Case study

Lesson 16: Water pollution

Case study

A crippling deformity called Minamata disease, caused due to consumption of fish captured from mercury contaminated Minamata Bay in Japan, was detected in 1952. Water contaminated with cadmium can cause itai itai disease also called ouch – ouch disease (a painful disease of bones and joints) and cancer of lungs and liver. The compounds of lead cause anemia, headache, loss of muscle power and bluish line around the gum.


Most of the ground water and the surface water in our country are contaminated with fluoride ions. High concentrations of fluoride ions are present in drinking water in 13 states in India. It has been found that the maximum level of fluoride, which the human body can tolerate is 1.5 parts per million (mg/l of water). Ingestion of fluoride ions for a long time causes Fluorosis. It results in various neuro – muscular disorders leading to crippling of people. In animals, ingestion of fluoride ions causes disorders of bones and teeth and swelling of knee bones.

Last modified: Friday, 30 December 2011, 12:10 PM