Informal lead mining in Nigeria is exposing entire communities to dangerously high levels of airborne lead — in some cases, up to ten times greater than the permissible exposure limit set by US health authorities, a new study has revealed.
Published in the Journal of Occupational and Environmental Hygiene, the study is the first of its kind to directly assess airborne lead exposure from self-employed artisanal miners in Nigeria. These small-scale, often illegal operations use rudimentary tools and lack environmental or safety oversight, yet they are increasingly fuelling a booming lead export market.
Much of Nigeria’s lead ore is exported to China for battery production, with demand surging in recent years. Between 2013 and 2022, lead shipments from Nigeria reportedly soared by 360%. Similar trends and risks have also been observed in countries such as Zambia and Myanmar, where unregulated mining has been linked to widespread contamination.
The researchers also examined artisanal gold ore processing in northern Nigeria, where miners frequently use manual or diesel-powered tools to crush rock. This process often releases large quantities of lead dust into the air, resulting in exposure levels that in some instances exceeded occupational safety limits by more than 30 times.
Manti Michael Nota, a lecturer at Ardhi University in Tanzania and lead author of the study, said: “We found that lead exposures among underground lead miners are as much as 22 times the occupational lead air standard. These exposures are contributing to the high rates of childhood lead poisoning we have seen in these communities.”
Perry Gottesfeld, Executive Director of Occupational Knowledge International (OK International), which co-authored the study, said the findings highlight the severe health threats posed by under-regulated mining.
“These findings suggest that informal lead mining is one of the most hazardous forms of mining that gets little attention despite the growing presence of self-employed lead mining operations around the world,” he said.
Lead exposure is known to cause neurological damage, developmental issues in children, and cardiovascular disease. It is estimated to contribute to around five million deaths annually. In 2020, Nigeria’s Zamfara State experienced a devastating outbreak of lead poisoning linked to artisanal gold mining, with hundreds of children killed and thousands more suffering long-term health effects due to exceptionally high lead levels in the ore.
