May 19, 2016

expert reaction to EU decision to delay a vote on glyphosate

The EU has delayed a vote which would determine whether it continues to allow sales of products containing the pesticide glyphosate.

Dr Crispin Halsall, Reader in Environmental Organic Chemistry at Lancaster University, said:

“Glyphosate is the active herbicide found in many ‘over the counter’ garden weed killer products and it’s also the most widely used herbicide in general agriculture. The chemical mirrors the simple amino acid – glycine – and therefore interferes with protein biosynthesis affecting the rapidly growing parts of plants. Although not a persistent chemical its very wide use means that it is present in water courses and reservoirs and it has been detected in common foodstuffs.

“Glyphosate exposure to the general public can be considered to be very low but given IARC’s careful assessment of glyphosate as a group-2A human carcinogen, then there needs to be a thorough review into what is deemed to be the acceptable or tolerable daily intake of glyphosate in our diet and whether this is indeed tolerable in light of the IARC’s assessment. Furthermore, given the wide range of often conflicting scientific evidence about the harmful effects of glyphosate, then regulators need to learn from the field of medicine and introduce systematic review techniques for assessing and appraising scientific evidence to draw firm conclusions regarding the risk of harm from glyphosate exposure and assuage public anxiety. In turn, this approach may also help agri-industry and lead to better use-management practices to reduce unwanted contamination of the wider environment and human foodstuffs.”

Dr Paul Neve, Weed Biologist at Rothamsted Research, said:

“Glyphosate is a critical component of current integrated weed management strategies in agricultural crops in the UK and across Europe. It is one of the last remaining herbicides for effective control of black-grass due to evolution of resistance to most other herbicides.

“Black-grass control is the number one crop protection issue on UK arable farms, severely impacting crop yields. Loss of glyphosate would severely undermine current best management practices.

“Glyphosate is a key tool in no-tillage farming systems, which have considerable benefits for soil structure and soil health.

“Decisions on future glyphosate registration have to take full account of the economic and environmental consequences across farms, both nationally and within the EU.”

Dr Oliver Jones, Senior Lecturer in Analytical Chemistry at RMIT University in Melbourne, said:

“The EU vote, or rather the lack of one, is not unexpected and is possibly understandable.  But as it seems mostly based mainly on the recent IARC ruling, it should at least be considered by both policy makers and the public that the IARC only asks if things cause cancer or not. They take no account of how much of something is needed to have an effect.

“For example the IARC classifies glyphosate as ‘probably carcinogenic to humans’. However, they also classify sunlight and alcohol (amongst others) as ‘definitely carcinogenic to humans’. At face value this means sunlight and beer, wine and spirits are not only carcinogens, they are worse than glyphosate. I doubt however, that the EU will stop licensing the sale of alcoholic drinks anytime soon.

“A ban on the use of glyphosate will also not stop weeds growing, so if glyphosate was banned alternative pesticides would have to be used – for which the risks may or may not be as well known. The question the EU committee members should perhaps ask is, does glyphosate cause a significant cancer risk at the levels to which people are exposed to it? The U.N.’s Food and Agriculture Organisation, the World Health Organisation (parent body to the IARC) and the European Food Safety Authority all suggest not.”

Dr Christopher Connolly, Reader in Neurobiology at the University of Dundee, said:

“The failure of the PAFF Committee to reach a qualified majority on the issue of glyphosate use sends a strong message that more scientific knowledge is required on the hazard/risk of glyphosate to both human health and the environment. Until this evidence is convincing, one way or the other, glyphosate may no longer be authorised for use in the EU. Clearly, the authorisation process requires a more robust framework, on which sound decisions can be made.

“The research should be performed much earlier in the process of authorisation, with the evidence being produced by independent laboratories, the data made available to the scientific community, and the cost met by the producer.”

This quote was written before the announcement

Prof. David Coggon, Professor of Occupational and Environmental Medicine at the University of Southampton, said:

“IARC classified glyphosate as probably having the potential to cause cancer in humans.   This was based on evidence of carcinogenicity in animals and suggestions of an association with lymphoma in exposed people (mainly agricultural workers). IARC recognised that the epidemiological evidence for a risk in humans was only weak.  Importantly, the IARC classification concerned hazard – i.e. the potential for the chemical to cause cancer in humans in at least some circumstances. It did not, however, address the relationship of risk to levels of exposure. A chemical might cause cancer at extremely high exposure levels (as tend to be used in animal experiments), but pose no risk at all at the much lower levels of exposure which occur in real life.

“The critical question for regulatory authorities such as EFSA is not whether a chemical has any potential to cause cancer, whatever the circumstances, but whether it could pose a material risk of cancer at the maximum levels of exposure which could reasonably be expected from proposed uses of the chemical. Among other things, this will depend on what is known about the biological mechanisms by which the substance could lead to cancer. An assessment that a pesticide does not pose a material risk of cancer as used, is not incompatible scientifically with a view that it might cause cancer at much higher exposure levels.

“To give an analogy, alcohol is a definite cause of cancer in humans with clearly increased risks in people who are long-term high consumers. However, we do not as a consequence ban liqueur chocolates.”

Declared interests

Dr Halsall: None declared.

Prof. Coggon: I have not been involved in any of the recent assessments, but in the past I have been a member of IARC monograph groups on other chemicals and of the scientific committee at EFSA that advises on pesticides.

Dr Connolly: I have no declarations of interest.

Dr Jones: I have no competing interests to declare. I do not have (and have never received) any funding from any pesticide or chemical company. I have also had no input into the recent classifications of glyphosate. I am simply responding, as a scientist, to the evidence presented to date.