Mercury & Human Health
Women who expect to become pregnant or are pregnant should not eat mercury-contaminated fish. Mercury affects brain and nervous system development in the fetus. Affected children show lowered intelligence, impaired hearing and poor coordination. Their verbal and motor skills may be delayed.
Mercury poisoning can cause severe neurological and kidney damage. Acute exposure can affect the respiratory and gastrointestinal systems. Organic mercury can cross the blood-brain barrier and cause irreversible nervous system and brain damage, e.g., loss of motor control, tingling sensations in the fingers and toes, numbness in limbs and around the mouth, tunnel vision or blindness, and loss of ability to speak. Long-term exposure to mercury can result in symptoms that get progressively worse and lead to personality changes, stupor and coma. Mercury poisoning can be confirmed by urine tests. Chelation therapy is used for poisoning with elemental mercury and mercury salts; there is no treatment for organic mercury poisoning.

Products That Contain Mercury
Mercury metal has many uses. Because of its high density, it is used in barometers and manometers. With its high rate of thermal expansion that is fairly constant over a wide temperature range, mercury is used extensively in thermometers and thermostats. Mercury is important as an electrical contact for switches. Mercury conducts the charge in fluorescent lamps. Mercury-vapor lamps, which emit light rich in ultraviolet radiation, are used for street lighting, in water treatment plants as a disinfectant, and in tanning beds. Mercury is used as an electrode in the production of chlorine and sodium hydroxide and in certain electric batteries.

Mercury compounds have many uses. Calomel (mercurous chloride, Hg2Cl2) is a standard in electrochemical measurements and in medicine as a purgative. Mercuric chloride (corrosive sublimate, HgCl2) is an insecticide, a rat poison, and a disinfectant. Mercuric oxide is used in skin ointments. Mercuric sulfate is a catalyst in organic chemistry. Vermilion, a red pigment, is mercuric sulfide; another crystalline form of the sulfide (also used as a pigment) is black. Mercury fulminate, Hg(CNO)2, is a detonator. Mercury forms many organic compounds. Mercurochrome (in 2% aqueous solution) is used in medicine as a topical antiseptic.

Most mercury pesticides have been withdrawn from the U.S. market, and many countries banned ocean dumping of mercury and other pollutants in 1972. Production of mercury-containing interior and exterior paints in the United States was phased out in 1991. Mercury, which has been used in medicines for hundreds of years, continues to be used in various folk remedies that deliver exposures. The use of mercury in dental amalgam for tooth fillings has stirred escalating controversy in recent years. Most other medical uses have been banned or are being phased out, but mercury use in industry is increasing.