Minamata disease, mercury toxicity

A case of Minamata disease caused by the methyl mercury discharged by a chemical factory in Japan provides us with bitter lessons. Inappropriate treatments of toxic chemical substances for the duration of 1932 to 1968 resulted in creating and torturing more than 14,000 victims with a neurological syndrome by severe mercury poisoning. It has been fifty years since the disease was official discovered in 1956. The case is not yet fully solved and lawsuits and claims for compensations continue even to this day. 

Methyl mercury is toxic to humans causing CNS and peripheral nervous system injuries. 13 Those exposed suffer a degeneration of their nervous systems. Symptoms include numbness in lips and limbs, involuntary movement, constricted vision, slurred speech, and hallucinations. The most famous historic example of MeHg poisoning is the Minamata disease outbreak in Japan. 14 ... 

All forms of mercury are considered to be poisonous. However, it is methylmer-cury (or as the chloride, C HgCl) which is considered to be the most toxic because of its ability to bioaccumulate in fish. The best example of the toxicity of methylmercury occurred in Minamata in Japan in 1955. It was found that methylmercury-contaminated fish consumed by pregnant women resulted in the new-born children having severe brain damage (Minamata disease). As a consequence of these initial findings, methylmercury is routinely monitored for in fish. 

It has been stated [11] that about 400 tonnes of mercury lie at the bottom of Minamata Bay near the point of discharge of mercury wastes and although further dumping was finally stopped in 1968, this cannot prevent the future possibility of conversion of inorganic to methyl mercury and its accumulation in fish. By 1973, sixty-five people had died from Minamata disease and many more had been crippled, blinded or otherwise affected. It is now known from experimental work with rabbits, that alkyl mercury can readily pass through the placental barrier in mammals [60] (p. 84) and this is borne out by the fact that a number of children were bom with symptoms of methyl mercury toxicity to women at Minamata who were not evidently themselves affected. 

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