Toxicity of Glyphosate on Physalaemus albonotatus (Steindachner, 1864) from Western Brazil

Abstract

Amphibian declines have been reported worldwide and pesticides can negatively impact this taxonomic group. Brazil is the world’s largest consumer of pesticides, and Mato Grosso is the leader in pesticide consumption among Brazilian states. However, the effects of these chemicals on the biota are still poorly explored. The main goals of this study were to determine the acute toxicity (CL50) of the herbicide glyphosate on Physalaemus albonotatus, and to assess survivorship rates when tadpoles are kept under sub-lethal concentrations. Three egg masses of P. albonotatus were collected in Cuiabá, Mato Grosso, Brazil. Tadpoles were exposed for 96 h to varying concentrations of glyphosate to determine the CL50 and survivorship. The CL50 was 5.38 mg L-1 and there were statistically significant differences in mortality rates and the number of days that P. albonotatus tadpoles survived when exposed in different sub-lethal concentrations of glyphosate. Different sensibilities among amphibian species may be related with their historical contact with pesticides and/or specific tolerances. Further studies are required to determine the degree to which this taxonomic group is threatened by chemical contaminants.