The effect of acute exposure of yellowtail tetra fish Astyanax lacustris (Lütken, 1875) to the glyphosate-based herbicide Templo®.

The herbicide glyphosate (N-(phosphonomethyl)glycine) efficiently eliminates weeds, is frequently present in surface waters, and may damage the health of various non-target organisms. The main objective of this study was to investigate cytotoxic and genotoxic effects in erythrocytes, DNA, and chromosomes of native South American fish Astyanax lacustris exposed to a glyphosate-based commercial herbicide Templo®. The presenty study evaluated the presence of micronuclei (MN), chromosomal aberrations (CA), DNA damage revealed by comet assay, and cellular morphological changes (CMC) as biomarkers. The A. lacustris specimens were exposed to Templo® for 96 h at concentrations below the permitted Brazilian legislation for freshwater environments. The glyphosate-based herbicide caused MN formation, an increased incidence of CA, DNA damage, and several types of CMC in all tested concentrations on A. lacustris. Notably, analyses were significant (p<0.05) for all concentrations, except in the frequency mean of MN at 3.7 µg/L. Thus, considering the intensive use of commercial glyphosate formulations in crops, the herbicide Templo® represents a potential risk of genotoxicity and cytotoxicity for aquatic organisms. Therefore, environmental protection agencies must review regulations for glyphosate-based herbicides in freshwater environments.