ESTRÉS OXIDATIVO Y GENOTOXICIDAD EN LARVAS DE RHINELLA ARENARUM EXPUESTAS AL INSECTICIDA DIMETOATO

ACQUARONI, MERCEDES; PELUSO JULIETA; SVARTZ GABRIELA; ARONZON, CAROLINA M; PÉREZ COLL CRISTINA S

Congreso; XXXVII CONGRESO INTERAMERICANO VIRTUAL DE INGENIERÍA SANITARIA Y AMBIENTAL; 2021

There is a great concern worldwide about the global decline of amphibians particularly by agrochemical pollution. The aim of this study was to assess oxidative stress and genotoxicity of a commercial formulation of the insecticide dimethoate in Rhinella arenarum larvae, using sublethal biomarkers. The 24 h and 96 h-LC50 values of dimethoate to R. arenarum were 48.81 and 38.86 mg L-1 while the 96 h-No Observed Effect Concentration (NOEC) value was 20 mg L-1. For sublethal biomarker assays, R. arenarum larvae were exposed to 1.25, 2.5 and 5 % of the NOEC-96 h (0.25, 0.5, 1 mg L-1 dimethoate respectively). After 96 h of exposure, inhibition of catalase (CAT) and glutathione S-transferase (GST) activities were registered. Also, an increased superoxide dismutase (SOD) activity was observed in larvae exposed to the highest concentration (1 mg L-1). Lipid peroxidation by increased TBARS levels in larvae exposed to 0.5 and 1 mg L-1 was detected. No differences in micronuclei frequency between treatments and negative control were observed. These results demonstrate the oxidative toxicity of dimethoate at sublethal concentrations in Rhinella arenarum larvae. The disruption of defense mechanisms may contribute to a deleterious impact on amphibian populations from habitats exposed to this organophosphorus insecticide.