mercury poisoning


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mercury poisoning,

tissue damage resulting from exposure to more than trace amounts of the element mercurymercury
or quicksilver
[from the Roman god Mercury], metallic chemical element; symbol Hg [Lat. hydrargyrum=liquid silver]; at. no. 80; at. wt. 200.59; m.p. −38.842°C;; b.p. 356.58°C;; sp. gr. 13.55 at 20°C;; valence +1 or +2.
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 or its compounds. Elemental mercury (the silver liquid familiar from thermometers) is the most common occupational source. Exposure typically comes from inhaling mercury vapors. Inorganic salts of mercury (e.g., mercurous chloride, or calomel) are used in some products to inhibit the growth of fungi and bacteria. Organic mercury compounds, especially methylmercury, are more toxic than other forms because they easily cross cell membranes. They are most often ingested in contaminated fish.

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, numbness in limbs, blindness, and inability to speak. Some studies have connected maternal mercury exposure to fetal damage. 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.

Mercury has become an environmental pollutant in areas where eroding mercury-bearing rock or agricultural and industrial wastes containing the metal escape or are discharged into waterways. Mercury also is released into the atmosphere when coal is burned. Elemental mercury and mercury salts, although fairly inert when deposited on the bottom of waterways, are converted into organic mercury, typically methylmercury, by microorganisms. This compound then enters the food chain where it is biomagnified up to 100,000 times in predacious fish. Consumption of toxic fish and of game birds and mammals that feed on fish is the main risk to humans. Minamata disease was named after the occurrence, in the 1950s and 1960s in Minamata, Japan, of many cases of severe mercury poisoning. It was found that a chemicals factory was discharging mercury-containing wastes into the local waters, contaminating fish that residents caught for food.

Mercury has long been known to be toxic; the phrase "mad as a hatter" refers to the 19th-century occupational disease that resulted from prolonged contact with the mercury used in the manufacture of felt hats. Some workers today, especially laboratory technicians, nurses, and machine operators, continue to be exposed to mercury on the job. 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. The Minamata Convention, adopted in 2013, requires its signatories to reduce both mercury use and emissions. Mercury, which has been used in medicines for hundreds of years, continues to be used in dental amalgams and various medicaments that deliver minimal exposures. Most other medical uses have been banned or are being phased out, but mercury use in industry is increasing.

See also water pollutionwater pollution,
contamination of water resources by harmful wastes; see also sewerage, water supply, pollution, and environmentalism. Industrial Pollution
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.

Bibliography

See L. Elbert, Mercury Poisoning in Man (1978); P. A. and F. M. D'itri, Mercury Contamination: A Human Tragedy (1988).

Mercury Poisoning

 

mercurialism, an occupational disease; poisoning by metallic mercury or its compounds.

Mercury poisoning results from contact with fumes of mercury metal or its amalgams and readily decomposing compounds or from the accidental ingestion of mercury salts. Acute mercury poisoning is characterized by fever and necrotic ulcerative lesions of the oral and intestinal mucosae. Severe kidney lesions are dominant in poisoning by mercury salts. Chronic mercury

Table 1. Launches of Mercury spacecraft
code designation of vehicleDate of launonElements of orbit (km)Period of revolution(min)Length of flightType of flight (name of astronaut)
  perigeeapogeeinclination   
MR-3 .....May 5, 196115 minSuborbital (A. Shepard)
MR-4 .....July 21, 196116 minSuborbital V. Grissom)
MA-6 .....Feb. 20, 1962161.4262.832.588.24 hr 55 minOrbital (J. Glenn)
MA-7 ....May 24, 1962160.9268.432.588.34 hr 56 minOrbital (M. Carpenter)
MA-8 ....Oct. 3, 1962161.4278.232.5688.99 hr 13 minOrbital (W. Schirra)
MA-9 .....May 15, 1963160.926732.588.734 hr 20 minOrbital (G. Cooper)

poisoning involves damage to the central nervous system (increased excitability and rapid fatigability of neural processes, increasing involuntary tremor in the extremities). Mental changes and severe systemic exhaustion (mercury cachexia) develop with the passage of time. Mercury’s ability to penetrate the placenta can lead to poisoning of the fetus in pregnant women.

Mercury poisoning is treated with antidotes and drugs that help to remove the mercury from the body. Hydrogen sulfide baths are also useful. The condition can be prevented by observing safety standards in dealing with mercury.

REFERENCES

Kevork’ian, A. A. ProfessionaVnye neirotoksikozy. Minsk, 1955.
Drogichina, E. A. Prefessionarnye bolezni nervnoi sistemy. [Leningrad] 1968.
Trakhtenberg, I. M. Khronicheskoe vozdeistvie rtuti na organizm. Kiev, 1969.

A. A. BEZRODNYKH

References in periodicals archive ?
The US National Institutes of Health said that mercury poisoning is a slow process that can take months or years.
But, stresses Eric Rimm, professor of epidemiology and nutrition at the Harvard School of Public Health, "For most individuals it's fine to eat fish every day." With the exception of pregnant women and children, you can safely eat fish every day without worry of mercury poisoning as long as you limit the amount of high mercury fish to two servings per week.
This prompted calls for the declaration of a health crisis and the immediate evacuation and relocation of residents who showed symptoms of Minamata disease, named after the fishing village in Japan that in the late 1950s suffered the effects of mercury poisoning. The residents exhibited symptoms that ranged from numbness in the hands and feet, muscle weakness, narrowing of the field of vision, and damage to hearing and speech.
The effects of mercury poisoning are widespread, and unfortunate.
Children are at increased risk for exposure to mercury poisoning because they are more likely to play on floors and because their smaller lung capacity facilitates increased breathing of mercury vapors (2,3).
This is one of the first symptoms of mercury poisoning, he explained.
Sofia Ashraf's "Kodaikanal Won't" addresses alleged mercury poisoning of former workers in a Tamil Nadu town and attracts nearly 2m YouTube views
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Dr Khwaja shared the research work on Mercury Poisoning Dentistry: High level indoor air mercury contamination at selected dental sites" carried out by SDPI at dental sites in Pakistan.
However, widespread seafood fraud can lead to fish contaminated by heavy metals being sold to those who are vulnerable to mercury poisoning, such as pregnant women and children.
In all, 900 people died and 2,265 people are still suffering from mercury poisoning.