Biomarcadores genéticos em peixes detritívoros do Rio Iguaçu

Abstract

Socio-economic development and consequent environmental exploitation and degradation have exerted strong pressure on aquatic environments. The Iguaçu River, the largest in the state of Paraná, is directly affected by the intensification of resource exploitation. Activities such as agriculture, industry and the construction of dams pose threats to ecological maintenance and biodiversity. The Iguaçu River is also characterized by high endemism, yet it has already been classified as the second most polluted river in Brazil. The aim of this study was to analyze the toxicity of water from the Iguaçu River basin using genetic markers in two genera of detritivorous fish used as bioindicators: Ancistrus and Corydoras. Collections took place in the winter of 2022 using electric fishing, at ten different points, one of which was the Iguaçu National Park (preserved point) and urban, rural and larger riparian forest points in the cities of Dois Vizinhos, Cascavel and Curitiba, in the state of Paraná - Brazil. The biomarkers used were: the micronucleus rate (MN) and erythrocyte nuclear alterations (ENAs) and the comet assay protocol for liver, kidney and blood. For the comet assay, species of the Ancistrus genus showed no statistically significant differences, while organisms of the Corydoras genus showed a higher rate of damage in the rural area of Curitiba for kidney and liver. As for the micronucleus biomarker and erythrocyte nuclear alterations, the species of the Ancistrus genus showed significant alterations in relation to bubble-type ANS, with a higher frequency of abnormalities in the urban area of Dois Vizinhos. With regard to the genus Corydoras, there were alterations to the lobed-type ANS, which differed between the urban and preserved sites in the city of Curitiba. This study highlights the importance of using different bioindicators for biomonitoring water bodies such as the Iguaçu River, which is widely used for public supply and is also of great ecological importance.