Mercury is a naturally occurring metal found in the air, water, and soil in several different forms.

  • Elemental mercury, or metallic mercury, is a shiny, silver-white, liquid used in some thermometers, dental fillings, light bulbs, and other products. If heated, it is a colorless, odorless gas.
  • Organic mercury compounds result when mercury combines with carbon. The most common of these, methylmercury, is produced mainly by microscopic organisms in the water and soil.
  • Inorganic mercury compounds, or "salts," result when mercury combines with other elements, such as chlorine, sulfur, or oxygen.

Sources of Exposure

The most common way people are exposed to mercury is by eating fish that contain methylmercury. Mercury is released into the air by, among other practices, the burning of hazardous material and the mishandling of mercury products. Mercury in the air then settles into water or onto land where it can be washed into water. Microorganisms in the water change this mercury into methylmercury, a highly toxic form of mercury that builds up in fish, shellfish, and animals that eat fish. The levels of methylmercury in fish and shellfish depend on what they eat and how long they live.

Less common sources of exposure include household products that contain mercury, such as skin-lightening creams, antiseptic creams, and ointments, and broken products that contained metallic mercury. The most common of these products are mercury fever thermometers and compact florescent light bulbs (CFLs). When products that contain metallic mercury break mercury vapor inhalation can occur. This is particularly dangerous in warm or poorly-ventilated indoor spaces.

Health Risks

Exposure to high levels of mercury can harm the brain, heart, kidneys, lungs, and immune system of people of all ages. Very young children and fetuses, however, are most susceptible to the effects of mercury. High levels of methylmercury in the bloodstream of unborn babies and young children have impaired cognitive thinking, memory, attention, language, and fine motor and visual spatial skills. Given the effects of mercury exposure on fetuses, pregnant women and women who are planning pregnancies should make special considerations before eating fish.

In addition to age, several factors affect the severity of health effects from mercury exposure. These include the form of mercury an individual is exposed to (methylmercury and metallic mercury vapors are most harmful); the amount of mercury an individual is exposed to; the duration of exposure; and the route of exposure (inhalation, ingestion, skin contact, etc.).

What You Should Do

Replace mercury thermometers

Since 2002 it has been illegal to sell mercury fever thermometers in Rhode Island. Replace your mercury thermometers with non-mercury alternatives, such as digital thermometers and disposable temperature strips. Be sure to follow proper recycling and disposal practices.

Take precautions when thermometers and other products containing mercury break

Proper clean-up procedures should be followed if a mercury fever thermometer breaks or a compact florescent light bulb breaks to ensure that mercury does not vaporize.

Don't eat fish with elevated levels of mercury

Avoid eating types of fish which tend to have higher levels of mercury and fish that lived in mercury contaminated areas, - like urban ponds. more