ELEMENTAL AND INORGANIC MERCURY-POISONING

Mercury exists as elemental mercury (liquid mercury or mercury vapor), inorganic mercury salts (mercurous or mercuric), and organic mercury compounds (aryl- or alkyl-mercury). Due to the different chemical and physiological properties of all forms of mercury the effects of mercur y on humans shows quite different clinical pictures. In this paper, me rcury vapor and inorganic mercury poisoning are mainly reviewed. Liqui d mercury, since it is poorly absorbed from the gastrointestinal tract , is nontoxic. Mercury vapor (Hg-o) is absorbed rapidly from the alveo lar membrane by inhalation and is accumulated mainly in the brain and kidney. In acute exposure to high concentrations of mercury vapor, the symptoms of respiratory, such as chest pain, cough, hemoptysis, and i nterstitial pneumonitis occur shortly after inhalation. In chronic exp osure to relatively low concentrations of mercury vapor, neurological changes are prominent. The signs and symptoms of mercury vapor poisoni ng is characterized by gingivitis, intentional tremor and erethism, an d in addition, weakness, fatigue, loss of weight, and disturbance of g astrointestinal functions appear unspecifically. Effects of inorganic mercury toxicity manifest in the gastrointestinal tract and kidney aft er ingestion. Early signs and symptoms appear as pharyngitis, dysphagi a, abdominal pain, nausea and vomiting, and bloody diarrhea. Afterward renal failure due to necrosis of the proximal tubular epithelium occu rs and develops into anuria and uremia. The occurrences of mercury vap or poisoning due to occupational or accidental exposures and inorganic mercury poisoning due to accidental or suicidal ingestion are reducin g today in Japan.