Reflexos das atividades antropogênicas: genotoxicidade em peixes no médio Rio Aquidauana, Pantanal Sul

Abstract

The Pantanal is the biome with one of the largest wetlands in the world, with great biodiversity, being annually flooded by the Upper Paraguay River Basin, where the Aquidauana River is one of its main tributaries. The Aquidauana River has the function of supplying several municipalities, an economic and tourist source, however, it undergoes disturbances from human activities, such as excessive fishing, riverside pollution and agro-industrial activities. The aim of the study was to evaluate the water quality of the Aquidauana River through physicochemical parameters and to identify possible genotoxic damage in Pantanal fish species. Therefore, the research was conducted in the middle course of the Aquidauana River at six sampling points. With a multiparameter probe, the physicochemical parameters were measured. The fish were collected with waiting nets, their length and weight measured. The species Hypostomus regani, Prochilodus lineatus, Brycon hilarii and Mylossoma duriventre were sampled and identified. For the genotoxicity assay, blood smears were prepared and nuclear changes were counted under an optical microscope. The physicochemical parameters measured were within the standards allowed by CONAMA legislation 357/2005, or there is no maximum value. The physicochemical parameters are important to identify the first water quality status. In relation to length, weight and feeding habits, B. hilarii had the highest weight and length, followed by the species H. regani, P. lineatus and M. duriventre. Regarding feeding habits, H. regani and P. lineatus are detritivores and B. hilarii and M. duriventre are omnivores. Nuclear alterations were identified as nuclear invagination, nuclear budding, lobulated nucleus and binucleate cell, where fishes of the species H. regani presented higher proportions of significant nuclear alterations. The feeding habit of H. regani favors contamination, as it feeds on material decanted from the bottom of the river. Species with detritivorous habits showed a higher proportion of genotoxicity in relation to omnivorous eating habits. In short, the assessment of the water quality of the Aquidauana River through physical-chemical parameters proved to be in compliance with current legislation. However, only physicochemical analyzes do not prove the quality of the Aquidauana River, requiring further tests. Thus, it was possible to verify that the Aquidauana River has been undergoing environmental disturbances arising from human activities, which may not only affect the organisms that live in the river, but also the populations that consume this water daily.