Impact of wastewater effluents at two sites at Danube river: genotoxicological assessment.

One of the most severe threats to the Danube River course through Serbia is the direct discharge of untreated wastewater. In biomonitoring studies, faecal indicator bacteria are used to reveal the presence of untreated communal wastewater, while biomarker response in indigenous biota serves as a useful indicator of their harmful potential. The objective of this study was to estimate the genotoxic potential of untreated communal wastewater at two sites on the Danube River, Višnjica (Belgrade) and Novi Banovci, by using in situ approach in white bream (Blicca bjoerkna L.). A comet assay was selected to measure DNA damage in erythrocytes, liver, and gill cells, while the micronucleus test was applied to measure chromosomal aberrations in erythrocytes. Additionally, the accumulation of 22 elements in fish liver and muscle was analysed by ICP-OES meth- od. Simultaneous detection of total coliforms and E.coli in water was performed by enzyme-based Colilert-18 test (IDEXX). Comet assay revealed the highest level of DNA damage in gills at the site Novi Banovci, and in blood at the site Višnjica. The overall frequency of micronucleus at both sites was low. At both localities, the majority of analysed elements showed higher levels in the liver in comparison to muscle. Microbiological indicators confirmed the poor water quality, since at both sites water was categorised as critically to strongly polluted. The results of this study highlighted the importance of in situ biomonitoring approach and the need for more effective management of natural resources and implementation of wastewater treatment systems