Mercury: A toxic poison Essay -- Chemistry Metal Papers

Mercury: A toxic poison No other metal better illustrates the diversity of effects caused by different chemical species than does mercury. On the basis of chemical speciation, there are three forms of mercury: elemental, inorganic, and organic compounds. The major source of mercury is the natural degassing of the earth's crust, including land areas, rivers, and the ocean, and this source is estimated to produce on the order of 2700 to 6000 tons per year. The total man made release into the atmosphere is about 2000 to 3000 tons, and it is difficult to assess what quantities of mercury come from human activities and what quantities from natural resources. Run-off into natural bodies of water may contain mercury from both anthropogenic and natural sources, so it is difficult to assess how much released into the atmosphere is from man made or natural sources. Nevertheless, mining, smelting, and industrial discharge have been factors in the environmental contamination in the past. For instance, it is estimated that loss in water effluent from chloralkali plants, one of the largest users of mercury, has been reduced to 99% in recent years. Industrial activities not directly employing mercury or mercury products give rise t o substantial quantities of this metal. Fossil fuel may contain as much as 1 ppm of mercury, and it is estimated that about 5000 tons of mercury per year may be emitted from burning coal, natural gas, and from the refining of petroleum products. Calculations based on the mercury content of the Greenland ice cap show an increase from the year 1900 to the present and suggest that the increment is related both to an increase in background levels of mercury in rainwater and to man made r... ...lbut, K.M., FASEB 1992, 6, 2472-2476. 19.Boyd, N.D., Benediktsson, H., Hooper, D.E., Vimy, M.J., American J. Physiology 1991, 261, R1010-R1014. 20.Molin, M. Bergman, B., Marklund, S.L., Schutz, A. Acta Odontol. Scand., 1990, 48, 89-202. 21.Summers, A.O., Wireman, J., Marshall, B., Antimicrob. Agents & Chemotheraoy, 1993, 37, 825-834. 22.Gilbert, M.P. and Summers, A.O., Plasmid, 1988, 20: 127-136. 23.Intercontinental Medical Statistics, Canada, 1992. 24.Cohen, M.L., Science, 1992, 257, 1050-1055. 25.Thompson, C.M., Markesbery, W.R., Ehmann, W.D., Vance D.E., Nerotoxicology, 1988, 9, 1-7. 26.Palkiewicz, P., Zwiers, H., Nuerochem. 1994, 62, 2049-2052. 27.Lundstrom, I.M.C., Int. J. Oral Surgery, 1983, 12, 1-9. 28.Austrian Minister of health, Austria to be amalgam free by the year 2000. FDI Dental World, March/April, 1993, page 6.