A new report says that the Environmental Protection Agency's current standards for naturally occurring fluoride levels in drinking water -- no more than 4 milligrams per liter of water -- are too high and put people at risk for the adverse health effects caused by excess fluoride.
The report was issued by the National Academies' National Research Council, a nonprofit institution that provides science and health policy advice to the federal government.
The NRC committee concluded unanimously that children exposed to the current maximum fluoride concentration are at risk for developing severe tooth enamel fluorosis, a permanent condition characterized by discoloration, enamel loss and pitting of the teeth. The committee also concluded that cumulative exposure to that level of fluoride can weaken bone and increase the risk of fracture in adults.
The NRC report states that in communities with water fluoride concentrations near 4 milligrams per liter, about 10 percent of children develop severe enamel fluorosis. The rate of severe fluorosis drops to almost zero in communities where the fluoride concentration is 2 milligrams per liter.
According to the committee's report, most of the drinking water in the country has a fluoride level much lower than the EPA's recommended cutoff point. But it's estimated that excessive fluoride levels affect about 200,000 people whose water has fluoride levels of 4 mg/L or higher, and an additional 1.4 million people whose water has 2 mg/L of fluoride, which can lead to such cosmetic side effects as tooth discoloration.
"The report in no way examines or calls into question the safety of community water fluoridation, which is the process of adding fluoride to public water supplies to reach an optimal level of 0.7 to 1.2 milligrams per liter in order to protect people against tooth decay," according to a recent statement from the American Dental Association.
Rather, the research council says the EPA needs to lower its current maximum contaminant level to ensure that optimal fluoride levels are met.
In some areas of the U.S., natural runoff from fluoride-containing rocks can end up in public water systems. South Carolina, Texas, Oklahoma, and Virginia have the largest populations receiving water supplies with greater than 4mg/L of fluoride. Less populated areas with high fluoride levels include Idaho, New Mexico, and Colorado.
"We aren't telling the EPA what the new standard ought to be, but we're recommending that they do the risk assessment ... to set a new level," said Charles Poole, a professor of epidemiology at University of North Carolina and a member of the council's committee.
Dale Kemery, a press officer at the EPA, agrees.
"The agency does have regulatory responsibility over fluoride and will give serious consideration to the NRC's recommendations," Kemery said.
When asked when the changes might take place, Kemery said, "I have no idea at this point because the report is quite new and quite thick -- 400 pages."
Much stricter fluoride standards are recommended by the Environmental Working Group, a nonprofit environmental research organization based in Washington, D.C. It believes that "fluoride exposure should be limited to toothpaste, where it provides the greatest dental benefit and presents the lowest overall health risk."
Environmental Working Group's major concern is infants who are bottle fed with formula reconstituted with tap water.