Mutagenicity, hepatotoxicity, and neurotoxicity of glyphosate and fipronil commercial formulations in Amazon turtles neonates (Podocnemis expansa)

Pesticides are considered one of the main causes of the population decline of reptiles worldwide, with freshwater turtles being particularly susceptible to aquatic contamination. In this context, we investigated the potential mutagenic, hepatotoxic, and neurotoxic effects in neonates of Podocnemis expansa exposed to substrate contaminated with different concentrations of glyphosate and/or fipronil during embryonic development. Eggs collected from the natural environment were artificially incubated in sand moistened with pure water, water added with glyphosate Atar 48 & REG; at concentrations of 65 and 6500 & mu;g/L (groups G1 and G2, respectively), water added with fipronil Regent & REG; 800WG at 4 and 400 & mu;g/L (groups F1 and F2, respectively) and, water added with the combination of 65 & mu;g/L glyphosate and 4 & mu;g/L fipronil or with 6500 & mu;g/L glyphosate and 400 & mu;g/L fipronil (groups GF1 and GF2, respectively). For mutagenicity analysis, we evaluated the frequency of micronuclei (MN) and other erythrocyte nuclear abnormalities (ENAs), while for evaluation of hepatotoxicity and neurotoxicity, livers and encephalon were analyzed for histopathological alterations. Exposure to pesticides, alone or in combination, increased the frequency of erythrocyte nuclear abnormalities, particularly blebbed nuclei, moved nuclei, and notched nuclei. Individuals exposed to fipronil exhibited congestion and inflammatory infiltrate in their liver tissue, while, in the encephalon, congestion, and necrosis were present. Our study confirms that the incubation of eggs in substrate polluted with glyphosate and fipronil causes histopathological damage and mutagenic alteration in P. expansa, highlighting the importance of using different biomarkers to evaluate the ecotoxicological effects of these pesticides, especially in oviparous animals.

Automated summary

Pesticides, especially glyphosate and fipronil, have mutagenic and toxic effects on neonates of Podocnemis expansa, causing histopathological damage and genetic alterations. The presence of blebbed nuclei, moved nuclei, and notched nuclei indicate the increased frequency of erythrocyte nuclear abnormalities. Exposure to fipronil leads to congestion and inflammatory infiltrate in the liver tissue and congestion and necrosis in the encephalon. This study highlights the significance of using different biomarkers to evaluate the ecotoxicological effects of pesticides on oviparous animals.