Mercury, toxicity

AppHcations of mercury include use in batteries (qv), chlorine and caustic soda manufacture (see Alkali and chlorine products), pigments (see Pigments, inorganic), light switches, electric lighting, thermostats, dental repair (see Dental materials), and preservative formulations for paints (qv) (1—3). As of the end of the twentieth century, however, increased awareness of and concern for mercury toxicity has resulted in both voluntary and regulatory reduction of mercury usage (see also Mercury compounds). 

Production and use of mercury is expected to continue to decrease, owing to mercury toxicity. Many of the traditional uses have either declined or have been eliminated (14). 

Prior to the 1990s phenyhnercuric acetate was the primary bactericide and fungicide in latex and waterborne paints. Because of the increasing concerns of mercury toxicity and the potential for high consumer and occupational exposures to mercury when present in paints, the U.S. Environmental Protection Agency (EPA) induced U.S. manufacturers of PMA and other mercury compounds to withdraw their registrations for use of these substances as biocides in paints (see AIercury). Mercury compounds are used only for very limited, specific purposes, such as the use of phenyhnercuric mXx.2LX.e[55-68-5] as a bactericide in cosmetic eye preparations (see Cosmetics). 

Current work directed at elucidating the mechanism of mercury toxicity will be a fertile area of research into potential sub-organismal biomarkers. Techniques including... 

Loerzel SM, Samuelson DA, Sepulveda MS, Spalding MG, Lewis P, Smith PJ. 1996. Initial evaluation of mercury toxicity in the eye of the great egret. Investig Ophthalmol Vis Sci 37 s349. 

J. Royhans, P. Walson, G. Wood, and W. MacDonald, Mercury toxicity following merthiolate ear irrigations, J. Pediatr., 104, 311 (1984). 

Exposure to Hg may cause serious harm to human health, at high doses it can even be fatal. Mercury toxicity usually involves the kidneys and/or nervous system disorders (central nervous system and neurobehavioral changes). Mercury contamination has been found in more than 70 federal sites with Hg-contaminated wastes. 

Khera, K.S. 1979. Teratogenic and genetic effects of mercury toxicity. Pages 501-518 in J.O. Nriagu (ed.). The Biogeochemistry of Mercury in the Environment. Elsevier/North-Holland Biomedical Press, NY. 

Niimi, A.J. and G.P. Kissoon. 1994. Evaluation of the critical body burden concept based on inorganic and organic mercury toxicity to rainbow trout (Oncorhynchus mykiss). Arch. Environ. Contam. Toxicol. 26 169-178. 

Rosenman KD et al Sensitive indicators of inorganic mercury toxicity. Arch Environ Health 41 208-215, 1986... 

Ban M, de Ceaurriz J. 1988. Probenecid-induced protection against acute hexachloro-1,3-butadiene and methyl mercury toxicity to the mouse kidney. Toxicol Lett 40 71-76. 

In spite of these limitations it is possible to obtain valuable data provided specific questions are posed. For example, it has been suggested that the level of methyl-mercury in a sample is a good indicator of the level of mercury toxicity Therefore it will be most useful to detect and quantify this species rather than to use the available resources to detect a wide range of mercury species, whose biological behaviour are yet to be established. It is essential to clearly define the purpose and use to which the information will be put before any speciation experiments are performed. This helps not only in the choice of the appropriate techniques and methods, but also helps to focus attention on the parameters that are useful for the interpretation of the results. 

As dangerous as mercur r vapor is, it is by no means the most toxic form of the metal. This distinction belongs to a compound of mercury, dimethyl mercury. The world found out about the deadly nature of this substance in the 1950s, when dozens of people died and thousands experienced symptoms of mercury toxicity in the Japanese fishing village of Minamata. A nearby chemical company had been using mercury in the production of acetylene, and it had routinely discharged the used mercury into the ocean. Mercury isn t soluble in water, and it should have simply accumulated harmlessly at the bottom of the sea. But it didn t. 

Toxicity. The toxic el frets of mercury and mercury compounds are well known, and several detailed discussions on mercury toxicity are available. Toxicity lo the central nervous system is more prominent aftci exposure lo mercury vapor than lo divalent mercury. 

Alberts, J.J., Takacs, M. and Pattanayek, M. (2001) Influence of IEfSS standard and reference materials on copper and mercury toxicity to Vibrio fischeri, Acta Hydrochimica et Hydrobiologica 28, 428-435. 

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