Efeitos tóxicos de clotianidina para espécies alternativas de colêmbolos em solos tropicais

Abstract

Pesticides are used in agriculture in order to protect crops and allow productivity gains, for which various commercial formulations are used. Clothianidin is an active ingredient (a.i.) of the neonicotinoid class that is present in commercial formulations of insecticides for the chemical treatment of seeds in Brazil. Currently, studies have shown concern about the effects of this a.i. in the environment to non-target soil organisms such as springtails. These studies have been carried out with standard species and artificial soil, and little is known about the effects of a.i. on tropical soils. This study evaluated the effects of clothianidin on alternative springtail species (Proisotoma minuta and Sinella curviseta) in tropical natural soils (Oxisol and Entisol) through chronic toxicity tests. It was also estimated the ecological risk for the species in soils contaminated by the i.a. Chronic toxicity essays were based on ISO 11267 (2014). Effects on the reproduction of both species were observed, regardless of the type of soil tested, although the species sensitivity to the a.i. was similar when compared to the same soil type. Higher toxicity for both species was observed in Entisol, where EC50 values ranged from 0.077 to 0.081 mg kg-1 between species, while in Oxisol, EC50 values ranged from 0.421 to 0.495 mg kg-1 between species. The ecological risk evaluated for the two species indicated the risk is accentuated for both species in Entisol contaminated by the a.i., although P. minuta seems to be the species with the highest probability of toxic effect.