Is the UK coming clean on pesticides?

| 2nd October 2017
Certain pesticides have been found to kill or damage a wide range of pollinating insects, including honeybees. (c) Louise Docker
Certain pesticides have been found to kill or damage a wide range of pollinating insects, including honeybees. (c) Louise Docker
Following recent headlines and new scientific papers PETER MELCHETT of the Soil Association reports on the evolving dialogue around pesticides.
Pesticides are under greater scrutiny now than in any period since they became widely used in the 1960s.

The use of toxic chemicals by farmers to control unwanted plants, insects and fungal disease in their crops is under greater scrutiny now than in any period since they became widely used in the 1960s. The most used weedkiller in the world, glyphosate (sold by Monsanto as Roundup), has been the focus of extraordinary attention ever since a UN agency, the IARC, declared it a probable human carcinogen two years ago.

Over the same period, the world's most widely used insecticides, neonicotinoids, have been under attack because they have been found to kill or damage a wide range of pollinating insects, including honeybees. Both controversies have stimulated a great deal of new scientific research, and those findings, along with revelations of cover-ups, the abuse of science and suppression of evidence in internal Monsanto documents published in US court cases, are building increasingly strong cases against these chemicals.

Defending the role

Glyphosate use has greatly increased globally, partly as a result of its being tied to the use of GM crops in the US, Canada and Latin America, and partly because it is now widely used in countries like the UK to dry and kill cereal and oilseed rape crops just before harvest. This widespread use, particularly on food crops just before they are harvested, has led to further evidence of the effects of glyphosate on life in the soil and on human health.

Neonicotinoid insecticides have spread rapidly, because they are easily applied as a seed coating, and from there they are absorbed into every part of the plant, killing insects throughout the plant's life. However, up to 95% of the active ingredient can end up in the soil rather than the plant, and from there make its way to wildflowers growing alongside fields, and waterways – proving lethal to insects feeding there.


Throughout this, the UK Government has played its usual role in EU debates about pesticide safety, stoutly defending existing pesticides, refuting mounting scientific evidence of danger, and insisting that current regulatory approvals should be maintained. In these debates, the Chief Scientist at Defra, Professor Ian Boyd, has played important role in defending the UK position. Given his defence of these individual pesticides, it is all the more remarkable, and welcome, that he has just published a paper with a colleague, Alice Milner, which baldly states that the ‘assumed safety of widespread pesticide use is false’.


Professor Boyd and his colleague base their criticism on the widespread use of pesticides, some of it clearly prophylactic (as indeed must be the case with almost all pesticides applied as seed treatments, like neonicotinoids), and the complete absence of monitoring after regulatory approval. They deplore ‘The lack of any limit on the total amount of pesticides used and the virtual absence of monitoring of their effects in the environment’ saying that this ‘means it can take years for the impacts to become apparent’.  Of course, this does (conveniently) excuse the UK’s failure to object to these pesticides before now, on the basis that their impact had not yet ‘become apparent’, but it is still a dramatic, and welcome, change of tune.

The problems identified by Boyd and Milner aren't the only failings in the current regulatory process. Those interested in the safety of pesticides have long argued that another gaping hole in the safety process is that only a single active ingredient is checked by regulators, and safety levels, known as the Maximum Residue Level (MRL) are set for that particular toxic chemical. Yet in reality people eat a mixture of pesticides in their food, indeed a mixture that is growing in complexity every year. No MRLs are set for mixtures – cocktails – of pesticides in our food. Nor is any account taken of the possibility that some pesticides, those that are designed to attack fungal diseases in particular, may greatly exacerbate the impact of other toxic pesticides.

Toxicity of pesticides

New science has shown that ingesting one pesticide after another may also increase their impact, and also that existing techniques may miss subtle impacts that pesticides can have at very low doses, well below the MRL. Finally, not only do regulators ignore the need to set safe levels for the mixtures of pesticides people actually eat with their food, they also ignore the numerous other chemicals applied with a pesticide, for example to help it flow through the sprayer more easily, or to encourage it to stick to the plant, even though it is known that some of these additional chemicals may greatly increase the toxicity of the pesticide.


Professor Ian Boyd's recognition of the yawning gap between what is considered reasonable in checking for the safety of medicines, particularly the need to carefully monitor what happens when they start to be used on patients, compared to the total absence of monitoring of the impacts of pesticides have on the environment, and of course on human health, is very welcome. The issues he has raised, and others now at last beginning to emerge after 60 odd years of widespread pesticide use, will be debated at an important conference at the Royal Society of Medicine on 20th November (Pesticides and food: Is low dose exposure harmful?), with responses from farmers and the pesticide industry.  Professor Boyd has made an important contribution to a debate that is just getting going.


This Author

Peter Melchett has been Policy Director of the Soil Association, the UK's main organic food and farming organisation, working on campaigns, standards and policy, since 2001. He runs an 890-acre organic farm in Norfolk, with beef cattle and arable seed crops. 


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