Mercury is the only common metal that is a free-flowing liquid at room temperature. It is slightly volatile in room temperature and becomes solid when subjected to a pressure of 7640 atmospheres. The metal dissolves in nitric or concentrated sulfuric acid.
The chief ore is cinnabar; Spain and Italy produce about 50% of the world?s supply of the metal. The commercial unit for handling mercury is the ?flask,? which weighs about 76 pounds. The metal is obtained by heating cinnabar in a current of air and by condensing the vapor. The metal is widely used in laboratory work for making thermometers, barometers, diffusion pumps and many other instruments. It is used in making mercury vapor lamps, advertising signs, mercury switches and other electronic apparatus. Other uses are in making pesticides, dental preparations, antifouling paint, batteries and catalysts.
The most important salts are mercury chloride (a violent poison), mercurous chloride (occasionally still used in medicine), mercury fulminate (detonator widely used in explosives) and mercuric sulfide (a high-grade paint pigment).
Mercury is a virulent poison and is readily absorbed through the respiratory tract, the gastrointestinal tract, or through unbroken skin. Most human exposure is by inhalation. Air saturated with mercury at 20 degrees C contains a concentration that exceeds the toxic limit many times. Mercury vapor diffuses across the alveolar membrane without difficulty. It is lipid soluble therefore it can get into the blood stream and has a strong affinity for the central nervous system. The danger increases at higher temperatures thus it?s important that mercury be handled with care.
... heavy metals, such as zinc, copper, chromium, iron, ... times that of water. The heavy metals most often implicated in human poisoning are lead, mercury, arsenic, and cadmium. Some ... requires hospitalization. Chelation therapy is effective in treating lead, mercury, and arsenic poisoning, but is not useful in treating ...
Chronic mercury poisoning causes irreversible brain, liver and kidney damage. For example, Minamata disease was discovered in 1956 and in 1968 it was announced that it was a pollution disease caused by the Chisso Co. Ltd. The Chisso Company polluted Minamata Bay of Japan with factory wastewater that contained methyl mercury. The methyl mercury got into the fish and people of Japan ate the fish and got the disease. The methyl mercury that entered the body mainly attacked the central nervous system, including the brain and caused various symptoms including numbness and unsteadiness in the legs and hands, tiredness, ringing in the ears, narrowing of the field of vision, loss of hearing, slurred speech, and awkward movements. Some early severe victims of Minamata disease went insane, became unconscious, and died within a month of the onset of the disease. There are also victims with chronic symptoms, such as headaches, frequent tiredness, loss of the senses of smell and taste, and forgetfulness, which are not easily visible but make daily life difficult. Moreover, there are congenital Minamata disease patients, who were born with handicaps after being attacked by methyl mercury while in the wombs of their mothers who consumed polluted fish. No fundamental cure for Minamata disease has yet been discovered, so treatment consists of attempts to lessen the symptoms and physical rehabilitation therapy.
Bibliography Klaassen, Curtis D. Casarett & Doull?s Toxicology The Basic Science of Poisons, 1996 McGraw-Hill, p 710 Microsoft Encarta Online Encyclopedia 2000. ?Mercury (element)? //encarta.msn.com