Toxicity of glyphosate upon the freshwater prawn Palaemonetes argentinus.

Abstract

Glyphosate (Roundup®) is one of the most commonly used herbicides in agricultural systems in the world that control a broad-spectrum of worst weeds to cheap. The present study examine, under laboratory conditions, the acute effect, oxygen consumption, ammonia-N excretion and individual growth of Palaemonetes argentinus under the influence of the Roundup® commercial formulation. The experiments were conducted at 25 ± 2 ºC. Juveniles prawns were exposed to different solutions of glyphosate. Measurements of dissolved oxygen were taken at the beginning of the experiment and at each hour during the first 4 h and 24 h. Ammonia-N was determined at the beginning and the end of the experiment (24 h). LC50-96 was 0.1418 ml.L-1 of glyphosate Roundup®. Mortality rate for 72 h in maximum solution was 100%. Oxygen uptake and ammonia-N excretion of prawns exposed to concentrations was different than in controls animals. In glyphosate treatments, oxygen consumption and ammonia-N excretion decreased. This variation could be showed in the metabolic requirement of oxygen consumption and the amino acids degradation. The physiologic effects suggests that this prawns to be sensible to Roundup®. In general, the growth was similar among control and treatment prawns but high mortality in the experiments with herbicide solutions was observed. This action could be effected by Roundup® herbicide on regulatory mechanisms of molt process in the prawn growth.