North Dakota health officials are allowing the state's water systems to lower fluoride levels in light of a proposed federal rule change for drinking water.
U.S. Health and Human Services is proposing to set its recommendation at 0.7 milligrams per liter of water rather than permitting a range from 0.7 to 1.2 mpl. The change is in response to increased cases of mild fluorosis, or tiny white streaks or specks on teeth, over the past 20 years. Fluorosis is caused by excess fluoride in the tooth-forming years before age 8.
The recommended range for fluoride calls for southern states to be at the lower end of the range. Northern states, such as North Dakota, are advised to use a higher level, between 1 and 1.2 mpl, on the assumption that people in cooler climates drink less water. That assumption no longer is considered valid, said Katie Luther, environmental scientist with the Drinking Water Program in the State Health Department.
Luther said water systems in the state now are being allowed to go to the lower level if they choose, but the health department won't issue any new directive unless the
federal rule changes.
The notice of the proposed change will be published in the Federal Register soon. The Centers for Disease Control and Prevention will accept comments on the proposed recommendation for 30 days at CWFcomments@cdc.gov. Final guidance for community water fluoridation could be released by spring.
The Environmental Protection Agency also is reviewing the amount of naturally-occurring fluoride that it will continue to allow in drinking water.
North Dakota health officials say they are unaware of dental fluorosis in the state related to fluoridated drinking water. About 95 percent of the state's population is served by a fluoridated water supply.
"I don't think there is any cause for alarm," said Minot dentist Murray Greer, a board member of the North Dakota Dental Association's northwest district organization. He said he has seen very few problems related to excess fluoride in nearly 25 years, and problems that occur usually result from high levels of naturally occurring fluoride in water in rural areas.
He agrees with the American Dental Association, which supports a lower fluoride level but maintains the importance of fluoride in public drinking water.
"It has proven to be a very effective means of reducing tooth decay. It's been shown over and over," Greer said.
Although there is no legal requirement to fluoridate water, the City of Minot has used fluoride for more than 55 years, said Jason Sorenson, water treatment plant superintendent. Sorenson said the city hasn't received notice of any proposed change and is continuing to fluoridate at 1 to 1.2 mpl.
Once added to the water, fluoride does not dissipate in distribution. Users who access Minot's water include Minot Air Force Base, North Prairie Rural Water and Northwest Area Water Supply communities, including Kenmare, Burlington and Berthold.
Bottled water may contain fluoride, even if not labeled. Most home water purification systems don't remove fluoride. Reverse osmosis and distillation are the best removal methods, although dental groups say that within the federal limit, fluoridation is safe and doesn't need to be removed.
Water fluoridation is credited with reducing tooth decay by 20 to 40 percent, even with other sources of fluoride available through toothpastes and mouth rinses.