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Fluoride. It’s good for your teeth and bones! It’s a communist mind control plot! It prevents cavities! It’s highly toxic! These arguments have raged for many, many years over the practice of adding fluoride to drinking water, and will likely rage for many years to come. Fluoride is the (-1) oxidation state of the element fluorine, and if you don’t remember about oxidation states, see the previous article on chromium (VI). It does indeed help prevent cavities by forming an acid resistant coating on your teeth which is less likely to break down in the presence of the acids formed by plaque causing bacteria in your mouth. And it can be toxic in high enough doses; but just like with most things, it’s the dose that makes the poison. A little can be good, too much can be bad. The effects of fluoride on tooth decay were first discovered in the late 1800’s as scientists began researching the cause of the tooth streaking and mottling people get when exposed to high concentrations of naturally occurring fluoride. It was also noticed that in these same areas, the incidence of tooth decay was a great deal lower than the average. It didn’t take long before someone put two and two together, and by about 1945 municipalities started adding fluoride to the drinking water in an attempt to prevent tooth decay. By the early 1950’s, studies had been conducted that showed significant reduction in the number of cavities in those areas where fluoride was being added. And to this day, not a single one of those areas has been over-run by communists! Public health and wellness organizations, such as the American Dental Association and the Centers for Disease Control, still recommend the addition of a small amount of fluoride to drinking water in those areas where it is not naturally occurring. Fluoride has been in the news quite a bit recently in the United States because changes as to the recommendations on the amount of fluoride to be added to drinking water have been proposed. Currently, the U.S. Department of Health and Human Services recommended range is 0.7 mg/L to 1.2 mg/L, but they are proposing to change it to just 0.7 mg/L, making it the same as the current recommendation from the Centers for Disease Control. The EPA is also reviewing the Primary Maximum Contaminant Level (MCL) for fluoride, which is currently 4.0 mg/L, and the Secondary Maximum Contaminant Level (SMCL), which is 2.0 mg/L; California has its own primary MCL of 2.0 mg/L. There is some fluoride in almost all groundwater, but generally it is below the current MCL’s and SMCL’s. However, there are many places in the U.S. where the fluoride levels may be at or slightly exceed 0.7 mg/L. If this level were to become an enforceable standard, then many water systems would have to implement fluoride removal treatment, which can be quite costly.
