The Effects of Mercury Poisoning

Nearly everyone has been exposed to mercury in seafood, on the job or from medical or dental procedures. All forms of mercury have toxic effects on the nervous system. Mercury poisoning can have short-term and long-term effects.

• A closeup view of elemental mercury.

Types

• Naturally-occurring, elemental mercury is a shiny, silver liquid that heats to a colorless, odorless gas. Inorganic mercury refers to mercury-containing compounds in powder or crystal form. Organic methylmercury is produced by microorganisms.

Sources

• Some industrial practices produce inorganic mercury compounds.

  Elemental mercury is used in fluorescent light bulbs, glass thermometers, electrical switches and older dental fillings. Sources of inorganic mercury include manufacturing plants, ore mining and burning coal. Methylmercury is present in soil, water, tissues of fish and shellfish, some antiseptics and thimerosal.

Exposure

• Several factors influence the severity of mercury poisoning: the form of mercury, amount of mercury, method of exposure, duration of exposure, age and health status.

Effects

• Elemental mercury is harmful only in vapor form when tiny droplets are inhaled. Inorganic mercury and organic methylmercury are poisonous when swallowed. Effects of methylmercury are not immediate but can appear years later.

Symptoms

• Elemental mercury poisoning causes tremors, mood swings, irritability, insomnia, muscle weakness or atrophy and headaches. Exposure to inorganic mercury causes skin rashes, memory loss, mental disturbances and muscle weakness. Methylmercury poisoning causes impaired speech, hearing and walking; numbness and tingling in hands, feet and mouth and developmental defects in fetuses, infants and children.