Johannesburg sits atop the world’s most productive gold reef — a staggering 40,000 tons of the precious metal has been mined from it during a history tracing back 130 years. That legacy of riches has left behind a toxic inheritance: radioactivity from uranium hauled up in the mining process.
Scientists have found uranium quantities in rivers west of the city to be as much as 4,000 times natural levels and in tap water as much as 20 times higher. A soil sample taken by Bloomberg News and tested by government-certified WaterLab Ltd. from pumpkin roots grown a little more than a mile from a recently closed gold mine contained five times more uranium than background levels considered normal by the International Atomic Energy Agency.
Residents of Johannesburg and surrounding communities live among an estimated 600,000 metric tons of uranium buried in waste rock and covering an area four times the size of Manhattan, according to university researchers. Another undetermined amount lies below ground, where water has filled abandoned mines and leaks into the environment.
“There’s nowhere in the world where you’ll find so many people living alongside such a vast amount of ore-bearing uranium,” said Carl Albrecht, head of research at the Cancer Association of South Africa, or Cansa. “There are 400,000 people in the area who are subjected to this environment and yet the government is unwilling to consider the health impact.”
Government regulators and health advocates disagree over the public-health threat this poses. Albrecht and others point to U.S. Environmental Protection Agency data that says even low-level radiation exposure, if prolonged, can lead to an increased rate of cancers. Susan Shabangu, minister of South Africa’s Department of Mineral Resources, said levels recorded in and around Johannesburg are “a cause for concern” but not yet a “level of danger.”
One thing is indisputable: the amount of untreated waste material containing uranium is growing as a 28 percent plunge in the gold price last year has shuttered mines and increased the number of abandoned mine sites. The Blyvooruitzicht mine 50 miles (80 kilometers) southwest of Johannesburg — near where the Bloomberg News soil sample was taken — was closed in July, throwing 1,700 miners out of work.
The mine’s last operator, Village Main Reef Ltd., isn’t responsible for the environmental rehabilitation of the mine because it never took legal ownership of the operation, according to Chief Executive Officer Ferdi Dippenaar.
Village operated the 72-year-old mine for 18 months, he said.
“As far as I am aware, and based on tailings recoveries, the content of uranium during this time was definitely within limits,” Dippenaar said. Tailings refers to waste material. Village has no plans to reopen the mine and it’s currently being liquidated, he said.
Unmaintained, abandoned dumps lose their shape as their toxic material seeps into the surrounding area, said Anthony Turton, a professor at University of the Free State’s Center for Environmental Management. When waste dumps, known as tailings dams, are abandoned “you get major erosion taking place and slides of toxic material into wetlands,” he said.
While South Africa has required companies to set aside money for environmental mitigation since 1994, “the reality is the funds set aside for environmental liabilities are totally insufficient,” Turton said.
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