Evaluation of the genotoxicity of nufosate in Tambaki (Colossoma macropomum) under chronic exposure

Abstract

Herbicides are widely used chemical products; however, they can cause environmental contamination. The aim of this study was to assess the acute toxicity of nufosate and to analyze chromosomal aberrations in fish exposed to the herbicide. The assessment of acute and chronic toxicity was carried out on Colossoma macropomum. For acute toxicity, the CL50-48h test was used, while chronic toxicity was assessed during 30 days of exposure. Genotoxic effects were observed, including nuclear alterations in fish cells. The methodology included laboratory and statistical analyses to interpret the results. The results indicated that the lethal concentration of nufosate for tambaqui was 14.32 mg/L. In different water depth scenarios, nufosate exhibits a medium risk at a concentration of 0.96 mg/L, corresponding to 100% of the product's recommended dosage, and a low risk in concentration ranges varying from 0.48 to 0.015 mg/L in bodies of water with a depth of 0.3 m and from 0.144 to 0.002245 mg/L in bodies of water with a depth of 2m. After chronic exposure for thirty days at a concentration of 4.77 mg/L, the Mann-Whitney test found a significant difference between the fish exposed to nufosate and the control group, suggesting potential nuclear damage caused by the herbicide. This analysis used the micronucleus test to blindly assess nuclear alterations in erythrocytes. This study emphasizes the importance of responsible use of the herbicide nufosate, indicating that although it can cause nuclear alterations, it does not generate a specific pattern of nuclear changes in fish.

Keywords: genetic degeneration; ecotoxicology; herbicide; environmental poisoning; micronucleus; monitoring.