Toxicidade de formulações a base de glifosato deve-se parcialmente à presença de surfactante: um estudo em Caenorhabditis elegans

Abstract

Brazil is one of the largest consumers of pesticides in the world, the herbicide glyphosate being the most sold active ingredient in the country in more than 40 commercial formulations. These formulations present in addition to the active principle substances called inert ingredients which are used to improve their chemical and physical properties, increasing their action potential, but which do not have agrochemical activity. Discrimination of these substances is not on labels, making it difficult to assess them. This work aimed to evaluate the toxicity of formulations based on glyphosate Roundup® DI (liquid) (RDI) and Roundup® WG (granules) (RWG), and of urfactants used as adjuvants in formulations of glyphosate, polyoxyethylene amine (POEA) 05 and 15 as well as a mixture of active ingredient + surfactants (MIX) in the body Caenorhabditis elegans in order to establish a cause-effect relationship. The worms (L1) were exposed in liquid medium for 30 minutes at different concentrations of the active ingredient (glyphosate in monoisopropylamine salt), RDI, RWG, POEA 05 or POEA 15. The worms were then transferred to a solid medium where the exposure continued for another 48 hours (chronic exposure). The survival rate, body size, litter size, ROS production and ATP levels were evaluated after 48h. The RWG formulation and POEA 15 showed no toxicity in the evaluated parameters, whereas RDI and POEA 05 increased the mortality rate at concentrations of 0.075 and 0.05%, respectively, causing changes in the development of worms in a concentration dependent manner 0.04 and 0.06% respectively. RDI formulations, POE 05 and 15 surfactants and MIX induced ROS formation. When the animals were exposed to MIX there was no intensification of the toxicity, indicating that RDI toxicity is not due solely to the presence of POEA 05 surfactant. The Roundup® DI formulation and POEA 05 surfactant were more toxic than the active ingredient per indicating that the presence of inert ingredientes increases the toxicity of the formulations and therefore needs to be better studied and better described on pesticide labels.