USA - What's on tap- for and against

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4. Health: Municipal water contains residual amounts of chlorine, which is used to keep the water clean, and many cities add fluoride to promote dental health. A report last year from the National Academy of Sciences cited concerns about bone fractures and a discoloration and weakening of tooth enamel because of high fluoride levels in municipal water. Nitrates can be found in water in rural areas, says Bill Morris, professor of food science and technology at University of Tennessee. Sometimes, he says, when old copper pipes are used, lead can seep into the water. There are also several countries where the water is unsafe to drink..................