One day in 1986, a running water plant was set up in a village located in Xinbin county, northeast China, and the water was extracted from a well of 73 meters deep.

10 years after, children over 6 years old started to developed strange illness. Their teeth turned yellow and began to peel off, and they often felt pain at their backs and legs. Some adults also got pains on their legs, arms or backs.

In the county dental hospital, the children were diagnosed as fluorosis toxicosis. The cause is the water from that deep well transported through the running water plant. The sample test found that the content of fluorosis in the water is 5 mg per liter, five times the state standard for the drinking water...