From horse meat in beef burgers to the threat of chlorinated chicken, Britain has had its fair share of food scares over the past decade.
According to data from the Food Standards Agency, a third of us now have serious concerns about the safety of what we eat. Top of that list of concerns are pesticides – used in commercial food production to increase yields by killing pests and strangling weeds.
A damning new report by Britain’s leading food and farming organisation, the Soil Association, said modern intensive farming methods mean we’re exposed to traces of ‘cancer-causing’ compounds left on fruit and veg. Some items, it said, are contaminated with up to 14 chemicals, a phenomenon dubbed ‘the pesticide cocktail effect’.
According to data from the Food Standards Agency, a third of us now have serious concerns about the safety of what we eat. Top of that list of concerns are pesticides – used in commercial food production to increase yields by killing pests and strangling weeds
And with a recent ban on the most commonly used pesticide in the UK – chlorothalonil, an anti-fungal chemical used on crops including wheat, barley and asparagus – due to links to cancers and skin conditions, it’s no wonder that British shoppers are concerned.
So are pesticides a genuine risk to our health? We asked leading scientists.
Balancing killing bugs and keeping us safe
Agricultural chiefs draw on scientific evidence to establish ‘maximum residue levels’ for every pesticide. Residue levels take into account effectiveness – the chemicals are used to ward off harmful bugs that can destroy food – balanced against the safety of those exposed to the pesticide on farms, as well as environmental concerns and consumer safety. In most cases the maximum residue level is hundreds, if not thousands of times lower than the level at which adverse health effects would be seen.
Traces of pesticide… but now harm to health
Pesticide traces were found in 45 per cent of 3,385 samples of food and drink bought in the UK in 2018, according to The Expert Committee on Pesticide Residues in Food.
Citrus fruits, strawberries, pears, grapes, apples, parsnips and asparagus were the fruit and veg most frequently contaminated by pesticides over the past five surveys. Avocados, beetroot, sweetcorn, mushrooms, onions and sweet potatoes were among the crops most likely to test as pesticide-free.
But if pesticides are found, it is usually in tiny amounts. ‘Improved detection technology means foods may be reported as containing residues, when they would have come up clean previously,’ says Alan Boobis, Emeritus Professor of Toxicology at Imperial College, London.
‘About three per cent of samples exceeded the maximum residue level in 2018. Action is taken in these cases, but we are still talking about a level that is far below one that’s an issue for health.’
Today, 250 active pesticide substances are regulated and allowed for use in the UK and EU – 1,000 fewer than 20 years ago, before the current approval regime
Today, 250 active pesticide substances are regulated and allowed for use in the UK and EU – 1,000 fewer than 20 years ago, before the current approval regime. And now, although more crops are being treated with chemicals, less is used – there is a smaller quantity on our food. The UK regulators say this is due to restrictions on older pesticides and modern, efficient methods of application.
No proof of the ‘cocktail effect’
The Soil Association report triggered concern about what it called ‘the pesticide cocktail effect’ – the idea that two or more pesticides are more harmful than the sum of their individual effects.
Should we be worried? David Coggon, Emeritus Professor of Occupational and Environmental Medicine at the University of Southampton, says there is little evidence to suggest we should be.
‘When chemicals are encountered in doses close to those at which they can individually cause toxicity, there can be interactions between them,’ he says. ‘But in the case of pesticides where exposures are at levels well below the threshold for toxicity of each chemical, this is not expected to occur.’
Two recent EU risk assessments looked at the potential cocktail effect of pesticide residues on the thyroid and nervous system. They concluded that across Europe, cumulative exposure is below the threshold that would trigger regulatory action – you’d have to eat an entire orchard’s worth of fruit and veg to experience any effects.
Five a day won’t cause cancer
In 2019, US couple Alva and Alberta Pilliod were awarded £1.5 million when a jury ruled that the weedkiller Roundup was responsible for their non-Hodgkin’s lymphoma, an immune system cancer.
Glyphosate, the main ingredient in Roundup, was the most extensively used weedkiller on UK farms in 2018, according to the Pesticide Usage Survey.
Glyphosate, the main ingredient in Roundup, was the most extensively used weedkiller on UK farms in 2018, according to the Pesticide Usage Survey
However, the ruling was based on one opinion from the International Agency for Research on Cancer that glyphosate was ‘probably carcinogenic’. The risks associated with exposure are largely occupational – due to being inhaled or absorbed by farm workers – rather than related to residues in food.
The US Environmental Protection Agency, together with expert panels and regulatory authorities across the world, say the chemical does not cause cancer.
‘The evidence doesn’t support pesticide residues causing cancer,’ says British Dietetic Association spokesman Helen Bond. ‘I’d be worried if people ate fewer fruits and vegetables, or struggled to afford organic veg because they believed there was a link.’
Natural doesn’t always mean safe
Bizarrely, not spraying with pesticides could make vegetables toxic. Plants naturally produce chemicals in response to attacks from insects or harmful microbes – and these chemicals can be harmful to humans.
In New Zealand in 2003, an unusually vicious aphid attack led to unsprayed vegetables protecting themselves by producing toxic chemicals called cucurbitacins. This led to some people who ate them being admitted to hospital.
And natural oils such as citronella and clove, which are used widely in organic agriculture, aren’t necessarily less toxic than synthetic additives, as they contain naturally occurring substances that, at high doses, can lead to serious skin rashes and irritation on contact.
Organic food has food has Pesticides too!
IF man-made agri-chemicals are so potentially toxic in the wrong doses, surely going organic is the answer? But organic veg is sprayed with chemicals, too. Organic farmers have 30 different pesticides they can use, according to EU law.
In 2018, 17 of 351 organic samples tested by UK agricultural chiefs contained pesticide residues – most not allowed in organic farming.
One sample of an organic oat-based cereal for toddlers was found to have pesticide residue above the maximum amount allowed in baby food.
Organic farmers have 30 different pesticides they can use, according to EU law
