The study found that mercury, the toxic heavy metal used in gold processing, is silently poisoning water, soils and the environment.
Water samples near gold mining hotspots showed mercury levels of up to 100 times higher than the safety threshold for drinking water.
Eunice Atieno extracts gold at Osiri-Matanda mine in Nyatike, Migori /FILE
Artisanal and small-scale gold miners in Migori County are directly exposed to mercury-related occupational and safety risks, a new study shows.
A study by the Friedrich Naumann Foundation for Freedom – Kenya published in April 2025, found that Mercury concentrations are far beyond safe limits.
The study found that mercury, the toxic heavy metal used in gold processing, is silently poisoning water, soils and the environment.
Water samples near gold mining hotspots showed mercury levels of up to 100 times higher than the safety threshold for drinking water prescribed by the World Health Organisation and Kenya’s National Environment Management Authority.
Soil and waste samples (tailings) from mining areas revealed mercury levels two to three times higher than what is considered safe for farming, raising concerns that this toxic metal could seep into the local food chain.
Water samples from rivers like Nyangoto taken from river points just six kilometres from mining sites, revealed mercury levels more than 30 times the safe limit. The fish, for now, showed no detectable traces of the toxin.
The study relied on samples of water, soil, fish and tailings (mining debris) near mining sites collected during field visits in October 2024.
Migori is home to some 258,000 artisanal and small-scale gold miners. Gold mining supports livelihoods of an estimated 40 per cent of the population in Migori county.
“One big issue we found is the huge lack of data. The number of people working in mining in Migori is just an estimate, and there’s no proper information about the health problems caused by mercury exposure,” said Stefan Schott, the project director of FNF-Kenya.
“To really understand how serious this problem is, we need more data and ongoing monitoring. What we’re seeing might be a tip of the iceberg,” Schott said.
The study also established that gold mining is taking a socio-economic toll, with school-going children dropping out to engage in gold mining, affecting education in the county.
It also established a gender pay gap between men and women involved in gold mining, raising questions about gender discrimination.
Men dig for the ore deep in the shafts; the women process it – break stones, wash, and extract the gold. Yet the women are paid less, are sexually harassed, and have no voice. Both jobs are necessary to get the gold, so there’s no real reason for women to be paid less, according to the study.
The study recommended urgent regulatory and policy action to address health and environmental risks and the community to avoid water sources near mining areas to address mercury contamination crisis in Migori.
"Mercury exposure in the mining industry is a major public health threat that cannot be ignored — aggravating the portrait of what I call the ‘Vicious 9Ds of Mining’ — community displacement, disputes, dispossession, deprivation, destitution, disease, degradation, deformity and death," said Nashon Adero, author and expert in mining surveys.
Odero said mining done right is a significant source of inclusive economic empowerment.
He said it was urgent and critical for both local and national authorities to take immediate action to safeguard the health of mining communities and the broader ecosystem.
The study calls for implementing more equitable policies to address the exposed gender inequalities and ensure women have access to fair wages, decision-making roles and opportunities for economic empowerment.
It says sustainable mining practices, stronger regulatory enforcement and compliance monitoring and community education are essential to reduce the harmful effects of mercury contamination in Migori County and beyond.
This comprehensive field study, conducted from October 11 to October 30, 2024, involved community sensitisation, surveys and interviews with artisanal miners and other key stakeholders in the mining sector.
The research aimed to provide an in-depth understanding of the socio-economic, health, and environmental challenges mining communities face in Migori County.
The study also sought to identify sustainable practices that could reduce the mining sector’s harmful ecological footprint.
