Genotoxicity of the Herbicide Picloram (TORDON ® 24K) on tadpoles of Boana pulchella (Amphibia, Anura, Hylidae)

Resumen

Picloram (PIC) is an herbicide widely used in Uruguay to control weeds, especially in forest crops. In the present study, we evaluate the acute toxicity and genotoxicity of formulated 24.9% PIC-based Tordon®24K on Boana pulchella tadpoles under standard laboratory conditions. In the acute toxicity test we use mortality as the endpoint and we obtained a 48-h LC50 of 16.5 mg/L, LOEC 14.5 mg/L, and NOEC 12.5 mg/L. We determined genotoxicity in GS36 tadpoles exposed to sublethal concentrations of 8.5 (NOEC/1.5) and 12.5 mg/L (NOEC) PIC using micronucleus frequency (MN) and occurrence of nuclear abnormalities (AN) as endpoints. We noticed a significant increase in the frequency of MN and AN in all treatments tested at sublethal concentrations. Our findings demonstrate the genotoxic effects of this herbicide, which represent a danger to amphibians that inhabit agroecosystems. Based on the results obtained and considering that Boana pulchella is not a threatened species and has a wide distribution in the Uruguayan territory and the Pampa Biome, it could be considered a reference organism in environmental monitoring programs in the region.