Toxic Formulants and Heavy Metals in Glyphosate-based Herbicides

THIRD WORLD NETWORK BIOSAFETY INFORMATION SERVICE

Dear Friends and Colleagues

Toxic Formulants and Heavy Metals in Glyphosate-based Herbicides

The major pesticides of the world are glyphosate-based herbicides (GBH), and their toxicity is highly debated. GBH are mixtures of water, with commonly 36–48% glyphosate claimed as the active principle. As with other pesticides, 10–20% of GBH consist of chemical formulants. They are mainly families of petroleum-based oxidized molecules, such as polyoxyethylenamines (POEA) and other contaminants. However, their composition is considered confidential business information which does not allow scientists to describe their mechanism of action either on non-target organisms or even on plants. These formulants are declared as inert by manufacturers.

To understand their mode of action, the comparative herbicidal and toxicological effects of glyphosate alone and 14 of its formulations on plants and human cells were studied. Glyphosate was found to be only slightly toxic on plants at the recommended dilutions in agriculture, in contrast with the general belief. In the short term, the strong herbicidal and toxic properties of its formulations were exerted by the POEA formulant family alone.

Tested on human cells, the formulations were found to have a more endocrine disruptive effect and were even highly more toxic than glyphosate. The study also identified the presence of the heavy metals, arsenic, chromium, cobalt, lead and nickel, which are known to be toxic and endocrine disruptors, as contaminants in 22 pesticides, including 11 glyphosate-based ones. This could also explain some of the adverse effects of the pesticides.

In in vivo chronic regulatory experiments that are used to establish the acceptable daily intakes of pesticides, glyphosate or other declared active ingredients in pesticides are assessed alone, without the formulants. Considering these new data, this assessment method appears insufficient to ensure safety. These results thus also shed new light on the toxicity assessment of genetically modified plants tolerant to Roundup (a GBH) because they could contain high levels of toxic formulants.

With best wishes,

TOXICITY OF FORMULANTS AND HEAVY METALS IN GLYPHOSATE-BASED HERBICIDES AND OTHER PESTICIDES

N. Defargea, J. Spiroux de Vendômoisb, G.E. Séralini

Toxicology Reports
Volume 5, 2018, Pages 156-163
https://doi.org/10.1016/j.toxrep.2017.12.025
December 2017
https://www.sciencedirect.com/science/article/pii/S221475001730149X

Abstract

The major pesticides of the world are glyphosate-based herbicides(GBH), and their toxicity is highly debated. To understand their mode of action, the comparative herbicidal and toxicological effects of glyphosate (G) alone and 14 of its formulations were studied in this work, as a model for pesticides. GBH are mixtures of water, with commonly 36–48% G claimed as the active principle. As with other pesticides, 10–20% of GBH consist of chemical formulants. We previously identified these by mass spectrometry and found them to be mainly families of petroleum-based oxidized molecules, such as POEA, and other contaminants. We exposed plants and human cells to the components of formulations, both mixed and separately, and measured toxicity and human cellular endocrine disruption below the direct toxicity experimentally measured threshold. G was only slightly toxic on plants at the recommended dilutions in agriculture, in contrast with the general belief. In the short term, the strong herbicidal and toxic properties of its formulations were exerted by the POEA formulant family alone. The toxic effects and endocrine disrupting properties of the formulations were mostly due to the formulants and not to G. In this work, we also identified by mass spectrometry the heavy metals arsenic, chromium, cobalt, lead and nickel, which are known to be toxic and endocrine disruptors, as contaminants in 22 pesticides, including 11 G-based ones. This could also explain some of the adverse effects of the pesticides. In in vivo chronic regulatory experiments that are used to establish the acceptable daily intakes of pesticides, G or other declared active ingredients in pesticides are assessed alone, without the formulants. Considering these new data, this assessment method appears insufficient to ensure safety. These results, taken together, shed a new light on the toxicity of these major herbicides and of pesticides in general.