Impact of Artificial Fluoridation on Salmon in the Northwest US and British Columbia
Foulkes, Richard G., Anderson, Anne C., Earth Island Journal
In the US Northwest, species of salmon using the Snake-Columbia River system, are listed as "endangered." On the North Thompson River of British Columbia, Canada, sperm banks are being employed to preserve salmon species. Proposed water diversion on the Nechako River, in British Columbia, may threaten the internationally important Fraser River fishery.
Writing in the quarterly magazine, The New Pacific, in January 1994, Joseph Cone reported that the annual migration of salmon in the Snake-Columbia River system had declined over the past century from an estimated 10-16 million to 2 million in 1991. He pointed out that "the problem is enormously complex -- biologically, administratively and economically." His article and reports in the media have stressed problems with harvesting; loss of habitat through poor forestry practices, livestock and human settlement; and dams built for power and irrigation. Little emphasis is placed on the effects of pollution of water by toxic substances such as fluoride.
The aluminum industry is the chief beneficiary of power dams on the Columbia River System, and it is the fluoride wastes from smelters that first come to mind as sources of fluoride pollution. However, there is another potential source of contamination -- the artificial fluoridation of community water supplies for the avowed purpose of improving dental health.
Fluoride and "Critical Habitat"
In discussions of "critical habitat" for endangered salmon species, all of the possible components must be evaluated. This study examines the possibility that artificial fluoridation of drinking water in communities along the course of salmon rivers is a factor to be included.
The US Environmental Protection Agency (EPA) and the Province of British Columbia adhere to a "permissible level" of 1.5 ppm (1.5 mg/L) for fluoride discharged into fresh water. BC's "recommended guideline" is currently 0.2 ppm fluoride; but this does not have the force of legislation. Neither the Minister of the Environment nor the Washington State Department of Ecology requires fluoride estimations for sewer effluent permits as it is considered fluoride is not significantly toxic to aquatic life in concentrations expected in discharges.[3,4]
A review of the literature and other documents, including as court transcripts, reveals that levels below 1.5 ppm have been shown to have both lethal and other adverse effects on salmon. Evidence presented by the EPA and other government bodies responsible for the environment suggests that harm can come to aquatic life only at concentrations that far exceed those in discharges from fluoridated cities. Both Groth and Warrington point out that many factors influence susceptibility of fish to fluoride: temperature; water hardness; pH; chloride concentration; and, the strain, age and physiological and reproductive condition of the fish.
Groth points out that there are serious problems with laboratory experiments as opposed to field studies. In lab tests, "... many of the organisms tested for fluoride toxicity did not experience effects until levels of fluoride higher than those which might realistically be encountered in the environment were attained." Groth concluded that the finding can be misleading: the techniques of measurement may be inadequate to detect effects, and these may be at the population rather than individual level.
There are studies showing the effect of water temperature and hardness. Angelovic and others showed lethal effects on rainbow trout related to temperature. Using sodium fluoride at the same degree of hardness (estimated at 44 by Warrington), at 7.2 degrees C over an exposure period of 240 hours, Angelovic determined that the LC50 (the lethal concentration required to kill 50% of the tests subjects) was 5.9-7.5 ppm. At 12.8 degrees C, half the trout died at concentrations of 2.6-6.0 ppm. Neuhold reported the same result for 12. …