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Fact Sheet - Mining and Ore Processing and Mercury Pollution


Estimated Population at Risk at Identified Sites: 1.5 Million People*
Estimated Global Impact: 2 to 5 Million People*

What Is Mining and Ore Processing?

Large-scale mining and ore processing operations can be found throughout the world. Many large-scale mines have on-site or nearby ore processing facilities where extracted ore is sent for crushing, washing, and physical or chemical separation. Not all mined materials are dangerous, but many non-dangerous materials are found in rock that also contains heavy metals, which can be released during the ore extraction and processing.

Which Mining Processes Create Mercury Pollution?

Mercury can be released through mercury mining and through the use of mercury in mining processes for other metals. Mercury is mined as a primary element for use in materials such as thermometers and fluorescent light bulbs, and can be commonly found in the ore of other mined materials such as coal. Mercury is frequently used in the gold mining process to separation gold from silt.

What Are the Human Exposure Pathways for Mercury from Mining and Ore Processing?

Waste rock and mine tailings can release toxins into the environment if not stored or disposed of properly. In many cases, waste rock and tailings are left out in the open where they are exposed to the elements, and mercury can be washed into water systems by rainfall, or can leach into the soil. Mercury that is used in gold mining can also be released into the environment as liquid or vapor. When mercury enters water systems, it can bio-accumulate in the bodies of aquatic animals and enter the food chain.

What Are the Health Risks Associated with Mercury?

Health risks associated with mercury vary depending on the type of mercury, level of exposure, and the pathway. Inhalation of mercury vapor is particularly hazardous for kidneys, the central nervous system, and the respiratory and cardiovascular systems.1 Exposure to other forms of mercury, and in particular the methylmercury that accumulates in fish, can also lead to problems with the kidneys, lungs, and central nervous system, in addition to arthritis, reproductive problems, loss of memory, psychosis, and in some cases, death. Children exposed to mercury contamination have a higher risk of developmental complications.

*Population estimates are preliminary and based on an ongoing global assessment of polluted sites.


[1]: Toxicological Profile for Mercury.” U.S. Department of Health and Human Services. March, 1999.
Available at http://www.atsdr.cdc.gov/toxprofiles/tp.asp?id=115&tid=24.