East Africa leads efforts to cut use of mercury in mining
Kenyan women wash the ore off the gold in a process that involves mixing it withmercury. PHOTO FILE | NATION
What you need to know:
East Africa is driving a global initiative to phase out the use of mercury in mining, as it is harmful to human health and the environment.
Mercury is used to recover gold pieces mixed in soil and sediments. Mercury and gold settle to form an amalgam, then the gold is extracted by vaporising the mercury through heating.
The Zero Mercury Working Group estimates that 15 million people in 70 countries employed in artisanal and small-scale gold mining are exposed to mercury.
East Africa is driving a global initiative to phase out the use of mercury in mining, as it is harmful to human health and the environment.
Kenya, Uganda, Tanzania, Ethiopia and Burundi have announced plans to phase out use of mercury in artisanal mining of gold, which tends to be poorly regulated due to the remote locations of the mines.
Mercury is used to recover gold pieces mixed in soil and sediments. Mercury and gold settle to form an amalgam, then the gold is extracted by vaporising the mercury through heating. The miners use rudimentary equipment — blowtorch or stoves at home. The miners inhale the vapour from the amalgamation, to the detriment of their health.
Cyanide, another dangerous substance, is used by small scale miners on tailings (waste ore) to extract more gold that combines with mercury to make compounds dispersed in water and taken up in food chains.
The Global Environment Facility said it is giving Kenya $45 million with a co-financing of $135 million from private firms, governments and financing institutions, to eliminate mercury.
United Nations Development Programme said the GEF gold project will promote best practices and techniques to reduce mercury releases by 369 tonnes. Kenya expects $200 million from GEF. Burkina Faso, Colombia, Guyana, Indonesia, Peru, Mongolia and Philippines are the other beneficiaries of the programme.
Minamata disease
Fifty countries have ratified the Minamata Convention on Mercury, which enters into force on August 16, 2017. Kenya signed it in 2013.
It is named after the place in Japan, where thousands of people were poisoned by mercury-tainted industrial wastewater in the mid-20th century, leading to a crippling condition that became known as Minamata disease.
“From the tragedy in 1950s, the Unep Governing Council in 2009 developed a legally binding instrument on mercury, and it has been a long journey,” said GEF chief executive officer Naoko Ishii.
Ms Ishii said that, like other heavy metals, mercury persists in the environment; can be transported over distances the from original emission source; and contaminate food, water and air.
Mercury in mining is deemed wasteful, as it achieves only about 20 to 30 per cent efficiency in recovering gold, compared with 60-90 per cent from alternative, cleaner methods like borax, used by large-scale miners in Tanzania.
Borax, invented over 30 years ago in the Philippines, is used in Chunya and Singida districts in Tanzania.
The Zero Mercury Working Group estimates that 15 million people in 70 countries employed in artisanal and small-scale gold mining are exposed to mercury. Four to five million of them are women and children.
UNDP head of programme in Kenya David Maina said exposure to mercury, even in small amounts, may cause serious health problems, including affecting a foetus.
“Mercury can be passed from mother to foetus or breastfeeding baby. Exposure to mercury is high in children and teenagers,” he said.
UNDP supports Kenya’s efforts to phasing out mercury from early 2018 by strengthening institutions through technical assistance, technology transfer and awareness on the dangers of mercury.
Small-scale mining occurs in counties of Migori, Kisumu, Siaya, Vihiga, Kakamega, Pokot and Turkana.
