Mercury


Most of us can remember playing with mercury at some time as kids. The bright shiny silver liquid that scattered into countless little blobs which looked solid, but were impossible to pick up. Mercury isn't just a toy for kids to play with, it has been used for centuries in thermometers and barometers to tell the temperature and forecast the weather, as part of the hat making process and in industrial lighting applications.

Is there a “dark side” to Mercury?

Mercury is an element that occurs naturally in our environment. It usually exists as metallic mercury or inorganic mercury compounds, which appear to be relatively benign. However, organic mercury or ethylmercury can be ingested into the body where it accumulates, and organic mercury has been connected to health problems. Mercury related health problems are primarily associated with brain and spinal cord diseases and can cause paralysis, brain damage, blindness and even death. Ethylmercury is felt to be particularly harmful to infants or fetuses whose mothers are exposed to mercury.

How Do We Get Exposed to Mercury?

There are primarily three ways people may be exposed to mercury:
  • Eating mercury contaminated fish or shellfish

  • Dental fillings (amalgams)

  • Through vaccines (some contain a preservative called Thimerosal
    • )
How Does Mercury Get into Fish?

Simplistically, through the environment. Some industrial processes and the burning of coal for generation of electricity put mercury vapor into the air. Rain then washes the mercury into the oceans, lakes and rivers, where fish ingest it. Larger fish eat the smaller fish and the level of mercury in the larger fish grows. When a person eats the fish, they have now ingested the mercury. It appears that a person can minimize their consumption of fish-borne mercury by either limiting their consumption of fish or eating smaller fish The EPA provides a website that offers general information, fish advisories and links to sites where more specific and targeted information can be found.

What About Dental Fillings?

Amalgam (silver) fillings contain 50% of mercury by weight. There is some evidence that over the life of the filling the amalgam gives off mercury vapor that could be potentially harmful. The use of mercury in dentistry is a very contentious issue since the American Dental Association maintains the position that "There is no sound scientific evidence supporting a link between amalgam fillings and systemic diseases or chronic illness''. However, a number of European countries no longer allow the use of mercury based amalgams. Other materials that don't include mercury in their makeup (i.e. ceramic), have been developed for making fillings.

Mercury in Our Medicines?

A mercury-based preservative called “THIMEROSAL” has been used in vaccines since the 1930's. It is present in miniscule quantities and a study by the Institute of Medicine found that the evidence was inadequate to support a causal relationship between the use of Thimerosal in childhood vaccines and the development of neurodevelopmental disorders.” However, the same report did recommend that the removal of Thimerosal would be a prudent measure particularly for “any biological product to which infants, children, and pregnant women are exposed.” Partly as a result of this recommendation the FDA is working with vaccine manufacturers to eliminate the use of Thimerosal in all vaccines.

By Murray Anderson           


Related Links:

  • Fish Advisories
    An EPA website which provides information on the mercury content of fish.