THE use of mercury in small-scale and artisanal gold mining is inevitable with the coming into force of newer mechanisms to help protect the environment and stop mercury’s entry into the food chain.
Mercury is used in extracting gold and silver from ore and refining of other metals including gold, silver and zinc although most of this can be captured and reused.
A tonne of ore may contain less than an ounce (30g) of gold
This process has since been replaced by more efficient and less environmentally damaging techniques such as cyanide leaching in large-scale and industrial mining.
However, in developing nations including Zimbabwe, mercury pollution is increasingly a result of illegal or artisanal mining and is an ongoing and growing concern.
Mercury is highly toxic and can cause serious illness and death in humans and animals.
It is a neuro-toxin and affects the cerebellum, which is the part of the brain that helps one move properly, and co-ordinate movements. Mercury also harms the kidneys and other organs, and the neurological damage it does is irreversible.
As a result, efforts are being made to reduce the use and release of mercury for health and environmental reasons globally.
The Minamata Convention signed in Japan which many countries are party to is a global legally binding instrument on the use of mercury and Zimbabwe is yet to ratify it.
The convention looks at the supply sources and trade of mercury, the reduction and elimination of its use in gold mining, emissions into the environment and many other things.
It was necessitated by the symptoms which appeared only gradually in the fishing village of Minamata.
At first, nobody could explain why people began to slur their speech or stumbled when they walked, had trouble while swallowing, or trembled uncontrollably.
Children were born with disabilities.
Thousands would die with what became known as Minamata disease.
But it took 30 years – until the 1960s – to identify the cause of the suffering: a local plastics factory that was dumping mercury into the bay.
The mercury was contaminating fish, the staple food of the local population.
Mercury also known as ‘quicksilver’ is an element found in nature in various forms.
It is released into the environment through natural processes such as volcanic eruptions, the weathering of rocks, and forest fires. Mercury is also released through human activities and industrial processes.
Humans have mined mercury since the Roman times and mercury is still used in products such as fluorescent lights, energy saving lamps, and electronic devices.
There are an estimated 10-15 million unregulated gold miners around the world, operating in 70 countries.
Artisanal small-scale gold mining (ASGM) is the largest source of mercury pollution in the world after the burning of fossil fuels.
Mercury is an element which does not break down in the environment. Instead, it is cycled between the atmosphere, land, and water, and can travel large distances from the original source.
Mercury can also build up in humans and animals and become highly concentrated in the food chain. Low levels of mercury exposure can build up over time until concentrations are high enough to be harmful.
The United Nations Industrial Development Organisation estimates that 1 000 tonnes of mercury is released into the air, soil, and water each year by this sector.
According to the president of Women in Mining, Mthandazo Muhau, the small-scale and artisanal miners who use mercury to purify gold from ore inhale toxic mercury vapours through this process.
“The process called amalgamation often results in miners and their families inhaling toxic mercury vapors through this process,” said Muhau.
“Some of them because they are not monitored can also contaminate the land and water where gold processing occurs.
“More training needs to be done on how to properly use mercury during that process.”
World Bank representative Rafik Hirji said, “mercury causes diseases which are long term in nature unlike cyanide.
“It stays in the system and accumulates.
“We estimated in 2010 that at least 161 000 tonnes of mercury is used annually and 1 600 of that is used by artisanal and small-scale miners.
“A lot of this mercury is imported illegally and the control of importation very hard.”
A Global Mercury Study by UNIDO done in 2007 in Chakari, Kadoma, which is one of the hot spots of mercury pollution, indicated traces of mercury intoxication. The health survey results showed that 49 percent of men, three percent of women and 15 percent of children were mercury intoxicated.
Forty-six pairs of breast milk had traces of mercury in it.
Twenty-two out of 46 children had higher traces of mercury intoxication.
A new rapid study being done by the Environmental Management Agency (EMA), the World Bank and a consultant is set to review information that is already known about the impacts of mercury in the hot spots of the country.
What is already known is that there are over 1, 5 million miners in Zimbabwe who use over 25 tonnes of mercury to produce over 60 tonnes of gold per annum. Zimbabwe produced more than 14 tonnes of gold last year and over three million people depend directly or indirectly on gold mining.
For the above reasons, there is need for various stakeholders to come together to help reduce the negative impacts of mercury on people.
According to an official from the Mines and Mining Development Ministry, Statutory Instrument 329, SI 63 of 2005 and SI 63 of 2007 of the Mining policy while they deal with artisanal miners do not deal much with mercury because they have no alternatives yet.
He recommended the harmonisation of the environmental and mining laws.
Global initiatives such as the UN-led Global Mercury Project are trying to help miners in developing countries adopt best practices and reduce mining pollution caused by the use of mercury.
Mercury Watch an organisation ‘dedicated to collecting, analysing, and publicly serving information about mercury released to the environment’, claims that “artisanal scale gold mining has the single largest demand for mercury in the world. “An estimated 1 400 tonnes of mercury were used by artisanal scale gold mining miners globally in 2011.”
Subsistence artisanal small-scale gold mining is a way to survive for an estimated 10-15 million miners in 70 countries, including approximately three million women and children.
Surprisingly and on top of being the world’s largest employer in gold mining and representing 90 percent of the gold mining workforce worldwide, small-scale gold mining produces 15 percent of the annual gold production.