Evaluation of the Sava and the Danube river genotoxicity by Comet assay on different cyprinid fish

Abstract

A number of biological consequences of DNA damage can be initiated at the cellular, organ, whole animal, population and community levels. The comet assay, single cell gel electrophoresis (SCGE), is a sensitive and rapid technique for detection of DNA damage in individual cells based on the migration of denatured DNA during electrophoresis, in which damaged nuclei form comet-like shapes. Since, the large rivers are constantly exposed to variety of chemicals we tested genotoxic potential of rivers Sava and Danube in the Belgrade region, on cyprinid fish. DNA damage was monitored in blood, liver and gill cells of Blicca bjoerkna, Ballerus sapa and Abramis brama by comet assay. The specimens of B. bjoerkna and B. sapa were sampled at the site Duboko (Sava river), which is exposed to untreated municipal wastewater, effluents of the Thermal Power Plant and intensive agricultural activity. The specimens of A. brama were sampled at the site Višnjica (Danube river), which is exposed to untreated municipal wastewater from surrounding Belgrade municipalities. Sampling was performed during February and August 2014. Comet IV Computer Software (Perceptive Instruments, UK) was used for the quantification of DNA damage. The increased level of DNA damage obtained in all tissues of B. bjoerkna and B. sapa (Sava river), and A. brama (Danube river) is in correlation with high chemical pollution detected at Duboko and Višnjica sites. Moreover, this study showed the influence of seasonal variations on the level of DNA damage.