Acute Toxicity and Impact on Anuran Metamorphosis of EnvironmentallyRelevant Concentrations of Neonicotinoid and Anthranilic Diamide Insecticides

FONSECA PEÑA, SHIRLEY VIVIAN DANIELA; BRODEUR, JULIE CÉLINE; NATALE, GUILLERMO SEBASTIÁN

Montevideo

Congreso; SETAC Latin America 15 th Biennial Meeting; 2023

Society of Environmental Toxicology and Chemistry

In the agricultural region of the Argentine Pampa, the neonicotinoid (NEO) and anthranilic diamides (AD) families of insecticides are widely used on numerous crops, including soybean and corn. Both families of insecticides are persistent in the environment and can reach the aquatic environment by lixiviation and runoff. The objective of the present study was to analyze the impacts on amphibian species native to the Pampa region of the commercial formulations Actara and Confidor containing the NEOs, thiamethoxam (THIA) and imidacloprid (IMI), and the commercial formulations Coragen and Fortenza containing the ADs, chlorantraniliprole (CHLO) and cyantraniliprole (CYAN). Acute and chronic toxicity as well as impacts on development were examined in tadpoles of the toads Rhinella arenarum, Rhinella fernandezae and the frog Scinax granulatus at a range of concentrations. The lethal concentration 50 (LC50) values obtained after 96h of exposure were greater than 10 mg/L in all cases, the greatest toxicity being observed in the case of Scinax granulatus exposed to IMI, with a 96h LC50 of 11,28 mg/L. With regards to metamorphosis, the effects occurrred mainly between stage 39 and 42. In general, NEO and AD acted differently at environmentally-relevant concentrations. In the case of NEO, exposure to THIA caused a delay in the time to metamorphosis of R. arenarum starting from the lowest concentration tested (5 µg/L), while the percentage of animals completing metamorphosis was not affected. For its part, exposure to IMI had no major effects on the development. Exposure to AD, CHLO and CYAN, altered the time to metamorphosis in a non-monotonic manner (increased or decreased depending on the concentration) and significantly reduced the percentage of animals completing metamorphosis but, in this case, with linear dose-response relationship.