Editor’s note: Mining poisons the earth, not only right now, but for future generations: even if the mine is closed and all workers have left, the chemicals and metals that they have used and mined will stay hidden in the soil. But it can’t be hidden forever. When the earth moves due to flooding so do the chemicals. They then poison the land and water and damage the ecosystems.

Uganda’s Nyamwamba river, in the Rwenzori Mountains, has begun to flood catastrophically in recent years, partly due to climate change. Along the river are copper tailings pools from an old Canadian mining operation, which are becoming increasingly eroded by the flooding. According to a series of studies, these tailings have been washing into the water supply and soil of the Nyamwamba River Basin, contaminating human tissue, food and water with deadly heavy metals. Cancer rates are higher than normal near the tailings pools, and scientists fear that as the flooding continues to worsen, so will the health crisis.

By Terna Gyuse/Mongabay

KASESE, Uganda — Right as the Nyamwamba River emerges from the foothills of western Uganda’s Rwenzori Mountains and begins its final descent onto the savanna, it passes by a curious sight. On the far bank from the road, past piles of sun-bleached stones on the now-dry riverbed, the earth has been disturbed. Towering walls stand naked and exposed amid the surrounding hills, as if a mighty hand has taken a scoop from the very landscape itself. Sheer cliffs emerge abruptly from the green scrub above, crashing downward into a flat, brownish pit of sand and rocks.

This is a copper tailings pool. Along with its siblings, it’s poisoning this part of Uganda.

The pools were built to hold waste from a mine once operated by Falconbridge, a Canadian company that ruled over the Rwenzori foothills from the 1950s to late ’70s. In its heyday, Falconbridge’s copper mine, based just up the road in the small town of Kilembe, was the churning engine of Uganda’s economy. The mine once employed more than 6,000 people and accounted for nearly a third of the country’s GDP.

Falconbridge was chased out of Uganda by Idi Amin in 1977, who nationalized the mine in the final years of his rule, convinced that his government could run it as well as the Canadians and keep more of the copper’s value at home. By 1982, it was shuttered.

In Kilembe, Falconbridge’s ghostly remains are ubiquitous. Decaying company housing is still occupied by former employees and their descendants. Rickety mining infrastructure dots the hillside. The tailings pools stand as monuments to what was once taken from here and sent northward to feed the booming engines of Western capitalism’s golden age.

A toxic legacy is now seeping from these pools and into water, soil and bodies in this region, as the Nyamwamba bursts its banks with flooding increasing frequency. Global warming has disturbed the climate above the mountains on high — during the rainy season, floods have become more common. As the Nyamwamba’s floodwaters rage past the tailings pools like this one every year, toxic heavy metals are being washed downriver toward the district capital of Kasese and its 100,000 residents.

In Kilembe, the toll is already evident. Cancer rates have skyrocketed. Spurred along by the burning of fossil fuels in faraway locales, the wounds of extraction in this area have begun to fester and become gangrenous.

“When we were starting our study in the Kilembe mine area, [this] whole tailing dump was not touched by water,” said Abraham Mwesigye, an environmental scientist at Kampala’s Makerere University. “But because of over flooding, we’ve lost tons and tons of tailing waste into River Nyamwamba … and that has only happened in the last four years when the effects of climate change increased in the Rwenzori Mountains.”

Pools of menace

In all, there are 15 million metric tons of copper tailings in the area around Kilembe. A decade ago, Mwesigye and his colleagues began to investigate their impact on health and the environment. In the period since, study after study have shown startling results.

Copper, cobalt, arsenic, nickel, zinc and lead is everywhere. There’s nickel in the cassava and beans grown along the Nyamwamba’s banks. Copper concentrations are several times higher than average in people’s toenails. In more than half of the samples taken of drinking water near Kilembe and downstream in 2017, there were unsafe levels of cobalt. The soil is contaminated, dust found inside of people’s homes is toxic, and even the grasses that livestock and wild animals graze on show elevated traces of heavy metals.

The concentrations are particularly high, often dangerously so, near Kilembe. But they can also be found further downriver, near the more populous town of Kasese.

“Over times these wastes have been eroded into farms and the River Nyamwamba, which is a main water source for locals,” Mwesigye said in a phone interview with Mongabay. “The danger is that they contain heavy metals, including those which are very toxic. We’re looking at copper, cobalt, zinc, arsenic, manganese and iron. We tested and found more than 42 elements in those wastes, and they are ending up in drinking water supplies and agriculture.”

Some of the elements washing into the Nyamwamba are carcinogenic. Cobalt, for example, was recently escalated by the European Commission as a Class 1B risk, meaning excessive exposure to it is almost certain to cause cancer. Samples of yams grown near Kilembe in 2019 showed levels of cobalt that exceeded the safe limit for children in particular.


“Cobalt is the second most abundant contaminant within Kilembe after copper,” Mwesigye said.

These toxins are causing a silent but growing health crisis in Kilembe, he added.

“We surveyed the Kilembe hospitals and health facilities, and we found that there are high rates of cancer and gastrointestinal diseases, both of which are associated with exposure.”

There have been no definitive studies linking the prevalence of heavy metals in Kilembe and Kasese with elevated cancer rates — yet. But media reports suggest these rates are higher than average compared with other parts of Uganda. Municipal officials in Kasese say they suspect the tailing pools are to blame, with toxins showing up in the produce people eat.

“We are afraid that the increase in cancer in the area might partly be caused by the water [used to grow food],” said Chance Kahindo, Kasese’s mayor.

Mwesigye’s findings have been backed up by other researchers. In a 2020 study published in the Octa Journal of Environmental Research, samples taken from the Nyamwamba near Kilembe were shown to have levels of copper and cobalt that exceeded safe limits set by the World Health Organization. Tissue samples taken from the river’s fish, a crucial source of local food, were also recorded as having accumulated unsafe amounts of cobalt, lead and zinc.

Environmental advocates say it’s almost certain that the metals are also affecting wildlife in Queen Elizabeth National Park, a sprawling nature reserve that the Nyamwamba cuts through on its way into Lake George. A UNESCO World Heritage Site, the park is home to lions, buffalo, leopards, hippos and African savanna elephants.

“These copper tailings end up journeying into the water,” said Edwin Mumbere, director of a Kasese-based environmental group. “So there’s heavy metal pollution that isn’t only affecting us as a community, it’s affecting animals [in the park].”

As far back as 2003, a study showed higher-than-normal concentrations of copper and zinc in Lake George, about 30 kilometers (19 miles) downstream of Kilembe, including in the fish that feed tens of thousands of people in the region. The levels detected in their flesh were considered safe for human consumption — but that was before the Nyamwamba’s floods started getting worse and more frequent.

In 2022, a researcher with the Uganda Cancer Institute told a journalist that cancer cases from Kasese “seem to be increasing,” but the link between health problems in the region and the prevalence of heavy metals hasn’t been thoroughly studied. According to unpublished data shared with Mongabay by the Kampala-based Uganda Cancer Institute, a recent study did not show higher-than-average rates of cancer in Kasese district as a whole. But the figures covered the district’s full 800,000-strong population, and hadn’t been disaggregated to evaluate rates among those living in the city of Kasese or other settlements between Kilembe and Lake George.

“Foods that are grown in Kilembe are sold all over Kasese town,” Mwesigye said. “So there’s a likelihood that residents of Kasese are consuming contaminated foods … and when there’s flooding, you’ll find the tailings there, because the River Nyamwamba busts its banks and spreads waste all over.”

For people in the region who do contract cancer, wherever it comes from, a painful ordeal often awaits. If they don’t have the money to pay for treatment in one of Kampala’s specialized private wards, there’s little they can do besides wait for the disease to consume them. Media reports speak of stricken patients slowly dying at home without receiving proper care.

Old scars reopened by new wounds

The toxins coursing through the life systems of Kilembe have produced a catastrophe that’s both urgent and, at least for now, part of the fabric of life. There’s no choice: even as the waters rise and the poisons soak deeper into it every year, people who call the Nyamwamba’s banks home must adjust. It isn’t a unique situation. As ecologies change and the bill for the 20th century comes due, people closest to that debt often don’t have any option other than to try and work around it.

Across the African continent, as well as in other places whose forests and mines fed the engine of global growth, there are wounds, infected and seeping even when the hands that opened them are long gone.

“We’re still in the extractive phase in countries in Latin America and Africa, but the problem will be in a century when they will have the legacies,” said Flaviano Bianchini, director of Source International, an NGO that campaigns on behalf of mining-affected communities. “The cost of cleaning the pollution caused by a mine is huge, enormous. Millions and millions and millions [of dollars].”

In Africa, these legacies are already festering. In Uganda’s neighbor, the Democratic Republic of Congo, a copper mine owned by the Swiss multinational Glencore in Lualaba province has rendered farmland unusable and poisoned local waterways. In 2022, the company agreed to pay $180 million to the country after admitting that it spent more than a decade bribing senior officials there.

Further south, in Zambia, children born in the town of Kabwe, which hosted a lead mine operated by the British giant Anglo-American between 1925 and 1974, can have blood lead levels as high as 20 times the safe limit. Kilembe isn’t an outlier — it’s the norm.

Some public interest lawyers are trying to turn the tide and hold companies accountable. But they face an uphill battle. In December, a South African court threw out a case that the U.K.-based firm Leigh Day brought against Anglo-American over the damage it left behind in Kabwe.

The court said that by trying to force Anglo-American to pay for the mess, the plaintiffs wanted to “advance an untenable claim that would set a grave precedent.”

While Leigh Day is currently working towards appealing the ruling, it symbolized the difficulties that communities face in African courts when they take on mining giants or governments. Impunity has taken a toll.

“When it comes to the harm that has been suffered by workers and communities, the lack of access to justice locally has meant a lack of deterrence and an insufficient incentive on companies to behave better,” said Richard Meeran, the lead attorney from Leigh Day on the Kabwe case.

When companies pack up and leave, whether because a mine has been depleted, the operation has become financially unviable, or over a dispute with the government, it’s the people who live nearby — those with the least resources — who are left holding with the bill.

“Legal systems must evolve to hold companies accountable,” Marcos Orellana, the U.N. special rapporteur on toxics and human rights, said in an email to Mongabay. “And courts must be open and willing to hold past polluters accountable for the harm they have caused to communities and the environment.”

It won’t do much good for anyone living in Kilembe or Kasese to knock on Falconbridge’s door. In 2006, it was acquired by the Swiss-Anglo firm Xstrata, in a $22.5 billion deal that was one of the biggest in Canadian history at the time. A few years later, Xstrata was taken over by Glencore, the world’s largest commodities trader. According to company data, in 2022 Glencore posted a record profit of $17.3 billion, paying more than $7 billion to its shareholders.

In an email to Mongabay, Glencore declined to comment on Falconbridge’s legacy in Uganda.

Despite its noxious aftermath, Ugandan President Yoweri Museveni has spent the better part of a decade trying to restart copper mining in Kilembe. After an embarrassing episode in which a Chinese company took control of the mine only to lose its contract due to inactivity and unpaid fees, the Ugandan government has found new suitors. Late last year, Kilembe hosted a delegation to showcase the infrastructure Falconbridge left behind. Media reports suggest a new deal may be approaching.

If a new owner is found, it’s unclear what, if anything, they will do about the tailings pools and their grim legacy.

In the meantime, the people who live along the Nyamwamba River are caught between two ecological crises at once, separate yet linked. From above, a warming atmosphere robs them of the sacred sites and steals their homes in rushing flooding waters. At the same time, poisons from the scarred earth seep deeper into their food, water and bodies. From both directions the consequences of extraction, and in neither any relief in sight.

That environmental wounds from a fast-approaching future are dovetailing with those of western Uganda’s unresolved past carries an ominous message. The climate crisis is not set to arrive on its own. It will have company.

Photo by Darilon/pixabay, reinout_dujardin1/pixabay