What is Mercury?

How Toxic is Mercury?

How Are People Exposed to Mercury?

How to Protect Yourself From Mercury Exposure

Health Effects

Main Symptoms

What to Do if a Mercury Spill Occurs

Mercury Information Home

Health Effects

Elemental mercury and mercury compounds pose an extreme health hazard, particularly to developing fetuses, young children and frail persons of any age. Long-term exposure to mercury can cause permanent damage to the brain, kidneys and the development of unborn babies. Mercury has not been shown to cause cancer in humans. Organic mercury from eating contaminated fish or grain may cause greater harm to the brain and to developing fetuses than to the kidneys. Mercury vapors may cause greater harm to the brain, while inorganic mercury salts in water supplies or in contaminated foods may cause greater harm to the kidneys.

At high levels, metallic mercury can affect the nervous system and the developing fetus. Short-term exposure to high levels of inorganic or organic mercury produce similar health effects, but full recovery is more likely once the body is free of contamination. Long-term exposure to lower levels of mercury is a greater threat to overall health, and may be more insidious because it causes harm before symptoms are evident. The detrimental effects of low-level, long-term exposure may be irreversible, particularly to the brain and kidneys. Mercury has not been shown to cause cancer.

Mercury easily enters the body through several routes, but it may take many months for the body to purge itself of the poisonous metal. Mercury vapors can be breathed - among the most hazardous exposures to elemental mercury. Handling the liquid metal also allows mercury to enter the body through pores of the skin. Mercury leaves the body mostly through the urinary and digestive tracts.

Different forms of mercury and the way in which people are exposed will determine how severe and what kind of effect the poisoning produces. Organic mercury, ingested by eating contaminated fish or grain, may cause greater harm to the brain and to developing fetuses than to kidneys. Exposure to elemental mercury and its vapor may cause greater harm to the brain, while inorganic mercury salts in water supplies and contaminated foods may affect kidneys to a greater extent.

Medical professionals test for mercury poisoning by drawing blood and taking urine samples, then examining the specimens with special laboratory equipment. The tests are reliable, accurate and easily available. In some cases - particularly when mercury levels in the body are extremely high "chelation" therapy is necessary to speed the expulsion of the toxic metal from the body. Chelation therapy involves introducing a chemical into the bloodstream that combines with mercury to aid in removing the metal from the body.