Mercury compounds, organic toxicity

Organic mercury compounds, especially phenyl and methoxyethyl mercury may also be biotransformed into inorganic mercury by cleavage of the carbon-mercury bond. Although such compounds are more readily absorbed than inorganic mercury compounds, the toxicity is similar. 

DFG MAK Confirmed Animal Carcinogen with Unknown Relevance to Humans SAFETY PROFILE Poison by ingestion and subcutaneous routes. See also MERCURY COMPOUNDS, ORGANIC. An experimental teratogen. When heated to decomposition it emits very toxic fumes of Hg and PO. ... 

SAFETY PROFILE Poison by intraperitoneal route. See also MERCURY COMPOUNDS, ORGANIC. Flammable when exposed to heat or flame. Can react vigorously with oxidizing materials. When heated to decomposition or on contact with acid or acid fumes it emits highly toxic fumes of mercury. 

Eldefrawi ME, Mansour N, Eldefrawi A. 1977. Interactions of acetylcholine receptors with organic mercury compounds Membrane toxicity. Proceedings of the 9th Annual Rochester International Conference on Environmental Toxicity. Adv Exp Med Biol 84 449-463. 

There is a vast range of aqueous organic pollutants with a wide toxicity profile. Some, e.g. polychlorinated biphenyls, certain herbicides, fungicides and pesticides, and organo-mercury compounds, are persistent and may bioaccumulate in the food chain. Trace contaminants such as sodium chloride, iron and phenols (especially if chlorinated) may also impart a taste to water. Typical consent levels for industrial discharges are provided in Table 13.10. 

The interest in mercury contamination, and particularly in the organic mercury compounds, is a direct reflection of the toxicity of these compounds to man. Some idea of the proliferation of work can be derived from the reviews of Krenkel [25], Robinson and Scott [26] (460 references), and Uthe and Armstrong [27] (283 references). 

Organic mercury compounds have also been used in latex paint to extend the shelf life, though such uses are currently restricted in the United States following the recognition of this potential hazard to children. Subsequent evaluation of interior rooms of homes painted with mercury-containing latex paint found that mercury vapor concentrations were elevated and in several cases were above the 0.5 pg/m3 concentration recommended by the Agency for Toxic Substances and Disease Registry. 

There are several different types of organic mercury, but by far the most important in terms of health effects is methyl mercury. When atmospheric mercury is deposited on the ground or in the water, it is converted to methyl mercury by bacteria. Mercury compounds are very toxic and this is the bacteria s way to detoxify mercury. Small animals then consume the bacteria, along with the methyl mercury and bigger animals in turn consume the smaller animals, thus increasing the concentrations of methyl mercury. Methyl mercury accumulates in the larger carnivorous animals, most important of which are fish such as tuna, pike, and shark. 

Mercury may be present in air in different chemical states such as the elemental form (as a vapour or adsorbed on particular matter) or in the form of volatile mercury compounds (mercury chloride, methyl-mercuric chloride, and dimethyl mercury). Although elemental mercury is only one of the mercury forms which is not as toxic as its organic or ionic forms, analytical determination of elemental mercury is of special importance. Such analysis is used not only for determination of elemental mercury in environment, but also as a method for determination of other forms of mercury after reductive treatment. 

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