Potential mutagenic effects of the glyphosate herbicide on Gymnotus inaequilabiatus (Valenciennes, 1839)

Larissa Nayara Lima Silva,Claumir Cesar Muniz,Ernandes Oliveira Sobreira Junior,Áurea Regina Alves Ignácio

doi:10.4136/ambi-agua.2730

Larissa Nayara Lima Silva, Claumir Cesar Muniz + Show 2 more

Open Access

https://doi.org/10.4136/ambi-agua.2730

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Abstract

This study analyzed the occurrence of nuclear damage in the red blood cells of Gymnotus inaequilabiatus (Valenciennes, 1839), exposed in vivo to the herbicide glyphosate. The fish were distributed in four groups, namely: control (without addition of herbicide) and contaminated groups with application of 65 µg/L (concentration allowed by CONAMA Resolution), 1 mg/L (maximum limit recommended by the World Health Organization - WHO and Food and Agriculture Organization - FAO) and 5 mg/L (overdose, five times higher than that by WHO and FAO). For the analysis of cell damage, the method of Nuclear Erythrocytic Abnormalities (NEA) was used, containing 1000 cells for duplicate elimination. An increase in cell damage was observed for 144 hours (6-days) of exposure in all controls. Even under a small concentration, there was a clear effect on segmented, renal, lobed formation and mainly on the formation of micronuclei. The high damage was caused in the first 48 hours and reduced after 144 hours, where the fish can have the herbicidal effect blocked. Studies that analyze the mechanisms of action of glyphosate-based herbicides are essential to determine the risks caused by biota, since there is a great divergence on the maximum tolerable limits in water, which affect quality and integrity of these ecosystems.

Highlights

Glyphosate is an organophosphate compound absorbed by the chlorophyll region of plants belonging to the group of “glycine”, its molecule is not perceived as a potential aggressor and may inhibit the synthesis of essential amino acids present only in plants (Galli and Montezuma, 2005)
When comparing treatments according to the time of acute exposure with glyphosate herbicide (Figure 2), we can see that immediately after the exposure of fish to concentrations of 1 mg/L and 5 mg/L with the highest total nuclear damage were found: χ2 (2.3) = 17.58, p = 0.000536 for 48 hours; χ2 (2.3) = 17.58, p = 0.0005362 for 96 hours and χ2 (2.3) = 14.31, p = 0.002512 for 144 hours; p < 0.05 for all comparisons
The mutagenic effects caused by exposure to the herbicide glyphosate can affect the interpretation and transmission of genetic information, which can cause the observed anomalies (Srinivas et al, 2019)

Summary

Introduction

Glyphosate is an organophosphate compound absorbed by the chlorophyll region of plants belonging to the group of “glycine”, its molecule is not perceived as a potential aggressor and may inhibit the synthesis of essential amino acids present only in plants (Galli and Montezuma, 2005). For this reason, this compound can be considered as of lower risk for humans and wild fauna since it basically acts on physiological reactions existing only in plants (Galli and Montezuma, 2005; Mesnage et al, 2015). In the aquatic environment (the main receptor for these substances), the deposition of these contaminants can have short (acute), medium (sub chronic) and long-term (chronic) consequences, which may compromise behavior, growth, development, tissue structure, reproduction or even cause mass lethality in aquatic populations (Rand and Petrocelli, 1985; Bogoni et al, 2014; Mesnage et al, 2015)

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