage was recorded at the Velika Morava mouth (JDS 39) and on the Danube River, downstream Radujevac (JDS 41). The highest frequency of micronucleus was recorded at the Sava mouth (JDS 36) and on the Danube River, downstream Pančevo (JDS 37). The lowest level of DNA damage in both tests was recorded on the Sava, site Jamena (JDS 35). The RAPD analysis distinct three major groups: Tisza mouth (JDS 33) and sites on the Sava (JDS 35, JDS 36), then two sites on the Danube River (JDS 37, JDS 41) and one site on the Danube River, Ram (JDS 40) with the Velika Morava mouth (JDS 39). Analyzed bioassays showed different sensitivity where the comet assay had the highest potential in discrimination of sites based on genotoxicity. Bleak was proved to be a reliable bioindicator in eco/ genotoxicological studies.