Question:
The U.S. Environmental Protection Agency's standard for the maximum amount of fluoride allowed in drinking water -- 4 milligrams of fluoride per liter of water is that right ?

Answer: The U.S. Environmental Protection Agency's standard for the maximum amount of fluoride allowed in drinking water -- 4 milligrams of fluoride per liter of water -- does not protect against adverse health effects, says a new report from the National Academies' National Research Council. According to the most recent data, just over 200,000 Americans have drinking water sources containing fluoride levels at 4 mg/L or higher. The committee that wrote the report concluded that children exposed to the current maximum allowable concentration risk developing severe tooth enamel fluorosis, a condition characterized by discoloration, enamel loss, and pitting of the teeth. A majority of the committee also concluded that people who consume water containing that much fluoride over a lifetime are likely at increased risk for bone fractures.

The report does not examine the health risks or benefits of the artificially fluoridated water that millions of Americans drink, which contains 0.7 to 1.2 mg/L of fluoride. Although many municipalities add fluoride to drinking water for dental health purposes, certain communities' water supplies or individual wells contain higher amounts of naturally occurring fluoride; industrial pollution can also contribute to fluoride levels in water. Because high amounts of fluoride can be toxic, EPA places a cap, or maximum contaminant level, on fluoride concentrations in drinking water in order to prevent adverse health effects.