Sublethal effects of atrazine concentrations exposure on tadpoles of Dendropsophus minutus: evaluation of redox status, micronuclei frequencies and comet assay as biomarkers

Abstract

Atrazine (ATZ) is an herbicide that can persist in terrestrial and aquatic environments and potentially cause significant harm to amphibian health. Therefore, the Brazilian National Environment Council (CONAMA) sets the limit concentration of ATZ in waters at 2μg/L. Our study evaluated the genotoxic, mutagenic, and biochemical alterations in Dendropsophus minutus tadpoles in the 25 Gosner stage, to acute exposure (96h) of ATZ (T1 - 0.02µg/L, T2 - 0.04µg/L, T3 - 0.08µg/L, T4 - 2µg/L). The comet assay showed all concentrations caused DNA damage with an increase to T2, T3, and T4. In the micronucleus test (MN) and Erythrocyte Nuclear Abnormality test (ENA), T3 and T4 accumulated more anucleated (AN), binucleated cells (BC) and ENAs. Redox imbalance was not detected. Therefore, we conclude that the concentrations tested are not safe for the health and development of D. minutus tadpoles, and the CONAMA limit needs to be reviewed since all tadpoles presented DNA damage. More studies are necessary to identify other alterations that ATZ can cause in the tadpole health of tropical species. Therefore, implementing public policies aimed at safeguarding the lives of both adult and juvenile amphibians is imperative for the conservation of biodiversity and ecosystem stability.