Weedkiller chemical glyphosate fear over 'healthy' wholemeal bread wheat
Bread sold in the UK is being contaminated with a "probably" carcinogenic weed killer chemical because of a farming practice that should be banned, campaigners have claimed.
Wholemeal bread, usually seen as a healthy food choice, may be most affected since it contains more of the wheat grain.
The Soil Association is calling on the Government, farmers, the milling industry and supermarkets to ensure bread containing glyphosate residue is taken off store shelves.
It argues that consumers should be protected despite levels of the chemical traces being well below the current European safety threshold, set before new information about the potentially toxic effects of glyphosate emerged.
In March, a World Health Organisation report published in The Lancet Oncology journal concluded that the chemical "probably" caused cancer in humans, based on a thorough review of scientific evidence.
However the finding is controversial and has been dismissed as invalid by German regulators.
Glyphosate is the chief ingredient in Roundup, the world's most widely used herbicide, made by the agritech company Monsanto.
Its appearance in bread is blamed on the increasing treatment of wheat with pesticides just before harvesting.
Soil Association policy director Peter Melchett said: "We cannot ignore the World Health Organisation's findings that glyphosate is a probable cause of cancer - the risks are too great.
"In recent years nearly a third of British bread tested by the Government contained glyphosate. Although the quantities found are well below the official safetly level, this limit was agreed before the latest scientific findings about the dangers of glyphosate.
"The Soil Association is calling for an immediate stop to glyphosate sprays on wheat destined for use in bread. The glyphosate spraying season starts now, and in the interests of human health and the quality of British bread, the Government needs to call a halt to the spraying before it starts."
Bread samples tested by the Expert Committee on Pesticide Residues in Food , which advises the Department of Environment, Food & Rural Affairs (Defra), in 2013 and 2014 found an average of 0.2 milligrams of glyphosate per kilogram.
The Maximum Residue Level (MRL) set by the EU is much higher - 10 milligrams per kilogram. However, campaigners insist that no limit can now reliably be viewed as safe.
In 2013 just under a third (30%) of bread tested contained a measurable amount of glyphosate. The proportion dipped to around 15% the following year.
Other Government figures show that glyphosate use on British farms has increased four-fold in the last two decades, the Soil Association said .
In 2013, a record 800,000 kilograms of the chemical was sprayed on just over a million hectares of British farmland, including nearly a third of cereal crops grown in the UK.
Herbicides are used just before harvesting not to kill weeds but to stop further growth of the wheat and keep it dry.
The practice cuts costs and makes mechanised reaping with combine harvesters more efficient.
Mr Melchett maintained that the extra cost of not carrying out pre-harvest spraying was "marginal".
He added: "It's much more about convenience than economics, and it's convenience without giving any thought to what effect it is having on food.
"The use of glysophate in the UK is clearly increasing because of this pre-harvest use. And if you spray something right before you harvest it the chances of chemicals appearing in food are obviously going to be higher."
Mr Melchett said wholemeal bread was more likely to pick up glysophate residues because it was made with the outer layer of the wheat grain.
At a briefing held in London one of the scientists who co-authored the WHO International Agency for Research on Cancer (IARC) report said there was "credible" evidence that exposure to glyphosate might trigger the blood cancer Non-Hodgkins Lymphoma.
Stronger links with different types of cancer had been shown in animals studies, said Professor Christopher Portier, from the US National Academy of Sciences. Overall the risk from glyphosate was at "Group 2A" level, meaning that it "probably" but not definitely was a cause of cancer in humans.
Prof Portier said: "Glyphosate is definitely genotoxic (damaging to DNA). There's no doubt in my mind that it's a genotoxic chemical."
Another scientist, Dr Robin Mesnage, from King's College London, said the effect of other chemicals mixed with glyphosate in Roundup formulations had not been properly taken into account.
He had carried out tests on human cell lines showing that the commercial product was 1,000 times more toxic than glyphosate alone.
Yet the "adjuvant" chemicals used to stabilise and enhance the effect of the weed killers were regarded as "inert" by regulators.
"This different cell toxicity is generalisable to at least 10 cell types," said Dr Mesnage. "More tests are needed. Glyphosate and its commercial formulations have to be tested at an environmental level. This has never been done."
Monsanto's UK spokesman Mark Buckingham said: "Glyphosate is not a carcinogen, and regulatory agencies have been clear for decades that all labelled uses of glyphosate, including pre-harvest use by farmers, are safe for human health.
"Pre-harvest use of glyphosate is a valuable tool for farmers in a variety of circumstances. Research has consistently shown that in the rare instances that glyphosate residues are detected in wheat, the levels are so small as to be completely negligible, and no evidence presented by the Soil Association changes this."
Alex Waugh, from the National Association of British and Irish Millers, which represents the flour industry, said: "The UK Government surveys glyphosate residues in bread every year and most of the bread doesn't contain detectable residues. Where they are present, they're well below the regulatory limit.
"I'm not going to say there's no problem with glyphosate, but there probably isn't a problem with glyphosate and bread right now.
"The millers and bakers will continue to talk to their suppliers and ask what can be done to minimise these residues. But if the choice is to have a crop that you can turn into bread and not having one then I'd rather have the crop."