57.Chart
Transitions in the quantity of chlorine sterilization
In Japan, residual chlorine in water supplies is set at a minimum of 0.1mgs per liter of water.
Since there is no upper limit, though, in Tokyo, for example, it has been fluctuating in the range of three to five times that amount.
58. Illustration
Harmful substances that enter the body
Chlorine combines with organic matter in raw water and generates a carcinogenic substance known as trihalomethane. In addition, it has been shown that accumulations of this substance in the body can cause damage to the central nervous system and to the genes.
59. Water purifier
In the past, water supplies in Japan had a wide reputation around the world for providing "delicious" watera Currently，however，the water in most cities has a bad odor and taste and water purifiers are being used increasingly in households.
