Environment

human alterations in rivers and urban effluents can promote ecotoxicological effects on ichthyofauna and public health, a case study

Abstract

Rivers are integrated aquatic systems that are subject to abiotic and biotic actions. When a river is altered, it changes the natural flow of nutrients and sediments. In addition, the use of organophosphates in monocultures near streams and rivers can result in their contamination. Physical alterations in the river bed, added to contamination through substances with mutagenic potential, can generate deleterious and cumulative effects on organisms in aquatic ecosystems. Therefore, the study of monitoring aquatic ecosystems is necessary and pertinent. Therefore, the present study aimed to evaluate the possible ecotoxicological effects on Astyanax bifasciatus, an endemic fish species from southern Brazil. The fish were collected at points with different degrees of anthropic activity in the middle Iguaçu basin (SC). We used the methodology of analysis of nuclear alterations (micronucleus), and activity of the acetylcholinesterase enzyme (AChE). The results of our work pointed out that in the three sampling sites, fish exhibited micronuclear abnormalities. The tests of acetylcholinesterase enzyme activity showed differences in its activity when compared between the groups collected in different sampling sites, Rio Timbó-SC and Rio Pintado-SC. Our results reinforce the hypothesis that water systems receiving untreated urban effluents, combined with possible xenobiont agents from nearby monocultures and environmental changes, can lead to cellular alterations at the nuclear/enzymatic level. Therefore, the constant monitoring of aquatic ecosystems is increasingly pertinent, given the contemporary challenges in maintaining a balance between human activity and the preservation of natural resources.

Keywords: Astyanax bifasciatus; micronucleus; acetylcholinesterase; alterations.