Question

Minamata disease is caused due to the presence of ______ in water.
(a) Cadmium
(b) Lead
(c) Arsenic
(d) Mercury

Answer 1

Hint: Minamata refers to a place in Japan known as the Minamata bay. As this disease originated from a bay, it is caused due to something that was consumed from a marine water body that contained harmful chemicals.

Complete answer:
- Minamata disease is a severe neurological disease caused due to mercury poisoning. It is caused due to the consumption of fish that were once living in mercury-poisoned water.
- The disease was first discovered in 1956 in the Minamata city.
- Symptoms of the disease include the impaired balance due to nerve damage (ataxia), numbness in the hands and feet, general muscle weakness, narrowing of the field of vision, and deterioration of hearing and speech. In extreme cases, insanity, paralysis, coma, and death follow within a few weeks of the onset of symptoms. A congenital form of the disease exists which can also affect fetuses in the womb.
- The water was poisoned due to the release of methylmercury in the industrial wastewater from a chemical factory owned by the Chisso Corporation.
So, the correct answer is ‘Mercury’.

Additional Information:
- The methylmercury bioaccumulate and biomagnify in shellfish and fish in Minamata Bay and the accompanying sea, which, when eaten by the local population, resulted in mercury poisoning in the body.
- Mercury poisoning is a form of heavy metal poisoning. The main metals/metalloids responsible for the poisoning are cadmium, mercury, and lead.
- The routes for entry for heavy metals in the plant, animal, and human tissues are air inhalation, diet, and manual handling.

Note:
- Minamata disease is known as the Chisso-Minamata disease.
- The Chisso corporation was a chemical production company.
- The second outbreak of Minamata disease occurred in Niigata Prefecture in 1965.