Health and environmental impact of mercury: Past and present experience

Mercury exists in various forms including metallic mercury, inorganic and organic mercury compounds. Research studies show that contamination brought about by natural and man-made activities is clearly a growing problem today. In 1956, the first recognized poisoning outbreaks occurred. Minamata Disease is a disorder of the central nervous system caused by the consumption of fish and shellfish contaminated with methylmercury. Clinical manifestation differs from inorganic mercury poisoning in which the kidneys and the renal system are damaged. The toxidrome consists of sensory disorders in the distal portion of the four extremities, cerebral ataxia, bilateral concentric constriction of the visual field, central disorder of ocular movement, central hearing impairment and disequilibrium. Fetal type Minamata Disease bom of mothers being exposed to methylmercury during pregnancy resulted in conditions similar to those associated with infantile cerebral palsywere also documented. Measures to control environmental pollution were implemented such as the environmental restoration project, compensation and relief of victims as part of the health and environmental management undertaken by the government. At present, global research studies are focusing on long-term and low-dose inorganic and methyl mercury exposure; and developmental neurobehavioral toxicity including relevant environmental factors influencing mercury transformations, mass balances and partitioning in ecosystems.