Overview

Mercury Pollution is a global environmental challenge posing a significant threat to human health and to the environment. Understanding the major sources of mercury emissions is crucial for developing effective strategies to mitigate their impact. Mercury is a naturally occurring element released into the environment through various anthropological activities which lead to the widespread contamination of air, soil, and water. The health effects that come with mercury exposure can particularly affect vulnerable populations such as pregnant women, children, and infants and can lead to neurological disorders, cardiovascular diseases, and developmental delays.

The contamination of mercury in the environment can disrupt ecosystems and threaten biodiversity. Elevated mercury levels in fish for instance can lead to reduced survival rates and population decline in the species and affect humans when they consume such species. Mercury is found to be a transboundary issue because it can travel long distances through the atmosphere to various other regions across the globe.

Major Sources

  • Artisanal and Small-Scale Gold Mining (ASGM). Artisanal and small-scale gold mining is the main contributor to global mercury emissions. Miners, especially those in developing countries use mercury to extract gold from ore which leads to the release of large quantities of mercury into the atmosphere, water bodies, and the environment in general.
  • Industrial Processes. Industrial processes such as metal smelting, cement production, waste incineration, etc. also contribute significantly to mercury pollution. Such processes release mercury into the air, soil, and water, thus posing risks to human health. To reduce mercury pollution from such industries, it is important to promote cleaner production methods and improve pollution control technologies. 
  • Waste Management. Improper waste management practices such as the disposal and recycling of electronic waste (e-waste) and mercury-containing products can lead to the release of mercury into the environment. Recycling processes such as open burning can release mercury vapors into the atmosphere. Improving waste management practices such as safe handling and disposal of mercury-containing waste is therefore important. 
  • Agricultural Activities. Agricultural activities that include the use of mercury-containing pesticides and fertilizers can also contribute to mercury pollution in the environment. As such, runoff from agricultural fields can transport mercury into waterbodies and where it bioaccumulates in aquatic organisms. Thus, promoting sustainable agricultural practices that minimize the use of mercury-based chemicals can help reduce the amount of global mercury pollution.
  • Coal Combustion. Coal combustion is another major source of mercury emission. Mercury is naturally found in coal deposits and when coal is burnt, it releases mercury into the atmosphere. Adopting cleaner technologies and implementing emission control measures can help reduce global mercury pollution.

Worldwide Emissions

How much mercury is emitted worldwide each year? Estimates of annual global mercury emissions from anthropogenic sources are about 2,220 metric tons per year, including mercury that is re-emitted. The world map below provides information about the distribution.

Geospatially distributed (total) mercury emissions to air from anthropogenic sources in 2015 (g/km2/a) from all sectors. (Click to enlarge.)

Source: Development and application of an updated geospatial distribution model for gridding 2015 global mercury emissions (Figure 3)as developed for the 2018 Global Mercury Assessment and its Technical Background Report.

Listed below is a sortable table showcasing the top sources of mercury Pollution:

SourceAmount (kg)
Artisanal and Small-Scale Mining837,658
Stationary Combustion of Coal473,777
Nonferrous Metals Production326,657
Cement Production233,168
Waste from Products146,938
Vinyl Chlorine Monomer58,268
Biomass Burning51,860
Ferrous Metals Production39,903
Chlor-alkali Production15,146
Waste incineration14,944
Oil Refining14,377
Stationary Combustion of Oil and Gas7,130
Cremation3,768

Source: Technical Background Report of the Global Mercury Assessment, 2018.

Impacts of Mercury Pollution

The impacts of global mercury pollution are far-reaching

Human Health: Exposure to mercury can lead to severe neurological and developmental problems, especially in fetuses and young children. It can also affect adults, causing cognitive and motor function impairment, and other health issues.

Ecosystems: Mercury accumulates in aquatic ecosystems, with microorganisms converting it to methylmercury. Methylmercury biomagnifies as it moves up the food chain, leading to high concentrations in predatory fish and marine mammals. This poses risks to humans and wildlife consuming the contaminated seafood.

Biodiversity: Mercury pollution can have toxic effects on various species, therefore disrupting ecosystems and leading to declines in biodiversity.

The Africa Context

Efforts to address mercury pollution in Africa include:

Minamata Convention: Reducing global mercury pollution requires a combination of policy measures, technological advancements, and international cooperation to mitigate its adverse effects on human health and the environment. The Minamata Convention on Mercury is a global treaty addressing mercury pollution. It aims to regulate and reduce mercury emissions and releases and promote safe handling and disposal of mercury-containing products. Countries are encouraged to develop action plans to control mercury pollution, promote mercury-free alternatives, and enhance public awareness about the risks associated with mercury exposure. Several African countries have ratified and are implementing the Convention.

Capacity Building: International organizations and NGOs are working to build capacity within African countries to manage and reduce mercury pollution. This includes training miners on safer mining practices and assisting governments in developing regulations.

Alternative Technologies: Promoting alternative technologies that eliminate or reduce the use of mercury in gold mining is crucial. These technologies are often more efficient and environmentally friendly.

Research and Monitoring: Research on the extent of mercury pollution and its impacts in different regions of Africa helps guide policy decisions and interventions.

Community Engagement: Engaging with communities to raise awareness about the risks of mercury exposure and involving them in sustainable solutions is crucial for long-term success.

Addressing mercury pollution in Africa requires a multifaceted approach that involves regulatory measures, technological innovation, awareness-raising, and international collaboration to protect both human health and the environment.