Biological Effects of Mercury

There is no known biochemical reaction in organisms that applies Hg as an essential element. Mercury is the only metal which is a liquid at ordinary temperatures. The boiling point of this metal is 357 °C. This temperature is relatively low for metals and its vapor pressure is significant even at room temperature. The threshold limit value (TLV) of elemental mercury is 0.05 mg/m- a value that is less than the equilibrium vapor pressure at ambient temperatures. However, in the mercury miners in Sicily, where the mercury occurs in shales, the miners are exposed to elemental mercury vapor, which content in the air may reach toxic levels of about 5 mg/nr Another source of exposure in mines is the mercury-containing dust. [Pg.407]

We can see accordingly, that in Sicily mines the TLV was exceeded by 10 fold. The TVL of organic mercury is set at 0.01 in recognition of their greater toxicity. [Pg.407]

Mercury-containing mineral, vermillion, has for centuries been used as a pigment for oil based paint. Mercnry poisoning among artists has occurred as a result of licking the brush to get a fine point. [Pg.408]

Organic derivatives of mercury are more hazardous than the simple inorganic salts because they are lipid soluble and hence bioconcentrate. These species are able to cross the blood-brain barrier, thereby causing the neurological symptoms associated with mercury intoxication. [Pg.408]

Elemental mercury is mainly hazardous as vapor. There is less danger of absorbing the metal for the digestive tract. Like the alkylmercurials, elemental Hg affects the central nervons system, accompanied with such symptoms as tremors, irritability, and sleeplessness. Kidney damage is also reported due to influence of inorganic mercury salts due to a complexation of mercury by the protein metallothionein, which accumulates in the renal tubules. [Pg.408]

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