Influence of environmental quality on the genotoxic potential of fish from streams of the upper Paraná River

Abstract

The objective of this research was to evaluate the influence of soil cover and use and water quality in streams in the Upper Paraná River basin on the genotoxic potential in two native fish species – Pimelodella avanhandavae and Hypostomus ancistroides. Land use and land cover in the streams analyzed is primarily associated with anthropogenic activities, especially agricultural. The physical-chemical parameters of the water were within the limits established by the Brazilian environmental resolution, with the exception of electrical conductivity, which exceeded the maximum allowed values. We did not find significant differences (p>0.05) between the sites regarding the frequency of micronuclei in both species. For other abnormalities, however, significant differences were observed between the compared sites for P. avanhandavae, with a higher frequency of cytoplasmic invagination in the Curral de Arame stream, which showed higher conductivity and lower dissolved oxygen concentration than the Laranja Doce stream.For H. ancistroides, both lobulated nucleus and nuclear invagination were more frequent in the Curral de Arame stream, characterized by greater agricultural occupation than the Água Boa stream, which is located in an urban area. In this sense, the frequencies of the aforementioned abnormalities indicate that, possibly, the impact of agriculture is being more harmful to species than the impacts resulting from urban occupation.