2011/10/05 Council Agenda Packet

contaminant level (MCL) at a concentration of 4 mg/L or parts per million(ppm).5 The MCL is an enforceable standard. Aside from federal enforcement of the MCL, the level of fluoridation is determined at the local level, generally this practice uses fluoride at approximately 1 ppm. In 1991, the Public Health Service reaffirmed optimal fluoridation of water concentration of 0.7 -1.2 mg/L.6 The NRC, a branch of the National Academy of Sciences, reviewed the health effects of fluoride and found the EPA's MCL of 4 mg/L to be an appropriate interim standard,but further research regarding exposure and toxicity were recommended in 1993.7 2006 NRC Report: Fluoride in Drinking Water: The major conclusion of the 507- page NRC Scientific Review of EPA's Standards is relevant to the entire population (page 2 paragraph 4), "After reviewing the collective evidence, including studies conducted since the early 1990s, the committee concluded unanimously that the present MCLG of 4 mg/L for fluoride should be lowered." The potential health risks are skeletal fluorosis,bone fractures and severe enamel fluorosis, which may increase the risk of dental decay. Another conclusion is important for individuals with chronic kidney disease (CKD),page 9,paragraph 1, "However, a potentially susceptible subpopulation comprises individuals with renal impairments who retain more fluoride than healthy people do." The EPA is evaluating how to best implement the fmdings of this report. Note that reduction of the MCLG of 4 ppm would not affect the practice of fluoridation of water at approximately 1 ppm. Fluoride Health Benefits: The major benefit of water and dental products containing fluoride is the prevention of dental caries in people of all ages. This has been recognized by the US Public Health Service since at least 1950. The Centers for Disease Control and Prevention, the World Health Organization and other respected health organizations also promote water fluoridation. Increasing the proportion of the U.S. populations served by community water systems with optimally fluoridated water is a goal of Healthy People 2010.8 Mechanisms through which fluoride provides this benefit include a systemic effect due to the replacement of hydroxyl ions in hydroxapatite by fluoride ions during tooth development in children during enamel formation, a topical effect to remineralize teeth after bacterial demineralization, and a topical effect to inhibit bacterial acid release.9"° Fluoride Exposure: The major sources of fluoride are water, dental products, and diet. Rarely, drugs and inhalation are significant sources. Approximately 67 % of public US water systems deliver optimally fluoridated water(0.7— 1.2 ppm).11 Soduim fluoride, sodium fluorosilicate, and fluorosilic acid are added to the water systems. Public water systems in the US serving about 1.6 million people have naturally occurring levels that significantly exceed this optimal concentration recommendation. The majority of bottled water,which unlike drinking water is regulated by FDA, contains low levels of fluoride, although there may be significant variation depending on the source. Toothpaste sources contain approximately 1,000 fold more fluoride or 1,000 to 1,500 ppm,which may be a significant source of exposure for individuals with inability to control the swallowing reflex such as children under age 6 years. Of course the level of fluoride in water used to prepare food and beverages will be reflected in the product. Exposure from food and beverages is difficult to monitor, since FDA food labels do not quantify fluoride content.