Study confirms contamination of people and wildlife from historic Welsh mines
A scientific review has confirmed that people, livestock and wildlife are being contaminated by toxic metals leaking from historic mines and smelting sites in Wales. Researchers established the issue is having "health consequences" but said more work was needed to quantify the impacts.
In a Department for Environment, Food and Rural Affairs-commissioned study, Nottingham University academics assessed 255 documents published between 1874 and 2025. All examined land that had been contaminated by former metal mines and smelters, as reported by both the Daily Post and South Wales Echo.
The publication of the Nottingham study coincided with the BBC's Buried documentary series presented by Michael Sheen.
Regional case studies
The research incorporated a study evaluating North Wales' historical lead and zinc mines and another looking at two housing estates in Flintshire, according to the Daily Post. Two former lead smelting works in the region were also assessed. Several of these sites were found to pose a "significant possibility of significant harm" to human health, mainly due to soil metal pollution, the newspaper reported. Others were said to need further study to determine the level of risk.
Natural Resources Wales estimates 1,300 abandoned metal mines in Wales, the Daily Post noted. Although most mining had ended by the 1920s, discharges of water from underground workings remain significant sources of water pollution, compounded by leaching or erosion of metals from spoil heaps. This has resulted in Wales being home to nine of the ten worst metal mine-polluted river catchments in the UK. NRW said: "Over 500 tonnes of metals like zinc, lead, cadmium and iron enter Welsh rivers from abandoned mines every year, causing 6% of them – nearly 700km – to fail to achieve good chemical or ecological status."
NRW said it is working with the Mining Remediation Authority to address the issue by capping mines, diverting streams and landscaping sites.
Environmental and health impacts
The study focused on nine key metals and metalloids associated with mining—arsenic, cadmium, copper, iron, lead, nickel, silver, tin, and zinc—and noted that while significant efforts have been made over the last 50 years to reduce human exposure to these metals, such as removing lead from petrol, environmental exposure through metal mining or smelting sites has not been addressed, the South Wales Echo reported.
According to the newspaper, the study found that metal contamination is common across former mining regions of the UK, particularly Wales and south-west and north-west England, and is reflected in body burdens in local wildlife, livestock, and humans. Negative health impacts have been detected in terrestrial and aquatic invertebrates, fish, rodents, livestock, and humans.
However, the South Wales Echo noted that no peer-reviewed studies on health impacts in mammalian livestock in England or Wales have been published in the last 70 years, and a comprehensive assessment of health risks and impacts is not possible with currently available information.
Climate change and future risks
Climate change is expected to spread metal contamination further through environments by mobilising mine wastes during extreme weather events and distributing them during flooding, the South Wales Echo reported. A key knowledge gap identified in the study is how animals in mine-affected areas will respond to future climate and land-use changes. Lead contamination is a particular concern, causing poisoning at higher concentrations and potential ill-health at lower levels.