Tissues inorganic mercury

Methylation of divalent inorganic mercury salt has been shown in vivo in rat intestine [61] and in vitro in human intestine [62], yet it is seldom followed by toxic effects. MeHg has been found in hen tissues [63 ] and probably in rat brain [64] after ingestion of divalent mercuric salts. 

Inza, B., F. Ribeyre, R. Maury-Brachet, and A. Boudou. 1997. Tissue distribution of inorganic mercury, methylmercury and cadmium in the Asiatic clam (Corbicula fluminea) in relation to the contamination levels of the water column and sediment. Chemosphere 35 2817-2836. 

M. S. Jimenez, R. E. Sturgeon, Speciation of methyl- and inorganic mercury in biological tissues using ethylation and gas chromatography with furnace atomization plasma emission spectrometric detection, J. Anal. Atom. Spectrom., 12 (1997), 597D601. 

The answer lies mainly in their distribution and properties. Elemental (liquid) mercury is volatile and can be inhaled. If sufficient of it enters the body, it is able to enter tissues such as the brain and cause damage, giving rise to headaches and also damaging the gums and teeth, for example. Liquid mercury, if taken into the stomach (which could occur if a child chewed and broke a thermometer, for example), would not be especially hazardous as the metal would be eliminated from the intestines in due course in the faeces. Little would be absorbed into the bloodstream. Inorganic mercury, such as occurs in salts (for example, mercuric chloride, also known as corrosive sublimate), can be absorbed from the gut and sufficient enters the bloodstream to bind to sulphur-containing... 

In tissues, its monomethylated metabolite may undergo further biotransformation. Ultimately, conversion into inorganic mercury enables the metal to bind to glutathione for biliary excretion. However, much of this complex can also be reabsorbed by the gastrointestinal tract. Such bile-hepatic recycling permits redistribution of mercury. 

Mercury will cross the placental barrier. In mammalian tissue, organic mercury, especially alkyl mercury, is converted to inorganic forms but not vice versa. Inorganic forms of mercury (not organic forms) induce a metallothionein. Inorganic mercury concentrates mainly in the kidney. Organic mercury compounds, being lipid soluble, concentrate in adipose tissue and the brain. Elimination is primarily in the urine and the feces, with small amounts in breath, sweat, and saliva. 

Mercury can enter and accumulate in the food chain. The form of mercury that accumulates in the food chain is methylmercury. Inorganic mercury does not accumulate up the food chain to any extent. When small fish eat the methylmercury in food, it goes into their tissues. When... 

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