SYNONYMS: Hg(2+) | Hg2+ | Mercuric ion | Mercury ion | Mercury(2+) | Mercury(2+) ion | Mercury(II) | Mercury(II) cation | Mercury(II) ion | Metallic mercury | Quicksilver
Hence the atomic symbol for Mercury is Hg, which comes from Greek name, Hydrargyrum, meaning “liquid silver”.
The most devastating tragedies related to Mercury (Hg) toxicity in recent history include Minamata Bay and Niagata, Japan in the 1950s, and Iraq in the 1970s.
Hair has been used in many studies as a bioindicator of mercury exposure for human populations. At the time of hair formation, mercury from the blood capillaries penetrates into the hair follicles. As hair grows approximately 1 cm each month, mercury exposure over time is recapitulated in hair strands. Mercury levels in hair closest to the scalp reflect the most recent exposure, while those farthest from the scalp are representative of previous blood concentrations.
Sequential analyses of hair mercury have been useful for identifying seasonal variations over time in hair mercury content, which may be the result of seasonal differences in bioavailability of fish and differential consumption of piscivorous and herbivorous fish species. Knowledge of the relation between fish-eating practices and hair mercury levels is particularly important for adequate mitigation strategies.
Mercury occurs in deposits throughout the earth, often as cinnabar (mercuric sulphide) which, when ground forms the red pigment, vermilion.
Mercury is used in thermometers, barometers, manometers, sphygmomanometers, float valves, mercury switches, mercury relays, though mercury in thermometers and sphygmomanometers is being phased out.
Used in fluorescent lighting because electricity passed through mercury vapor in a fluorescent lamp produces short-wave ultraviolet light, which then causes the phosphor in the tube to fluoresce, making visible light.
Mercury binds to both inorganic elements (chloride, selenium, oxygen and many others) and organic (containing carbon like Methyl compounds). Poisoning can result from exposure to water-soluble forms of mercury such as mercuric chloride or methylmercury, by inhalation of mercury vapor, or by ingesting any form of mercury.
Hg is a liquid at room temperature, known as metallic or elemental Mercury and is used in dental amalgams and various domestic and industrial applications.
Unfortunately, at room temperature, metallic or elemental Mercury gives off a gaseous form of Hg that is lipophilic (attracted to fatty tissue) and readily absorbed upon inhalation and then easily able to cross the placenta or the blood-brain barriers.
To make matters worse, once Mercury is in a human cell, it is rapidly oxidized by a catalase enzyme into inorganic Mercury (Hg2+), which in the neuron cells of the brain can be retained for years. Organic Mercury compounds like Methylmercury (MeHg) from fish or Ethyl mercury from the compound Thimerosal found in some vaccines (especially flu-vaccines) and Phenyl mercury can, however, penetrate into the blood brain barrier whereupon they are converted to inorganic Hg and then trapped in the brain or nervous tissue for years.
Adding fuel to this fire of body mercury bio-accumulation, is the realisation that individuals can be exposed to multiple sources of mercury at once. Fish consumption, dental amalgams and occasional vaccine shots combined with other exposures outlined below, make Mercury a toxic force to be acknowledged.
Ref: Toxno Mercury Profile
and Additional references used on Toxno
and Mercury exposure and health impacts in dental personnel
and Mercury (the element) on Wikipedia