Toxicity of the insecticide chlorpyrifos to the South American toad Rhinella arenarum at larval developmental stage

LIENDRO, MARTA NATACHA; FERRARI, ANA; MARDIROSIAN, MARIANA; LASCANO, CECILIA; VENTURINO, ANDRÉS

ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015

1382-6689

Chlorpyrifos (CPF) is an insecticide widely used for pest control in the fruit-productive regionof North Patagonia, Argentina, where it is found in superficial waters. The aim of this studywas to establish the toxic effects of CPF in Rhinella arenarum toad larvae as a potentiallyexposed species. We determined the 96 h-LC50 (1.46 ± 0.27 mg/L), the LOEC (0.81 mg/L, LC10)and NOEC (0.43 mg/L, LC1) for CPF lethality as endpoint. We also analyzed biochemicalbiomarkers in larvae exposed to sublethal CPF concentrations. The IC50 for cholinesterasewas 0.113 ± 0.026 mg/L, one order of magnitude lower than the LC50. Carboxylesterase activ-ity was inhibited, buffering OP toxicity on cholinesterase. Reduced glutathione increasedafter 24 h as an antioxidant response, and decreased at 96 h together with catalase activity,due to oxidative stress. These biochemical effects suggest that environmentally relevantCPF concentrations pose a threat to R. arenarum larvae progression.