The dark side of gold: the dangerous effects of mercury used in artisanal gold mining

30 April 2020

Gold is a rare and precious metal, popularly used in jewellery, art, electronic devices, coins, and even in food. But where does gold come from, and does the price paid for gold reflect its full costs? This beautiful shiny metal has a dark side. Artisanal miners risk their lives extracting gold, using toxic chemicals such as mercury, and potentially endangering their environment and local communities. The DUPC2 funded project “Synoptic and participatory assessment of environmental pollution and health effects due to exposure to mercury from artisanal gold mining” is conducting an assessment on the dark side of artisanal gold mining in the Alto Cauca basin in Colombia. 

Gold rush

Some of the largest deposits of gold and other precious metals can be found in Latin America. Latin American countries are already experiencing considerable economic growth, harvesting these precious metals could increase their prosperity even more. Unfortunately, collecting these precious metals comes with a price, and carries both environmental and health risks for populations, especially through mining. 

Artisanal miners are independent, informal miners that use their own resources to extract precious metals or pan for gold. Although the practice is often illegal and unregulated, artisanal mining is an important source of income for poverty affected populations. Already working in precarious conditions, artisanal miners frequently use mercury to extract gold. The mercury used is released into the local environment, contaminating soil, water and the atmosphere, affecting not only local, but also distant populations that live further down the river or depend on the same ecosystems.

The impacts of mercury use

The DUPC2-funded project “Synoptic and participatory assessment of environmental pollution and health effects due to exposure to mercury from artisanal gold mining in the Alto Cauca basin, Colombia” is led by Universidad del Valle in Cali, Colombia. As the name suggests, the project aim is to determine the state of contamination and human exposure from artisanal gold mining, focusing on the Alto Cauca basin.

Inhaling mercury vapour is most dangerous, and those that manipulate the mercury directly in the process of gold extraction, especially by burning mercury, are therefore most at risk. Through the use of contaminated soil and water for livestock and crops, mercury can also enter the food chain. Communities near artisanal mining locations can therefore gradually accumulate mercury in their bodies, which is especially dangerous for pregnant women, children and the elderly.

Extended exposure to mercury can cause mercury poisoning, and can damage kidneys, impair hearing, vision, and balance. In extreme situations, it can cause people to become comatose or even claim lives. Often time those who are most vulnerable, young children and elderly, are those most prone to fall victim to the effects of mercury. The negative impact of mercury in artisanal mining in Colombia is well documented by the United Nations Industrial Development Organization Mercury Programme, yet the use of mercury remains persistent.  

Minority communities at risk

The Alto Cauca basin is rich, not only in its biodiversity, but also in its ethnic diversity of indigenous people, mestizo peasants and Afrodescendants. The project focuses on two Afrodescendent communities affected by mercury exposure through artisanal mining in the Alto Cauca basin: La Toma and Yolombo. Practiced for centuries by Afrodescendent miners, artisanal mining in recent years has seen a shift from using mechanical extraction (the use of iron picks and bare hands) to include the use of mercury to extract gold, exposing themselves and their community to the toxic chemical. The maximum mercury levels in water is 1 ppb-Hg+2, set by the WHO, yet previous laboratory analysis conducted by Universidad del Valle has shown a significantly higher level of 4 ppb-Hg+2 in the region.

The strong connection to their ancestral lands makes the communities reluctant to migrate to other areas. A lack of basic services, including water supply, and insufficient environmental protection related to gold mining and public health only increases the risk of mercury exposure. Women in the region are reporting an increasing number of cases of abnormalities in new born babies, impairments in vision in young children, and elderly experiencing uncontrollable shaking.

Changing behaviour

By conducting a thorough assessment of the situation, the project hopes to reveal the environmental conditions and dangerous health risks in the Alto Cauca basin as a result of mercury use. This study would serve as a basis for calling attention to environmental protection institutes.

Not only actions from environmental or governmental institutions are needed to change the situation for the better. Miners and local communities must also change their perception of the dangers of mercury use, and a change in behaviour is needed to decrease environmental and health danger for the long term. The knowledge acquired through the project will be transferred to local communities through educational campaigns, informing them of the dangers of mercury use, and hopefully changing community’s attitudes towards mercury use for artisanal mining.

This project is a collaboration between Universidad del Valle, University of Brasilia, IHE Delft and the local community councils of La Toma and Yolombo. Watch this video for more information on the project. Visit the project website for more information. 


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