Studies of Acute and Chronic Toxicity of Commercial Herbicides with Glyphosate against Danio rerio

Abstract

Glyphosate or N-(phosphonomethyl) glycine is a broad spectrum non-selective systemic herbicide, used to kill weeds, mainly in soybean crops. Nowadays there are many controversies about the intensive use of these herbicides due to the potential environmental impact and the effects on human health. The environmental impacts of commercial Glyphosate formulation Roundup were assessed by evaluation of acute and chronic toxicity of Danio rerio fish. The effects of glyphosate commercial formulations and glyphosate isopropylamine salt solutions were evaluated in different steps. First the lethal doses of Roundup herbicide toward the experimental models were determined. Subsequently the specie was exposed to sublethal concentrations of both, the commercial preparations and pure glyphosate salt in order to evaluate the chronic toxicity. Acute toxicity was assessed by calculating the mortality indexes and chronic toxicity by measuring several biochemical parameters such as the activity of marker enzymes like aspartate aminotransferase (AST), alanine aminotransferase (ALT) and acetylcholinesterase (AchE). The registers of histological alterations in liver tissue sections were also considered in this study. Commercial herbicides produce mortality of D. rerio and sublethal doses of these herbicides and the salt of the pure compound produce effects of chronic toxicity at the liver and muscle level; such are enough causes to limit the potential survival of these organisms in the medium.