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Fluoride and Salmon

Apr 27, 2013

CRITFC Executive Director Paul Lumley Statement on Portland’s Fluoridation Proposal


The information circulating around Portland’s proposal to fluoridate Portland’s water supply can be overwhelming. Both proponents and opponents are extremely passionate about their perspectives and it is easy to get lost in the debate.

The City of Portland has a responsibility to its citizens to fully understand and thoroughly explain the complete impacts of adding fluoride to its water supply. Voters deserve the opportunity to make an informed decision based on a full review of the impacts to water quality, the aquatic ecosystem, fish populations and the river systems. This proposal could move forward though this review has not occurred.

The City of Portland estimates that 215,000 pounds of fluoride will be added to the water supply each year. The Columbia and Willamette systems are already facing water quality concerns. Adding another component to an already degraded system is a step in the wrong direction.

That is why I am voting No on Ballot Measure 26-151.

Frequently Asked Questions

CRITFC has been asked about its position on the City of Portland’s proposal to add fluoride to the city’s drinking water. CRITFC has explored the potential impacts on salmon populations from the limited amount of available scientific study on this topic, but has not taken an official position.

While the impact on the Columbia River salmon may or may not be minimal, we hope that the fluoridation issue is approached with adequate study and caution. Whatever the outcome of the fluoridation vote, we encourage the City of Portland to always explore the impacts that any of its actions may have on salmonids, lamprey, and other aquatic resources. Portland has a responsibility to the region as the largest city in the Columbia River Basin and with its position near the end of the watershed. Any environmental actions Portland makes has the potential to affect the migration of salmon destined for Oregon, Washington, and Idaho.

This FAQ addresses questions associated with potential impacts of fluoridation to salmon and water quality. It does not address questions related to the efficacy of fluoridating water for the prevention of dental cavities. For those questions, please contact an appropriate health professional.

What is Fluoride?

Inorganic compounds containing the element fluorine are called fluorides. Fluorides can be natural or man-made. Most communities that supplement the fluoride level of their water supplies use fluorosilicic acid, a by-product of fertilizer production. It is this form that Portland would be fluoridating its water if the May 21 ballot initiative passes.

Does fluoride occur naturally in our water?

Yes. Natural fluoride is found in almost all water at some concentration. The natural background concentration of the Columbia River is unknown, as it is uncertain how much impact municipal water systems, industry, agriculture, and other fluoride sources have on the measurements. The USGS reported a 0.12 milligrams/liter (mg/L) fluoride concentration in the Columbia River just downstream of Bonneville Dam. Higher and lower concentrations are found in other rivers and streams throughout the basin.

Does fluoridation of drinking water affect salmon?

We don’t know. Given the widespread practice of adding fluoride to water systems throughout the Columbia River Basin, there is a surprising lack of studies on the effects of fluoride on salmon. One study conducted on fluoride and salmon concluded that a fluoride level of 0.2 mg/L affected migrating salmon behavior while levels above 0.5 mg/L blocked salmon migrating past John Day Dam.

A concern with municipal fluoridation is salmon being affected where municipal wastewater is discharged into a river. A plume containing elevated fluoride levels would be generated where wastewater enters a river. Depending on the size of the river, this plume would dissipate quickly or over a long distance.

If Portland decides to fluoridate its water, how would it affect the fluoride concentration of the Columbia River?

One study estimated fluoridated water from Portland would increase fluoride concentration in the Columbia by an average of 0.00047 mg/L or 470 parts per trillion. Using this scale, the current background fluoride level is 120,000 parts per trillion. During periods of low Columbia River flows this increase would be greater, however even doubling the impact would still result in an increase below what is measurable by current analytical techniques.

Will fish in the Portland area be affected?

We don’t know. There have not been enough studies on the effects of fluoride on salmon and other fishes in the Columbia River Basin to adequately answer this question. In the Portland area, fish are exposed to many pollutants, including those from the Portland Harbor superfund site. With so many chemicals already impacting the capacity of the aquatic ecosystem, it is important to more thoroughly understand not only fluoride’s possible direct effects, but also how fluoride might contribute to the entire toxic burden these fish face. More research is also needed on any potential interactions between chemicals of concern on the ecosystem itself.

version 26 Apr 2013