Environmental Mercury
Mercury is a chemical element with the symbol Hg, and historically has been widely used in many products as well as manufacturing and mining processes. Mercury was used in gold and silver mining beginning 3,000 years ago, and this process is still used by small-scale miners in South Africa and South America. Mercury is in the air we breathe, the food we eat, and the water we drink. 'Silver' dental fillings (amalgams) are actually about 50% mercury. Some vaccines, eye drops, and mascara still contain mercury. Mercury is used to manufacture widely-used chemicals that are utilized to make many common products including high-fructose corn syrup, bleach, polyurethane flooring, toothpaste, and PVC plastics. Mercury is contained in the emissions from coal-burning power plants and cement kilns.
Mercury is also highly toxic. For almost 3000 years, mercury-poisoning ("mercurialism") has occurred and been given different disease names depending upon the mercury species as well as the age and particular symptoms of the people affected. Some more notable disease names for mercurialism include "Mad Hatter's Disease" in hat makers due to inorganic mercury vapor fumes, "Acrodynia" (aka "Pink Disease") in infants due to mercurous chloride in baby teething powders, and Minimata Disease due to ingestion of fish with very high levels of methylmercury caused by mercury releases from a vinyl chloride plant.
Mercury contamination is a global health issue. The health concerns go far
beyond autism to include many other health conditions affecting adults and
particularly children. A good overview of the global health concerns, as
well as sources of mercury contamination, can be found in the document
"Hating the Child Brain Drain - Why We Need to Tackle Global Mercury
Contamination" by the Stay Healthy, Stop Mercury Campaign."
Below is a partial list of common mercury compounds and sources of exposure:
- Elemental Mercury Hg0 – dental amalgams, chlor-alkali manufacturing process
- Inorganic Mercury Hg2+ -- emissions from coal and cement kiln plants
- Organic Mercury – mercury that has a carbon atom attached
- Methylmercury – bacteria convert inorganic mercury into methylmercury. These bacteria are eaten by predators that in turn are eaten by larger predators (e.g. tuna) in a process called bioaccumulation. Since large predators such as tuna cannot excrete mercury, a mature fish predator can contain a high amount of methylmercury.
- Ethylmercury, a.k.a. “Thimerosal” – a manufactured organic mercury compound that does not occur in nature. Used initially as a fungicide and later as a preservative in vaccines, mascara, and eye drops.
- Mercury salts – manufactured compounds. Past uses include mercurous chloride in baby teething powders and mercuric chloride as an antiseptic (brand name “Mercurochrome”). Current uses include mercuric fulminate in detonators for explosives.
Environmental Mercury and Autism
Other Sources of Atmospheric Mercury
Compact Flourescent Lightbulbs
Featured Resource: MercNet: Tracking Mercury in Air,
Water, Land, Fish and Wildlife.
Check out the new online library of mercury metadata from across North America! Click here