People in the U.S. are mainly exposed to methylmercury, an
organic compound, when they eat fish and shellfish that contain
methylmercury. Whether an exposure to the various forms of
mercury will harm a person's health depends on a number of
factors. Almost all people have at least trace amounts of
methylmercury in their tissues, reflecting methylmercury's
widespread presence in the environment and people's exposure
through the consumption of fish and shellfish. People may be
exposed to mercury in any of its forms under different
circumstances. The factors that determine how severe the health
effects are from mercury exposure include these: - The chemical
form of mercury. - The dose. - The age of the person exposed
(the fetus is the most susceptible). - The duration of exposure.
- The route of exposure -- inhalation, ingestion, dermal
contact. - The health of the person exposed. Mercury exists in
three chemical forms. They each have specific effects on human
health. - Elemental mercury. - Other mercury compoun