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New Information Released about Fluoride

Today, both the Environmental Protection Agency (EPA) and the Centers for Disease Control and Prevention (CDC) have released new information related to fluoride, covering both the beneficial levels needed to protect against tooth decay, and the possible risks of fluoride at higher concentrations.  EPA has released a new quantitative dose response assessment and an environmental exposure assessment for fluoride.  At the same time, CDC has proposed an adjustment to the recommendation for the optimal fluoride level in drinking water for good dental health.

The new EPA assessments of fluoride were undertaken in response to findings of the National Academies of Science (NAS).  At EPA’s request, in 2006 NAS reviewed new data on fluoride and issued a report recommending that EPA update its health and exposure assessments to take into account bone and dental effects and to consider all sources of fluoride. In addition to EPA’s new assessments and the NAS report, CDC also considered current levels of tooth decay and dental fluorosis and fluid consumption across the United States.

EPA established regulations for fluoride ion in drinking water in 1986. A non-enforceable Maximum Contaminant Level Goal (MCLG) and enforceable Maximum Contaminant Level (MCL), both at 4 mg/L, were established to protect against crippling skeletal fluorosis. EPA also established a non-enforceable Secondary Maximum Contaminant Level (SMCL) of 2 mg/L to protect against moderate dental fluorosis (discoloration of the tooth enamel), a cosmetic effect.  CDC’s recommendation for the optimum fluoride level to protect dental health has been in a range from 0.7 to 1.2 mg/l.

Now, EPA has completed and peer-reviewed a quantitative dose-response assessment based on the available data for severe dental fluorosis as recommended by NAS.  Additional research will be necessary to obtain dose-response data amenable to a quantitative risk assessment for Stage II skeletal fluorosis and/or skeletal fractures. The dose-response assessment provides a reference dose based on the critical health effect of pitting of the enamel in severe dental fluorosis.  The new oral RfD is 0.08 mg/kg/day.  EPA has also completed and peer-reviewed a document on environmental exposure of children and adults to fluoride and the relative source contribution (RSC) for water.  The RSC is needed in order to derive the MCLG from the dose-response assessment. EPA will review the new risk assessment of fluoride along with other information (e.g., availability of analytical methods, feasibility of treatment, data on occurrence and exposure) to determine whether it is appropriate to revise the drinking water goal and/or standard.

Concerning dental health, HHS is proposing that community water systems adjust their fluoride content to 0.7 mg/L.  This updated recommendation is based on recent EPA and HHS scientific assessments to balance the benefits of preventing tooth decay while limiting any unwanted health effects.  This 0.7 mg/l level is a proposal and CDC will be taking comments on the change once it is officially published in the Federal Register.   When a new optimum fluoride level is adopted as final, we expect new guidance on how states and drinking water systems can implement the new recommendations. Updated questions and answers are already available at http://www.cdc.gov/fluoridation/fact_sheets/cwf_qa.htm.

All the risk analysis documents, including information on the results of the peer review process, are posted on EPA’s website at: http://water.epa.gov/action/advisories/drinking/fluoride_index.cfm.  Specific information on the latest evaluation of fluoride used to determine the new dental health recommendation can be found in the prepublication version of the Federal Register notice at http://www.hhs.gov/news/press/2011pres/01/pre_pub_frn_fluoride.html.  More general information on fluoride for improving dental health can be found on the CDC website at http://www.cdc.gov/fluoridation/index.htm.

ADSWA will keep states informed about EPA’s decision making process, CDC’s proposal on optimum fluoride levels, and any other new fluoride information.