Genetic damage induced by water pollutants in the freshwater fish Hyphessobrycon luetkenii (Characidae) in a reservoir of the Canela National Forest, Brazil

Fish have been shown to act as sentinel organisms in genetic toxicology studies and the micronucleus (MN) test using fish erythrocytes has been successfully used to evaluate the genotoxic impact of environmental pollutants on aquatic environments. This study used the MN test of peripheral blood of specimens of a native fish species (Hyphessobrycon luetkenii) to evaluate the genotoxicity of the water of two unconnected reservoirs of the Canela National Forest in southern Brazil. Fish were caught in the reservoirs and MN frequencies in blood smears were determined. Baseline MN frequency of H. luetkenii was determined in the uncontaminated reservoir (reference site) and compared with the results obtained at two different sampling periods (winter and spring) in the reservoir which receives discharges of industrial and municipal wastes. In the spring season, MN frequency in the contaminated reservoir was about five times higher than in the reference site (0.51‰ and 0.10‰, respectively). The results of this study indicate that some fish populations are at risk of exposure to genotoxic pollutants in the Canela National Forest.