Damning review of the approval of Roundup herbicide

December 2012

Just before the safety of Roundup herbicide jumped into the spotlight (see GM MAIZE NOT SAFE TO EAT - News, October 2012), a review was published which explains how this damaging formulation found its way into our food chain.

The review focused on “Teratogenic Effects of Glyphosate-Based Herbicides: Divergence of Regulatory Decisions from Scientific Evidence” ('Roundup' is the most common commercial formulation of these glyphosate-based herbicides), and the lead author was medical toxicologist, Michael Antoniou.

In 2010, a key series of experiments revealed teratogenic effects due to Roundup in amphibians and chickens, two common models for human embryos. It was also demonstrated that the problem induced by Roundup was due to its disruption of the 'retinoic acid signalling pathway'. This cell communication pathway is a vital part of early development in virtually all vertebrates including humans. Since the EU approval of glyphosate in 2002, four further supporting studies of adverse effects from Roundup have been published.

As the 'rapporteur' country for glyphosate's original EU approval, Germany was asked to re-assess the chemical's safety in light of the new evidence. In an anonymous review of its own previous opinion, the German food safety regulators (BVL) stated:
“There is a huge and reliable database for developmental toxicity of glyphosate and no evidence of teratogenicity has been obtained. In particular, studies in rats and rabbits failed to reveal craniofacial malformations as ... would be expected if a substance affects mainly the neural crest.” 
(Note. Cells from the 'neural crest' area give rise to craniofacial cartilage and bone, and form a major part of nervous tissue in vertebrates)

BVL concluded that the findings “do not put the current risk assessment for glyphosate and glyphosate-based (pesticides) into question with regard to human health.”

This 'huge and reliable database' isn't available for inspection because it was largely commissioned by manufacturers of glyphosate: it is 'commercially confidential', and neither published nor peer-reviewed.

In 2012, the European Food Safety Authority (EFSA) should have carried out a routine 10-year re-appraisal of glyphosate. However this hasn't happened, despite other recent concerns raised, because the body is over-stretched and under-resourced, and the re-appraisal has been deferred until 2015.

The authors examining this whole sorry story have only been able to access BVL's draft assessment from 1998. They summarised the experiments used to pronounce glyphosate 'safe':
  • There are eleven studies carried out between 1980 and 1993.
COMMENT Note that these studies did not have the benefit of the sophisticated techniques available today to examine, for example, retinoic acid signalling or gene activity.
  • Four of the publications were found to be poorly described or reported, or to present conflicting data. Note that these deficiencies and their questionable reliability did not prevent them from being used in BVL's assessment.
  • Every study records malformations of the skeleton, heart, or lungs, or reports embryo or maternal deaths. There's also some evidence of a dose-response operating in all tests where a range of glyphosate concentrations were administered.
  • In the seven acceptable studies, five used rabbits and three used rats. Since malformation and deaths were evident in the rabbits at a fraction of the doses of glyphosate given to rats, rabbits are clearly a much more sensitive model to work with. Since the main purpose of BVL's risk assessment was to establish an acceptable daily intake (ADI, see box) of glyphosate for humans, the question of sensitivity is paramount.
  • All the studies tested glyphosate, not Roundup, which has repeatedly been found to be more toxic than its herbicidal ingredient. Neither did any study include 'AMPA' which is the most common derivative of glyphosate found in the environment, and which is also toxic.

Note: Acceptable Daily Intake (ADI) 
The ADI is worked out from the highest dose at which no harm has been detected during animal tests. This dose is then reduced by a safety factor of 100 to establish an ADI. It's unit of measurement in the case of glyphosate is milligrams per kilogram of body weight, mg/kg/bw.

Antoniou's team mentions a number of unconvincing arguments used to dismiss the negative findings, for example:
  • Problems at high doses of glyphosate are put down to maternal toxicity in which the foetus is bound to be harmed because the dam is diseased. However, no attempts have been made to distinguish between the two, and toxin concentrations weren't stepped up gradually in the experiments: glyphosate could be harming both the mother and the pups, with the latter being more sensitive and affected at much lower exposure levels of the chemical.
  • A lack of clear linear dose-response symptoms has been used as a 'gold-standard' proof of toxicity. This is not in accord with current scientific understanding, in which for example endocrine effects, the exact timing of foetal exposure, stress-levels etc. can alter the symptoms.
  • Unspecified, possibly invalid, and definitely unscientific historical 'controls' are used to pretend nothing unusual is actually happening.
BVL arrived at an ADI for glyphosate of 0.3 mg/kg/bw. However, this seems to have been based on the rat studies. The (more sensitive) rabbit studies suggest an ADI of 0.1 mg/kg/bw. Since these are tests of glyphosate, and Roundup is much more toxic, the ADI for what we are actually consuming is likely to be closer to 0.025 mg/kg/bw. To put this into a practical perspective, a study of farming and non-farming families in Iowa suggested a real-life urinary burden of 0.9 mg/kg/bw.

Antoniou also describes population studies in areas where there is large-scale use of Roundup on GM crops. These include:
  • In Paraguay, malformations in the offspring of women exposed to pesticides during pregnancy included craniofacial defects, anencephaly, microcephaly, hydrocephalus, myelomeningocele, cleft palate, anotia, polydactyly, syndactyly and congenital heart defects.
Note. Many of these defects are of the type associated with disturbances in the retinoic acid signalling pathway.
  • In Argentina, chromosomal aberrations were observed, and malformations in the offspring of women exposed to pesticides during pregnancy included spina bifida, microtia, cleft lip with cleft palate, polysistic kidney, postaxial polydactyly and Down's syndrome.
  • In Ecuador, DNA damage was observed.
  • In Canada, a higher incidence of miscarrriage and pre-term delivery were evident, and ADHD in children.
Note. Miscarriage is the normal outcome of malformations in the embryo. ADHD could be a result of neurological disturbance.


If it seems to you that this account describes a food-safety regulatory set up which is industry-friendly, cherry-picking out-of-date invalid science unchallenged, and may be poisoning you, that's probably because it is.

The EFSA has given a green light to the cultivation of two varieties of GM Roundup Ready soya in the EU: this is also a green light to fertility problems, birth defects, chronic disease and cancer, in rural communities and beyond.

Demand a glyphosate-free, Roundup-free, GM-free environment, and glyphosate-free, Roundup-free, GM-free food, because anything else is unacceptably harmful to your health.

Also consider contacting your MEP to insist that the 10-year appraisal of glyphosate must be carried out as a matter of urgency, and that it should include all the Roundup formulations of glyphosate actually used. It might also be good to hint that the next appraisal should be carried out by a body other than the original rapporteur.

  • M. Antoniou, et al., 2012, Teratogenic Effects of Glyphosate-Based Herbicides: Divergence of Regulatory Decisions from Scientific Evidence, Journal of Environmental and Analytical Toxicology, 23.06.12
  • EFSA favours cultivation of 'Roundup Ready Soy' with the EU,, 22.06/12

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