For three weeks, heavy flooding wreaked havoc on John’s farm in North Yorkshire. To save his lambs from drowning, the farmer moved his flock to higher ground. Once the water receded, the animals were returned to their field.
Within three days, nine were dead. A post mortem attributed the deaths to lead poisoning.
Both the vet and toxicologist concluded lead sediment from a nearby abandoned mine, in UK Prime Minister Rishi Sunak’s constituency of Richmond, had contaminated the field after being carried downstream during the flood.
“We know the lead is now there, so we know how to manage it by rotating the animals around the fields to reduce exposure — but only through disaster,” says John, who breeds his lambs for slaughter. “No one is checking these things.” Like all the farmers interviewed, he asked to remain anonymous amid fears over his livelihood.
In total, there are an estimated 8,500 old metal mines across the UK that continue to disperse toxic metals including lead into the environment every year. Richmond, with its vista of rolling hills and historic market towns, is alone home to almost 2,500 abandoned lead mines — more than double any other UK constituency.
The often invisible and odourless poison accumulates in waterways, soil and floodplains where it can be consumed by animals or seep silently into homegrown or agricultural food production and then be passed on to humans.
This harmful legacy of Britain’s industrial past joins a range of pressing environmental issues the next UK government must grapple with, including raw sewage discharged into rivers and coastal areas and air pollution in urban areas. But experts warn that metal contamination poses risks to human health that are just as serious, yet receive comparatively little public attention.
Lead has a devastating impact on almost every organ in the body. Any level of exposure can have a harmful effect on humans, according to the World Health Organization.
In adults, exposure to the toxic metal is known to increase the risk of miscarriage, premature births, depression, chronic kidney disease and heart attacks. Children are more vulnerable and at risk of life-long reductions in IQ as well as behavioural problems.
While these long-standing concerns have led to a global ban on lead in petrol and paint, experts around the world continue to highlight risks of its presence in the food chain.
Yet for decades, academics commissioned on behalf of successive UK governments to study this issue say their warnings and calls for tougher action have either been ignored or buried. Climate change, which leads to more intense and frequent flooding, is compounding their fears.
In September 2023, Professor Mark Macklin from the University of Lincoln, who has been studying mine pollution for more than 40 years, published a global study that estimated as many as 557,000 people in the UK currently live on a floodplain contaminated by historic metal mining. The highest concentration was found in the northern Pennines, Cumbria, Cornwall, the Peak District, North Wales and the Yorkshire Dales.
“As one of the first industrial nations, there was no waste control or regulation [in the UK] when these mines were shut down,” says Macklin. “Poisonous metals were effectively dumped in the rivers and the sediment associated doesn’t disappear — it remains in the environment for thousands of years.
“I really do worry there could be a major human health incident in the future if we don’t get a grip on this,” he adds.
The threat of lead contamination in the UK environment has been understood for at least two decades.
In 2003, a study commissioned by the Department for Environment, Food and Rural Affairs (Defra) warned, “Many river floodplains in the UK have become contaminated by metal-rich waste in concentrations that may pose a hazard to ecosystem and human health.” Predicted increases in flooding should make research and development on this topic “a high priority”, it concluded.
In 2008, a report commissioned by the Environment Agency warned that people in England and Wales “may also be at risk from sediment-borne mining contamination”. The report called for detailed risk assessments to be carried out, contaminant monitoring and, if appropriate, remediation programmes.
But responsibility for dealing with the problem is spread between a range of bodies. Legislation to hold the owners and operators of mines responsible for the remediation of disused mines was not introduced until 1999, so the UK government inherited the liability when the majority of sites closed.
The Water and Abandoned Metal Mines (WAMM) programme — a partnership between the Environment Agency, the Coal Authority and Defra — was formed to clean up the pollution in England.
But it currently operates only four mine water treatment schemes to address pollution of rivers by abandoned metal mines, government officials say. There are also more than 20 diffuse interventions that limit metals being washed out of mines.
In January 2023, the UK parliament approved a new legally binding target to halve the length of rivers polluted by abandoned metal mines by 2038. But Macklin notes that current remediation efforts only target mine sites and not floodplains downstream. “It’s very unlikely indeed that this target will be met,” he says.
While government bodies have overall responsibility for environmental water pollution, it is local authorities who must identify contaminated land that could pose a risk to human health. However, councils are facing considerable financial pressures and have limited resources.
In 2010, after the European Food Safety Authority flagged “potential concern over possible neurodevelopmental effects in young children” because of lead exposure, the European Commission urged member states — then including the UK — to gather evidence on lead intoxication among farm animals in their respective countries.
Professor Toby Knowles from the University of Bristol, who led the UK’s research, studied lead levels in 112 farm animals across the country on land in areas with high geochemical lead. What he and his team found was troubling: lead levels in the samples of livers and kidneys in British sheep were “mostly above” the maximum limit at the time of 0.5 mg/kg, as were kidneys from cattle, according to findings published in 2014.
But in the introduction to the report on the UK’s Food Standards Agency website, the government body said: “The levels are not considered to be a risk to consumers.”
Knowles, now retired, questions the FSA’s choice of language. At no point does his report state that there was no risk to the public.
In response, government officials say offal — products such as kidney, liver or tripe — does not make up a large part of the average Briton’s diet, which is why the FSA stated that it does not pose a general risk.
They added that a leaflet was made available to farmers, which included guidance on how to mitigate the impact of contaminated land on livestock, such as fencing off areas of exposed soil. If such measures are not undertaken, they recommend offal should not enter the food chain.
However, the officials were unable to provide any data on the number of farmers declaring that their animals had been reared on land with high lead content, therefore ensuring their animal’s offal was destroyed.
Knowles remains concerned at the lack of protections put in place since his study more than a decade ago.
“Farmers should be declaring to abattoirs that their animals have been grazed on contaminated land on their food information sheets and that the offal should be discarded,” he says. “But how are farmers meant to know their land is contaminated if no one is testing?”
It’s not only an issue for farmers, he adds. “The Food Standards Agency should [also] be really worried about local people growing their own crops, not washing their own vegetables and eating domestically produced eggs.”
Some level of food testing for lead does take place. Every year, the UK’s Veterinary Medicines Directorate tests around 33,000 samples of meat, milk, fish, eggs and honey.
Of these, 400-450 samples are specifically tested for the presence of lead and other heavy metals, with the exception of eggs, for which no lead level is set in the UK.
But the size makes for an insufficient risk assessment, says Knowles. “It gives you no idea how big a problem it is.”
It comes as little surprise then that over the past 10 years, only 40 incidents of non-compliant lead levels have been reported and investigated, he says.
As recently as 2022, UK government vets detected lead levels in the kidney of a sheep sampled from a large farm affiliated with Red Tractor, an assurance scheme that promotes high food standards. At 0.56 mg/kg, the levels were nearly three times the threshold of 0.2 mg/kg. An investigation found the farm, which was rearing over 3,000 breeding ewes, lambs and cattle, was located “close to several lead mines located in the area”.
Five years earlier, a farm in the same area had one cow in a serious condition through lead poisoning. The farmer was handed an “information leaflet on lead poisoning” and “advised to voluntarily test the soil and water for lead content”, the report found.
Officials say food cannot be kept completely free of lead. Instead, the aim is to reduce concentrations to as low as is reasonably achievable.
The Joint Food and Agriculture Organization and WHO Expert Committee on Food Additives says it is “not possible to set a tolerable lead intake”. However, there are regulatory maximum limits for lead in a wide range of foods in the UK, based on measures introduced by the EU Commission in 2015.
However, when the EU extended the list of foodstuffs covered and lowered the maximum permitted lead content in some of them, the UK did not follow suit, the FSA confirms. Officials say the government will review levels of lead in all foods in due course and consider any changes based on what is achievable.
Some farmers feel the government is not taking the issue seriously enough.
When Alan’s sheep started to miscarry and his ewes were not growing as they should about a decade ago, the North Yorkshire farmer called his local vet.
Blood tests in the animals showed elevated lead levels, prompting the vet to recommend a soil analysis. The UK has no statutory maximum level for lead concentration in soil, but in the US the acceptable threshold is 200 parts per million. On Alan’s farm, lead levels in the soil were at 2,129ppm.
“They banned lead paint and petrol but they don’t seem to be doing much when it comes to lead getting into foodstuffs,” says Alan. “I think the government is trying to keep it under the radar.”
However, concerns over the threat of lead contamination are now gathering momentum.
Earlier this year, a UK parliamentary committee launched an inquiry into the human health risks posed by abandoned metal mines in Wales following an FT investigation.
The decision came a year after a study funded by the Welsh government uncovered harmful levels of lead in eggs produced on two small farms downstream from abandoned lead mines in west Wales.
A young child eating one or two of the eggs per day “could become cognitively impaired”, it warned. The academics behind the study say they fear these eggs continue to be sold at local markets.
The Welsh government is now facing “urgent” calls from the House of Commons’ Welsh affairs select committee to take action to avoid a potential “environmental and public health scandal”. MPs want the devolved government to consider amending the remit of Natural Resources Wales, a government-sponsored body, to include the effective remediation of land contaminated by metal mine pollution. As well as implementing clear targets for remediation, the committee calls for the creation of a database of local authority action on contaminated land.
Following the 2012 floods in Mid Wales, after which several cattle died, a team of academics carried out an investigation which found flood sediments were contaminated above pollution guideline thresholds.
Most significantly, they found the silage, or fodder, produced from flood-affected fields contained levels of lead concentration that caused “cattle poisoning and mortality”.
In language that goes significantly beyond the Food Standards Agency conclusion, the report warned of the “potential health implications for humans if meat from poisoned animals finds its way into the food chain”. It added: “Furthermore, it is highly likely that acute animal ill health (and mortality), as a result of (lead) poisoning, is far more widespread in the UK than hitherto realised.”
Lincoln university’s Macklin, who has worked on a series of reports commissioned by government departments and agencies into the health risks of disused mines, believes the situation in Wales is the “tip of the iceberg” facing the UK. England has more than 6,000 abandoned metal mines, around 3,900 of which are old lead mines.
The full extent of the risks are still little understood. Two years ago, Luke left London for rural Wales. After moving into his remote farmhouse, a chance conversation with a neighbour about the prevalence of old lead mines in the area prompted him to test his drinking water.
The results were devastating. Testing carried out in September by a private company showed his drinking water was more than 10 times over the legally permitted 10 mg per litre. Within four hours of notifying his GP, Luke was having his blood, liver and kidney tested.
His local council also carried out extensive tests on the property, initially assuming the lead levels in the drinking water were down to old piping. “But the expert who came here said it wasn’t the pipes but the ‘environmental lead’ in the area,” he says.
Despite drinking the water from his property’s private bog for two years, his own lead levels were not toxic. “I feel like I really dodged a bullet”, Luke says. “The real issue is that you can be taking in really high doses for years and not know because the symptoms aren’t always obvious,” he adds. “I could have been poisoning myself for years.”
Cartography by Steven Bernard