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Fluoride in Drinking Water (March 2006)

Report in Brief

Most people associate fluoride with the practice of intentionally adding fluoride to public drinking-water supplies for the prevention of tooth decay. However, fluoride can also enter public water systems from natural sources, including runoff from weathering of fluoride-containing rocks and soils and leaching from soil into groundwater. Fluoride pollution from various industrial emissions can also contaminate water supplies. In a few areas of the United States, fluoride concentrations in water are much higher than normal, mostly from natural sources. Because it can occur at toxic levels, fluoride is one of the drinking water contaminants regulated by the U.S. Environmental Protection Agency (EPA). In 1986, EPA established a maximum allowable concentration for fluoride in drinking water of 4 milligrams per liter (mg/L), a guideline designed to prevent the public from being exposed to harmful levels of fluoride. After reviewing research on various health effects from exposure to fluoride, including studies conducted in the last 10 years, this report concludes that EPAÂ’s drinking water standard for fluoride does not protect against adverse health effects. Just over 200,000 Americans live in communities where fluoride levels in drinking water are 4 mg/L or higher. Children in those communities are at risk of developing severe tooth enamel fluorosis, a condition that can cause tooth enamel loss and pitting. A majority of the reportÂ’s authoring committee also concluded that people who drink water containing 4 mg/L or more of fluoride over a lifetime are likely at increased risk for bone fractures.