Metals pollute water and they do more than affecting wild life. They pass through the food chain from plants or fishes to man and mamals. Minamata disease is an example of the effect of such pollution. Japan is a country highly developed and far advanced in industry. In Japan there is an industrial area on the Minamata Bay in the Pacific Ocean. The bay abounds in fish and so cats were numerous in that area. In 1993 a good number of cats fell dead after they had consumer fishes produced in Minamata bay. Besides hundreds of people also fel ill after eating fish caught in the bay. Not less than 78 persons died after eating fish caught in the bay.
After investigation it was found that the effluents discharged from a certain industry located on the bay contained a relatively high amount of mercury. That high amount of mercury contaminated the sea water in that region. Mercury got into the body of the fishes through food chain. The cats and human beings who ate those fishes contacted mercury poisoning. Mercury attacks the body and the brain and kills the victims. This unusual disease is known as Minamata disease.