DNA damage exerted by mixtures of commercial formulations of glyphosate and imazethapyr herbicides in Rhinella arenarum (Anura, Bufonidae) tadpoles

• Published in: Ecotoxicology (London) 2019-04, Vol.28 (3), p.367-377
• Main Authors: Carvalho, Wanessa F., Ruiz de Arcaute, Celeste, Pérez-Iglesias, Juan Manuel, Laborde, Milagros R. R., Soloneski, Sonia, Larramendy, Marcelo L.
• Format: Article
• Language: English
• Subjects: Acute toxicity; Agricultural management; Agrochemicals; Amphibians; Amphibiotic species; Analysis; Analytical methods; Animals; Bio-assays; Bioassays; Blood cells; Bufonidae; Chromosome aberrations; Damage; Deoxyribonucleic acid; DNA; DNA damage; DNA Damage - drug effects; Earth and Environmental Science; Ecology; Ecotoxicology; Electrophoresis; Environment; Environmental Management; Exposure; Formulations; Gel electrophoresis; Gels; Glycine - analogs & derivatives; Glycine - toxicity; Glyphosate; Health aspects; Herbicides; Herbicides - toxicity; Larva - drug effects; Lethal Dose 50; Lethal effects; Mortality; Mutagenicity Tests; Nicotinic Acids - toxicity; Pesticides; Renewal; Rhinella arenarum; Sublethal effects; Toxicity; Water Pollutants, Chemical - toxicity
• ISSN: 0963-9292; 1573-3017
• DOI: 10.1007/s10646-019-02029-x

Glyphosate (GLY) and imazethapyr (IMZT) are two herbicides commonly used worldwide, either alone or in mixtures. They represent key pesticides in modern agricultural management. The toxicity that results when employed as mixtures has not been characterized so far. Acute toxicity of the 48% GLY-based herbicide (GBH) Credit ® and the 10.59% IMZT-based herbicide (IBH) Pivot ® H alone and their binary combinations was analyzed in Rhinella arenarum tadpoles exposed in a semi-static renewal test. Lethal effects were determined using mortality as the end-point, whereas sublethal effects were determined employing the single-cell gel electrophoresis (SCGE) bioassay. Based on mortality experiments, results revealed LC50 96 h values of 78.18 mg/L GBH and 0.99 mg/L IBH for Credit ® and Pivot ® H, respectively. An increase in the genetic damage index (GDI) was found after exposure to Credit ® or Pivot ® H at 5 and 10% of LC50 96 h values. The combinations of 5% Credit ® -5% Pivot ® H LC50 96 h and 10% Credit ® -10% Pivot ® H LC50 96 h concentrations significantly enhanced the GDI in comparison with tadpoles exposed only to Credit ® or Pivot ® H. Thus, the effect of interaction between GBH and IBH inducing DNA damage in R. arenarum blood cells can be considered to be synergistic.