We eat it in our food and spray it on our gardens and allotments. It is all over our parks and farmers’ crops.

Roundup is the UK’s most widely used weedkiller and globally the most popular in history.

When the U.S. company Monsanto launched the product in 1974, its marketing men proclaimed it to be a technological breakthrough that killed almost every weed without harming humans or the environment.

But since the Nineties, the safety of Roundup — and its active ingredient glyphosate — has been challenged by studies that suggest that the weedkiller is linked to serious conditions including liver and kidney disease, infertility, birth abnormalities and cancer.

Healthy? The safety of Roundup's active ingredient, glyphosate, has recently been challenged

Nevertheless, its use in UK farming has increased by an astonishing 400 per cent in the past 20 years, government figures show.

One-third of Britain’s crop-growing land is now treated with glyphosate (Monsanto’s patent for Roundup has expired, but while there are now more than 20 suppliers of glyphosate in Europe, Roundup remains the market leader, earning it some £1.5 billion a year worldwide).

Now its use is effectively being challenged in a landmark legal case in America.

In San Francisco, DeWayne Johnson, 46, a father of three and former school groundsman, is taking Monsanto to court.

He has a form of non-Hodgkin lymphoma, a cancer of the white blood cells that caused cancerous lesions to form over most of his body. Doctors say he may have only months to live.

Johnson says he developed symptoms after he was twice accidentally drenched in Roundup while spraying schoolyards at work. He also had the chemical waft regularly into his face.

His lawyers have claimed in court that Monsanto has known for decades that Roundup is carcinogenic but didn’t disclose it.

There is sparse clinical research to support Johnson’s claims about a specific link between Roundup and his non-Hodgkin lymphoma.

In 2014, a meta-analysis of previous studies, published in the International Journal of Environmental Research and Public Health, found only a ‘handful’ of papers that reported associations between glyphosate and non-Hodgkin lymphoma.

COUNTRIES THAT HAVE BANNED HERBICIDE

The analysts, from the International Agency for Research on Cancer in Lyon, France, said that much more research is needed to establish whether an actual cause-and-effect link exists between the herbicide and this type of cancer.

However, in courts across the U.S. more than 400 other people are suing the chemical giant in a class-action lawsuit which says that they or their deceased family members contracted non-Hodgkin lymphoma caused by contact with Roundup.

The cases are the culmination of years of litigation and weeks of court hearings about the controversial science surrounding the safety of glyphosate.

Did you know? One-third of Britain’s crop-growing land is now treated with glyphosate

Monsanto is fighting the claims vigorously, saying that there is no evidence for a cancer link.

But should we be sufficiently worried by Roundup and other glyphosate weedkillers to avoid using them in our gardens?

Some European countries are deeply concerned about the chemical’s possible effects on humans and the environment. In January, Germany’s government agreed to begin the process of banning glyphosate over safety fears — and in April its agriculture minister said she was finalising a resolution to end its use in household gardens, parks and sports facilities, with further plans to set ‘massive’ limits for its use in agriculture. Last year the Belgian government banned domestic gardeners from using it.

Portugal prohibited glyphosate’s use in all public spaces two years ago. Last November, President Emmanuel Macron announced that France would ban it outright within three years.

Such laws have been prompted by evidence such as a study in the journal Food and Chemical Toxicology in 2013, which warned that glyphosate can, in lab studies, cause human breast cancer cells to proliferate up to 13 times faster than normal.

Glyphosate seems to act as a synthetic form of the female hormone oestrogen, according to the oncologists at Bangkok’s Environmental Toxicology Program who led the study. They suggested that this can accelerate the growth of forms of breast cancer that are fuelled by oestrogen.

Nevertheless, in Britain, the National Farmers’ Union is lobbying for glyphosate to be retained.

No.1: Roundup is the UK’s most widely used weedkiller and the most popular in history

At stake is not just the future of a weedkiller, but the claimed loss of nearly £1 billion annually to the UK economy, according to analysts at the Oxford University business agency, Oxford Economics. They argued last year that a ban would cut wheat production by a fifth, and oilseed rape by more than a third, because weed infestation would slow planting, growing and harvesting.

Along with other crop losses, this would wipe £930 million off Britain’s GDP, says the Oxford report, which was commissioned by the Crop Protection Association (a trade association of agricultural companies whose members include Monsanto).

But the chemical does not simply stay in cereal fields.

It lands on our plates, because farmers use glyphosate to kill their crops before harvesting (as well as prior to planting the seeds, when farm workers are required by law to wear protective clothing).

TRACES HIGHER IN BROWN BREAD

Dr Michael Antoniou, a biochemist and head of the Gene Expression and Therapy Group at King’s College London, told Good Health: ‘Farmers in the UK use it just before harvesting as a drying agent on cereals such as wheat, oats, barley and rape.

‘Days before harvesting they will spray Roundup to kill their crops, making the grain ripen quicker and dry more uniformly for storage,’ he explains. ‘The chemicals then go straight into the food chain because the grain is harvested so soon after spraying.’

Tests reported in 2014 by the Defra Committee on Pesticide Residues in Food found that almost two thirds of wholemeal bread sampled contained glyphosate. Ironically, ‘healthy’ wholemeal bread is more likely to contain glysophate residues because it is made with the outer layer of the wheat grain.

Last month, the Danish government introduced a ban on pre-harvest glyphosate spraying.

Concerns are compounded by the fact that in 2015 the World Health Organisation’s International Agency for Research on Cancer (IARC) classified glyphosate as ‘probably carcinogenic to humans’.

This should be viewed in context. In the same year, the IARC announced it was adding processed meats such as sausages, bacon and ham to its ‘highest risk’ category of carcinogens — a move that was widely criticised as alarmist.

Since then, however, reputable studies have added more cause for concern.

In June, for example, a study in the journal Archives of Toxicology revealed that pregnant rats exposed to the levels of glyphosate weedkiller found in soy beans breed grandchildren with physical abnormalities and fertility problems.

When these pups eventually gave birth, their offspring were undersized and had high levels of physical defects such as abnormally developed limbs and conjoined twins, report toxicologists at the National University of the Littoral in Argentina.

They say their findings reflect statistics showing that people living in an Argentine town in the heart of a soy and maize growing area, where glyphosate-based herbicides are sprayed in large amounts, experience birth defects at twice the national average rate.

Dr Antoniou describes the Argentinian findings as ‘new and unexpected’. His own research has revealed evidence of DNA damage to liver and kidneys in animal studies caused by Roundup.

His latest study, published last year in the highly respected journal Nature Scientific Reports, found that rats exposed to environmental levels of Roundup developed genetic abnormalities which indicated that their livers had developed non-alcoholic fatty liver disease and non-alcoholic hepatitis.

REVEALED: HOW TO GO SPRAY-FREE! Like most gardeners, I face a stark weed-fighting choice, writes John Naish: either run my allotment like a back-breaking version of The Good Life or apparently risk turning it into a toxic eden by liberally spraying scary-sounding chemicals. Studies show that it may take between a year and 16 months for glyphosate to leave your soil completely. As a glutton for punishment and healthy food, I choose the drudgery of hand-to-hand combat. The decision is inspired by a healthy dose of hypochondria informed by decades in medical journalism. So I was surprised to hear from a friend that the plot-holders on her London allotments are locked in debate about using glyphosate weedkillers on their crops. Is there still an argument? I won’t even use chemicals on the garden, for the sake of the pooch and kids. The Royal Horticultural Society website’s advises the following for a neglected allotment plot: ‘Treating with glyphosate-based weedkiller will bring the ground into a more workable condition.’ It’s important to stress there is no cast-iron evidence of risk, but garnishing your food with chemicals surely defeats the object of home-growing. In any event, in my hippie home town of Brighton you’ll get run off the plot for using glyphosate — literally. Health activists here have been campaigning since 2015 to rid the city of weedkiller chemicals. Other places around the country are doing the same. Instead we mostly work the worthy way. The easy thing is to put tarpaulins over unused weeded beds and keep everything covered all winter. Cruel darkness kills everything bar bindweed and dandelions. The rest is all hard work. Surrounding your crops with mulch — bark or grass clippings — likewise smothers weeds, though it does seem to import weeds of its own. Digging beds over annually helps to keep the blighters at bay. Obliterating young weeds with the sweep of a hoe is fun, until you chop through one of the plants you’re trying to protect. Pesticides can be shunned, too. I kill blackfly with very dilute eco washing-up liquid. I tell the kids that it makes them slip off plants. In fact it suffocates them. You do have to repeat the operation every few days, though. As for slugs, neighbour Pete seeds his ground with tiny nematode worms in spring — some 300,000 of them for every square metre of soil. The theory is that the worms infect the slugs lethally. But every spring a gastropod army marauds from my plot to his, delighted by the lack of crowds. Organic slug pellets may work, but my local super-slugs scoff at the things and leave a thank-you note for the amuse-bouches. I just stamp on the critters. It’s brutal but ecologically sound. You’re fighting a clean fight, but you have to realise that it’s a losing battle. And even if the crops do get laid waste by weed and worm, I reckon I’m still up on the deal — I hate the gym but I can spend hours on a shovel-wielding workout in the fresh air, any time of year. Advertisement

‘If these progressive diseases are not caught early enough they will progress to full-blown hepatitis, cirrhosis or liver cancer,’ Dr Antoniou told Good Health. ‘We also found evidence of kidney damage and imbalances of the hormonal system. There was evidence of neurological damage and developmental defects.’

He studied Roundup specifically rather than glyphosate alone, because he believes other chemicals in the Monsanto product, called adjuvants, may contribute to disease in humans.

LAB TESTS RAISE HEALTH CONCERNS

For weedkillers to work, they must break through the waxy surface of leaves to enter the plant cells. Adjuvants are chemicals that break down this waxy defence.

‘On the packaging these adjuvants are called “inert”,’ says Dr Antoniou. ‘But my lab evidence shows herbicides contain cocktails of adjuvants that may be toxic in their own right. Often they slip through uninvestigated. The regulations do not cover that part of the herbicide.’

Nevertheless, one adjuvant is now officially labelled as hazardous. It is called polyethoxylated tallow amine (POEA). In 2016 the European Union banned its use, after studies indicated that POEA might raise the risk of cancer in humans.

In the U.S. there is no such ruling, which means that cereals imported from there may still bring banned POEA into European food supplies. Monsanto’s website stresses that ‘Tallow amine-based products do not pose an imminent risk for human health when used according to instructions’.

In Europe, Monsanto has replaced POEA with a patented blend of two adjuvants — alkylpolyglycoside and nitroryl. A 2015 study in the journal Food and Chemical Toxicology could find no research data on the safety or otherwise of nitroryl.

Dr Antoniou fears that the effects of Roundup are cumulative, taking years of exposure to cause damage — a timescale that extends far beyond most studies’ scope.

‘The rats we studied were given an incredibly low concentration of Roundup, 10,000 times below what the EU regulations say is safe to consume on a regular basis,’ he says. ‘The rats showed this damage after two years’ exposure. Long-term exposure over decades could cause life-reducing harm.

‘Glyphosate-based herbicides could be contributing to chronic illnesses over a long range of time,’ he adds. ‘Regulators are only slowly waking up to this.’

Dr Antoniou is scathing about the manner in which regulators assess herbicide risk. ‘They tend only to look at what evidence the industry puts before them,’ he says, and claims: ‘Studies by independent scientists which show evidence of harm are on the whole ignored.’

MORE EVIDENCE IS NEEDED

Christopher Exley, a professor in bioinorganic chemistry at Keele University and an expert in eco-toxicology, sees it differently.

‘I think that the current “truth” is that there have not been the experiments to fully test the toxicity of glyphosate in humans,’ he says.

European Union legislators are treading a wary line on Roundup and similar glyphosate-based weedkillers. While individual countries have imposed bans, last year EU legislators voted to reauthorise the substance but agreed only to extend its licence for five years, far short of the 15 years sought. This was a last-minute compromise after weeks of wrangling.

On one side of the argument, 1.3 million EU citizens had signed petitions demanding a ban. On the other, farmers were threatening to revolt if glyphosate were not approved.

The UK government says it supports the continuing European Union approval of glyphosate. A spokesman for the Department for Environment, Food & Rural Affairs said: ‘UK scientists have advised it meets our high standards, both for health and the environment, while the European Food Safety Authority, the European Chemicals Agency Committee for Risk Assessment and the Joint Food and Agriculture Organisation/WHO Meeting on Pesticides Residues have concluded that glyphosate is not likely to cause harm to people.’

Mark Buckingham, Monsanto’s head of corporate affairs for the UK, describes the EU decision as ‘a reflection of a powerful political campaign against the product, rather than scientific doubt about its safety’.

As for the IARC’s classification of the chemical as a ‘probable carcinogen’, he says: ‘Their position is not supported by evidence. They relied on only four studies, some from the early Nineties, that have been reviewed by many other cancer-safety regulatory agencies. Only the IARC concluded that there is a risk of cancer — the opposite of all the other reviews. That isn’t credible.

‘We will defend these lawsuits with robust evidence that proves there is no connection between glyphosate and cancer. More than 800 studies back this. We have sympathy for anyone suffering from cancer, but the science clearly shows that glyphosate was not the cause.’

As for the current legal cases, even Dr Antoniou acknowledges that it will be very difficult for anyone individually to prove beyond doubt that Roundup is to blame for their illness. ‘Everyone exposed to large amounts of glyphosate will have been exposed to many other things that carry a cancer risk,’ he says. ‘I think they are going to struggle to definitively show that glyphosate caused their condition.’

Meanwhile, amid the legal dust-ups, Monsanto is about to perform a vanishing act. The German drug giant Bayer bought the company in June and says it plans to ‘retire’ the Monsanto name. The controversy over its glyphosate weedkiller, however, is unlikely to disappear so easily.