Fluoride in Drinking Water: How Safe Is It?

Yesterday, the Marquette Water Filtration Plant opened its doors for public tours as part of a program sponsored by the Peter White Public Library.  A small group of curious residents attended (this writer included) and were treated to an overview of the facility and its operations.

Marquette, Michigan is fortunate in being able to draw its drinking water from the cold, clear waters of Lake Superior.  With an intake positioned away from river outlets and outside of the harbor, it pulls water from a depth of 60 feet at a distance of 600 feet from the shore.

This natural advantage, plus an innovative micro-filtration process, means that very few of the EPA’s “regulated contaminants” for drinking water are detectable, and none are in violation of EPA standards.  One of those few detectable “contaminants” is fluoride, a controversial drinking water additive that is purported to reduce rates of tooth decay.

Map showing cases of fluoride and uranium in drinking water in the western Upper Peninsula of Michigan; Photo courtesy Western Upper Peninsula Health Department

Fluoridation of drinking water had its beginnings, rather oddly, with a syndrome called Colorado Brown Stain.  As the name suggests, it involved an unpleasant cosmetic effect, first investigated by a young dental student who relocated to Colorado Springs from the East Coast in 1901.  He was shocked to find that almost 90 per cent of locally born children had severely discolored teeth.

It was eventually determined that there were high levels of fluoride in the original drinking water source, and a correlation was noted between fluoride levels and tooth staining in other towns as well.  Even more significant, from a dentist’s standpoint, was the realization that the stained portions of the tooth were resistant to decay.  It was an “aha” moment, and the State of Michigan was the first to take advantage of it.

In 1945, Grand Rapids, Michigan, became the first city in the world to fluoridate its drinking water.  After just 11 years, the director of the National Institute for Dental Research announced that the incidence of cavities for children born after fluoridation was initiated had dropped by 60 per cent.

Marquette began fluoridating its drinking water in 1951 and in 2009, reported a maximum fluoride level of 1.21 ppm.  EPA standards dictate a Maximum Contaminant Level of 4.0, indicating that “bone disease” may occur if this threshold is exceeded.  A secondary standard of 2.0 ppm is recommended to minimize dental fluorosis, or staining of teeth.

According to the National Research Council (NRC), “Fluoride is readily incorporated and accumulates in the bone.”  They also state that moderate enamel fluorosis will occur in 15 per cent of children in communities where levels of fluoride in drinking water are at or near 2 mg/L.

The NRC, in “Fluoride in Drinking Water: A Scientific Review of EPA’s Standards,” states that “Relative to their body weight, infants and young children are exposed to three to four times as much fluoride as adults.”  And according to the European Food Safety Authority, infants retain as much as 90% of the absorbed amount in their bones, compared to 50% or less for adults.

There are other possible sources of fluoride intake besides drinking water additives—dental products, for instance, which are notoriously difficult for a young child to rinse out.  Fluoride also occurs naturally in the environment.  Michigan’s Western Upper Peninsula Health Department publishes a Fluoride Advisory on their website, citing elevated levels in Houghton and Keweenaw Counties, with some wells testing at levels between 4.0 and 10.3 mg/L.

Interestingly, the Centers for Disease Control and Prevention recommends fluoride levels ranging from 0.7 ppm for warmer climates to 1.2 ppm for cooler climates, suggesting that individuals with a higher water intake are at greater risk.

The World Health Organization cites an ideal range of 0.8 – 1.2 m/L for drinking water supplies, but qualifies that by stating that acceptable levels depend on additional factors such as climate, intake from food sources, and atmospheric concentrations.

During the recent tour of the Marquette Water Filtration Plant, a question was raised as to the appropriateness of fluoridating public drinking water supplies, to which one of the directors responded that local dentists support this practice.  The other rubbed his chin and mused that fluoride was introduced to Marquette drinking water in the 1950’s, and that “longitudinal studies” were supposed to have been done, but they were more like, “five years?”

Indeed, many questions remain as to the safety/efficacy of fluoridation.  Not all filtration systems will remove fluoride.  Boiling will only concentrate it.  Perhaps we shouldn’t be adding it to our water in the first place. Ultimately, it is up to individuals and their communities to decide.

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