Fish may not brush their teeth, but they could be dying from fluoride consumption, according to a city conservation group.

The Sierra Club of Canada’s Chinook chapter is so concerned about the levels of fluoride in the city’s waterways, it wants aldermen to impose a moratorium on fluoridation.

Past concerns have focused on perceived threats to human health.

This time, the concern centres on fish. The city adds .7 milligrams of fluoride per litre to its tap water. Many communities in Canada and the U.S. do this to provide dental protection to a large number of people at a low cost.

But some environmentalists want it stopped.

“If at low levels fluoride affects aquatic life like rainbow trout, and things are cumulative up the food chain and humans are affected, why are we putting this in our water?” said Jennifer Wright, spokeswoman for the Chinook chapter of the Sierra Club of Canada.

Wright, citing the 2002 Canadian Drinking Water Quality Guidelines prepared by a federal-provincial committee, said fluoridation of public water supplies causes unnaturally high levels of inorganic fluorides to be released into the soil, air and water.

“Inorganic fluorides affect basic physiological and biochemical processes of fish, plants and other aquatic organisms. Inorganic fluorides can slow growth and development, cause abnormal behaviour and lead to death,” the report said.

Wright wonders: If this is happening to fish, what is happening to humans?

Alberta Environment has set an acceptable maximum level of 2.4 milligrams of fluoride per litre for waterways. Fluorine is a naturally occurring element in aquatic environments.

The Elbow River’s fluoride level has been measured at .3 milligrams per litre, while the Bow River fluctuates from .1 to .3 mg. In Irricana, 60 kilometres northeast of Calgary, the naturally occurring fluoride level is in the range of about 2.3 mg per litre.

The Canadian Dental Association recommends a maximum of 1.5 mg of fluoride per litre of water, but other agencies such as the U.S. Environmental Protection Agency put the maximum recommended level at four milligrams per litre.

Fluoridation of the city’s drinking water began in August 1991, after repeated plebiscites.

Ald. Ric McIver said even though he is against water fluoridation, he would not support a moratorium.

“I don’t like putting chemicals in my body. But as much as I don’t like it, the people I work for want it and they made that known in two plebiscites,” he said.