Peixes como bioindicadores de qualidade da água do Rio São Francisco Falso Braço Sul e Braço Norte, Paraná, Brasil

Abstract

The history of aquatic pollution goes back a long way. We know that this pollution has harmed our rivers, lakes and waterways, and has a negative effect on the biota. Different pollutants can come from different sources, like domestic sewage, and spread through productive activities such as the exploitation of renewable and non-renewable resources. Agricultural by-products such as pesticides, herbicides and fertilizers, and industrial waste emissions are the activities that most contaminate the environment. With inefficient effluent treatment systems, these pollutants end up falling into waterways, compromising the life present in these environments. This study was carried out with the aim of investigating whether these contaminants have reached our rivers and caused negative impacts on the local fauna. Fish specimens of the genus Hypostomus (Hypostomus aff. tietensis and Hypostomus ancistroides) were collected, which were taken to the laboratory, euthanized, and had blood collected by cardiac puncture. Two blood smear slides were made from each individual, which were then fixed and stained, and subsequently analyzed under an optical microscope at 1000x magnification. These analyses revealed changes in the red blood cells of both species, indicating possible contamination with genotoxic effects. Significant differences were also observed in the number of morphological changes when comparing the animals captured between the sampling points of the São Francisco Falso River South Arm x North Arm. These differences indicate that there are possible differences in the levels of contamination between the points, but further studies are needed to confirm this hypothesis.