Facts and Fallacies in the Debate on Glyphosate Toxicity

Abstract

The safety profile of the herbicide glyphosate and its commercial formulations is controversial. Reviews have been published by individuals who are consultants and employees of companies commercializing glyphosate-based herbicides in support of glyphosate’s reapproval by regulatory agencies. These authors conclude that glyphosate is safe at levels below regulatory permissible limits. In contrast, reviews conducted by academic scientists independent of industry report toxic effects below regulatory limits, as well as shortcomings of the current regulatory evaluation of risks associated with glyphosate exposures. Two authors in particular (Samsel and Seneff) have published a series of commentaries proposing that long-term exposure to glyphosate is responsible for many chronic diseases (including cancers, diabetes, neuropathies, obesity, asthma, infections, osteoporosis, infertility, and birth defects). The aim of this review is to examine the evidential basis for these claimed negative health effects and the mechanisms that are alleged to be at their basis. We found that these authors inappropriately employ a deductive reasoning approach based on syllogism. We found that their conclusions are not supported by the available scientific evidence. Thus, the mechanisms and vast range of conditions proposed to result from glyphosate toxicity presented by Samsel and Seneff in their commentaries are at best unsubstantiated theories, speculations, or simply incorrect. This misrepresentation of glyphosate’s toxicity misleads the public, the scientific community, and regulators. Although evidence exists that glyphosate-based herbicides are toxic below regulatory set safety limits, the arguments of Samsel and Seneff largely serve to distract rather than to give a rational direction to much needed future research investigating the toxicity of these pesticides, especially at levels of ingestion that are typical for human populations.

Identification of the first glyphosate transporter by genomic adaptation

“…As a soil bacterium B. subtilis can get into contact with growth-inhibiting substances like antibiotics and herbicides, which may be of anthropogenic origin. Moreover, due to the fact that glyphosate is toxicologically safe and that transgenic, glyphosate-resistant crops have been introduced, the herbicide has become the dominant 'Weedkiller' worldwide (Li and Long, 1988;Duke and Powles, 2008;Arjó et al, 2013;Benbrook, 2016;Mesnage and Antoniou, 2017;Tincher et al, 2017;see below). Glyphosate is resistant to chemical hydrolysis, thermal decomposition and photolysis due to a stable C-P bond (Kononova and Nesmeyanova, 2002).…”

“…Glyphosate is resistant to chemical hydrolysis, thermal decomposition and photolysis due to a stable C-P bond (Kononova and Nesmeyanova, 2002). Moreover, due to the fact that glyphosate is toxicologically safe and that transgenic, glyphosate-resistant crops have been introduced, the herbicide has become the dominant 'Weedkiller' worldwide (Li and Long, 1988;Duke and Powles, 2008;Arjó et al, 2013;Benbrook, 2016;Mesnage and Antoniou, 2017;Tincher et al, 2017;see below).…”

Re-registration Challenges of Glyphosate in the European Union

“…Some of these findings have been questioned by Monsanto (Acquavella et al, 1999) and a recent cohort prospective epidemiology study carried out in the US on 57310 licensed pesticide applicators and 32347 spouses in Iowa or North Carolina States found no apparent correlation between glyphosate use and solid tumor or lymphoid malignancies, including non-Hodgkin lymphoma, except for increased risk of acute myeloid leukemia in case of high exposure (Andreotti et al, 2018). Alleged attribution of certain chronic diseases (e.g., diabetes, neuropathies, obesity, asthma, infections, osteoporosis, infertility) to long-term exposure to glyphosate were judged unreasonable (Mesnage and Antoniou, 2017), but extremely low levels of a glyphosate-based herbicide (Roundup R ) have been shown in a multiomics study to possibly correlate to the development of metabolic syndrome, causing marked alterations of the liver proteome and metabolome revealing the presence of non-alcoholic fatty liver disease and its progression to non-alcoholic steatohepatosis (Mesnage et al, 2017b).…”

Synthetic biology yields a dinuclear copper based antibody for the naked-eye detection of glyphosate

“…It has attracted increasing attention over the past decades due to its presumed toxicity generating various diseases such as for example: cancers, neuropathy, obesity, infections, infertility, birth defects, etc. [1] Various methods for the detection of glyphosate are reported in the litterature such as; blablabla. A sub-group of them rely on chemoreceptors.…”