Archive for May, 2013

Fluoride and Fish

May 12, 2013

While the early years of the anti-fluoridation movement were dominated by conservative voices, anti-fluoridationists can now be found across the political spectrum. In Portland, OR (which is set to vote on fluoridation this month) the opposition is fairly diverse, coming from both the left, and the right, and well as from some more politically unaffiliated voices. Aside from the usual arguments about “health freedom”, a traditionally right-wing movement that still finds much support in the vegan community, activists in Portland have also been pushing the environmental argument fairly hard, with their central concern being the health of the Columbia River and the salmon populations it supports. Activists have even enlisted the support of some smaller environmental organizations such as the Oregon Sierra Club’s Columbia Group and Columbia Riverkeeper giving their claims an air of credibility.

While I certainly can appreciate a more bio-centric approach to the issue, I still find the arguments put forward by the fluoridation opponents to be unconvincing. To support their claim anti-fluoridationists point to a 1989 study by David M. Damkaer and Douglas B. Dey published in the North American Journal of Fisheries Management that purports to find a safety threshold for salmon exposed to concentrations of fluoride as low as 0.2 ppm. But on closer inspection this study is problematic and does not offer any conclusive evidence. A more recent review from the British Columbia Environmental Protection Division suggested a conservative safety threshold twice that of Damkaer and Dey (0.4ppm). But what does this mean in the context of water fluoridation? How much will the fluoridation of Portland’s public water raise levels in the Columbia River?

Some fluoridation opponents have noted that the expected concentration of fluoride added to Portland’s public water supply will be nearly four times the limit proposed by Damkaer and Dey, and that sewage effluent can exceed this limit even further. However Portland will not be directly fluoridating the Columbia River and despite concerns about run-off, this source is insignificant and is highly diluted by the time it makes it into the Columbia. Nor will Portland simply discharge untreated sewage into the river, that in itself would be a major environmental concern. Waste water is first treated, where around half of the fluoride content may be removed. From there waste water will then be diluted to less than 0.2 ppm fluoride in the mixing zone before heading downstream and diffusing further. A back-of-the-envelope calculation based on the work of John Osterman accounting for flow rate of the Columbia, waste water flow rate, and background fluoride levels shows no more than a 0.00047 ppm change in fluoride concentrations in the river as a result of fluoridation. This is well below any dangerous level for salmon or their prey and would be undetectable against background fluoride levels. A 2004 review of the literature by Howard F. Pollick published in the International Journal of Occupational and Environmental Health offers further support for the pro-fluoridation side, concluding, “[t]here appears to be no concern about the environmental aspects of water fluoridation among those experts who have investigated the matter”.

Further Reading:

Environmental Effects of Fluoridation: City Club of Portland

Why Salmon Have Nothing to Fear from Fluoridation by carmackart

How Some on the Right use Fluoride to Co-opt the Left by carmackart

You Can’t Handle the Tooth: Why the far right and left have come together to defeat fluoride. By Marty Smith

Evaluating the impact of municipal water fluoridation on the aquatic environment.

Tacoma-Pierce County Health Department Fluoridation Resolution Environmental Checklist

City of Port Angeles Municipal Water Fluoridation Environmental Checklist


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