Abstract

SALVIO, C et al. Toxicidad subletal de clorpirifos sobre Octolasion cyaneum (Annelida: Oligochaeta, Lumbricidae). Agriscientia [online]. 2015, vol.32, n.2, pp.131-138. ISSN 1668-298X.

The aim of this study was to evaluate the survival, biomass, reproductive parameters and morphological changes of Octolasion cyaneum (Annelida: Oligochaeta, Lumbricidae) exposed to different concentrations of chlorpyrifos. The experimental unit consisted of a container with 750 g of soil mixed with the concentration of the insecticide and 10 adult individuals (weight range: 300-600 mg). The treatments were: 0, 120, 240, 480 (recommended application concentration), 960 and 1440 g of chlorpyrifos ha^-1. The design was completely randomized with four replications and was conducted under controlled conditions (20±2ºC, 14L: 10O). O. cyaneum biomass differed between treatments at 7, 14 and 28 days after application (DAA) (p<0.05), and showed the highest biomass in the control. The number of cocoons and juveniles at 56 DAA was higher in the control compared to the other treatments (p<0.05). In the bioassay 235 individuals were alive and 5 were dead, nevertheless the 35% of organisms showed morphological changes. It was noted that the percentage of damage varied depending on the concentration of the insecticide (p = 0.0046). Chlorpyrifos did not affect the survival of O. cyaneum but caused morphological changes and a reduction in biomass and reproductive parameters.

Keywords : Earthworm; Ecotoxicological bioassay; Neurotoxic insecticide.

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