By Ayele Addis Ambelu (News and Program producer) +251918718307
“In many African small-scale gold mining communities, the reliance on mercury for gold extraction poses severe environmental and health challenges. According to recent reports by researchers and community experiences, mercury pollution has contaminated water sources, posing risks to both aquatic life and human health. The indiscriminate use of mercury in processing gold has led to significant environmental degradation, affecting biodiversity and agricultural lands surrounding mining areas. The long-term impacts on livelihoods are profound, as communities reliant on these resources face compromised water quality and reduced agricultural productivity due to mercury contamination.”
This quote encapsulates the common themes and issues raised in discussions about mercury use in small-scale gold mining in Africa, reflecting the environmental and socioeconomic challenges affected communities face.
As the United States Environmental Protection Agency (USEPA) noted in 1987 – “… problems related to mining waste may be rated as second only to global warming and stratospheric ozone depletion regarding ecological risk. The release to the environment of mining waste can result in profound, generally irreversible destruction of ecosystems”. Then, indeed we are in grave trouble.
The Devastating Impact of Mercury
Recent research, in a significant push for sustainable mining practices, highlights the detrimental environmental and health impacts of traditional mercury-based small-scale gold mining in Africa. At the same time, it presents a promising shift towards mercury-free methods that could mitigate these impacts and improve community livelihoods.
Mercury, a highly toxic element, is central to gold extraction in many small-scale African mining operations. The process, which involves amalgamation, separation, and burning of mercury, releases significant amounts of mercury into the environment. As noted in the research presentation by T.C. Davies, “11% of the human-generated sources of mercury come from gold production.” This mercury pollution is second only to coal combustion as a source of human-generated mercury emissions, posing severe risks to the nervous system even at low exposure levels.
The World Health Organization (WHO) underscores the toxicity of mercury, emphasizing that both elemental and methylmercury can cause severe damage to the central and peripheral nervous systems. Inhalation of mercury vapor can also lead to harmful effects on the digestive and immune systems, lungs, and kidneys, and can be fatal in extreme cases.
Environmental Pollution and Health Risks
The widespread use of mercury in gold mining has led to significant environmental pollution. Studies reviewed in the presentation show that arsenic, often found in high concentrations in both surface water and groundwater in Africa, is primarily linked to mining activities. For instance, arsenic levels in African groundwater range from 0.02 to 1760 μg L−1, while surface water can contain up to 10,000 μg L−1. These high concentrations result from the disposal and incineration of municipal and industrial wastes, as well as agricultural drains and local sediments.
Additionally, acid mine drainage (AMD), a process where sulphide minerals in rocks react with water and oxygen to form sulfuric acid, releases heavy metals like lead, mercury, and zinc into the environment. This results in highly acidic waters with pH levels sometimes below 1.0, as seen at the Iron Duke mine near Mazowe, Zimbabwe, which recorded arsenic values of up to 72 mg L−1, the highest for natural waters anywhere on Earth.
Dr. T.C. Davies elaborates on the severity of these impacts: “The release of heavy metals into the environment from small-scale gold mining operations leads to widespread contamination of water resources, affecting both human populations and wildlife. We must address these issues with effective and sustainable solutions” .
Mercury-Free Mining: A Sustainable Alternative
The push for mercury-free mining practices offers a viable and sustainable alternative in response to these severe environmental and health impacts. Mercury-free methods, such as gravity concentration and the use of alternative chemical processes, significantly reduce the ecological footprint of gold mining.
One promising mercury-free technique is using borax, a standard household product, in the gold extraction process. This method, already in use in parts of the Philippines and Mongolia, allows miners to recover more gold without the hazardous side effects of mercury. Dr. Davies notes, “Borax, as an alternative to mercury, has shown great promise in reducing environmental pollution while increasing gold recovery rates for small-scale miners. This method provides a safer and more efficient way forward”.
By adopting such practices, African small-scale miners can improve their gold recovery rates while safeguarding their health and the environment.
Why is mercury a problem?
Any of the four stages of the small-scale gold production process, namely amalgamation, separation of amalgamation, removal of excess mercury, and burning of the remaining amalgam, release mercury into the environment. As a result and along. “11% of the human-generated sources of mercury comes from gold production.
It is acknowledged to be second only (though quite far behind…) to coal combustion as a source of human-generated mercury emission in the atmosphere.
It is well known that mercury is highly toxic, causing damage to the nervous system at even relatively low levels of exposure. According to WHO: “Elemental and methylmercury are toxic to the central and peripheral nervous system. The inhalation of mercury vapor can produce harmful effects on the nervous, digestive and immune systems, lungs and kidneys, and may be fatal.
Africa’s highest grade uranium ore comes from the twin mining towns of Arlit and Akokan on the border of the Sahara desert. Today, Akokan boasts the largest underground uranium mine in the world and Niger supplies around 7.5 % of world uranium. By 2006, cumulative uranium output from Niger exceeded 100,000 tons – 56 %from underground and 44 % from open-pit mines. Nearly 35 million tons of radioactive tailings have accumulated over the years, lying uncovered near the mines, exposed to desert winds.
The tailings dump is located close to the city’s vegetable fields. Children regularly play in the radioactive rubble. The waste still retains, nearly 85 % of the original radioactivity, through substances like radium and thorium with half-lives of many thousands of years.
Until the 1980s, miners were not provided with even the most basic protective gear. They mined in t-shirts and shorts, without masks, gloves or dosimeters. According to local NGOs, doctors noticed rising rates of lung cancer, but did not raise an alarm. Countless miners have contracted lung cancer, but so far not a single case has been officially accepted as an occupational disease. Through the continued exposure to radioactive dust from tailings and the radioactive contamination of groundwater, the inhabitants of the nearby towns are also affected. In 2010, about 200,000 liters of radioactive waste spilled near Arlit, contaminating large areas of land. So far, no independent epidemiological research on the effects of radioactivity on public health has been performed in the region.
The majority of mine residue areas in South Africa are radioactive because the Witwatersrand gold-bearing ores contain almost ten times the amount of uranium than gold. In order to limit the risk of direct exposure to radioactive material, the South African Chamber of Mines has set the guideline that each tailings dump should have a 500m buffer zone surrounding it where no human settlement is allowed.
Uranium is passed on to humans either through the inhalation of fine dust particles from these tailings and can be blown as far as 20km on a windy day, or when mine water seepage enters rivers. There are well-documented health risks associated with high levels, including kidney damage and disease, neurological problems and cancer. Natural uranium levels are between 7 and 60 Bq/kg. It is also an endocrine disrupter that mimics the hormone, oestrogen, which is particularly harmful to pregnant women, causing birth defects and developmental delays in their babies.
But an estimated 1.6 million people live in informal and formal settlements on, or directly next to, tailings. In addition to accidental ingestion through the water or air, some of these communities are also directly exposed to radiation from the high levels of uranium and its byproducts (called daughter products) in the tailings. These communities are particularly vulnerable because of chronic malnutrition, a high prevalence of HIV/AIDS and substance abuse.
Improving Livelihoods Through Sustainable Practices
Transitioning to mercury-free mining benefits the environment and has the potential to enhance the livelihoods of mining communities. Healthier miners and cleaner surroundings contribute to higher productivity and a better quality of life. Educational programs and support from international organizations can facilitate this transition, providing miners with the necessary training and resources.
The research presentation calls for more stringent environmental regulations and increased awareness about the impacts of mercury. It also emphasizes the need for comprehensive studies on the risk to human health and the development of effective treatment systems for contaminated sites. Dr. Davies states, “Education and regulatory support are crucial in driving the adoption of mercury-free mining practices. Investing in these areas can ensure a healthier and more sustainable future for mining communities”.
Solution:
The path to sustainable small-scale gold mining in Africa is clear: reducing reliance on mercury and adopting environmentally friendly practices is imperative. As the research by T.C. Davies illustrates, mercury-free mining mitigates environmental pollution and enhances the health and well-being of mining communities. With continued education, support, and regulatory efforts, Africa can lead the way in sustainable and responsible gold mining.
This shift towards mercury-free mining represents a significant step in addressing the dual challenges of environmental degradation and public health risks posed by traditional mining practices. By embracing these solutions, African communities can look forward to a healthier, more sustainable future.
