The organization representing Canada's environment ministers is considering ordering coal-fired power plants to cut mercury emissions as much as 90 per cent because of concern about learning disabilities in children.
Environmentalists see the proposal as a major development and say it could force some utilities to close their coal plants and convert them to cleaner fuels.
"I think it's very significant that they are considering such a large reduction," said Keith Stewart, an air-pollution expert at the Toronto Environmental Alliance. "It would have implications right across the country."
A notice outlining the proposed reduction, which would apply to all of the country's coal-fired plants and wasn't accompanied by a cost estimate, was released earlier this week by the Canadian Council of Ministers of the Environment and posted on its Web site.
It would require coal-fired stations — primarily located in Ontario, Alberta, Saskatchewan, Nova Scotia and New Brunswick — to have plans in place by 2005 to cut their emissions. The actual reduction would not have to be achieved until 2010.
The mercury proposal has been highly controversial within the electricity business and has been under development for five years.
Canada's power utilities dumped approximately 2,450 kilograms of mercury into the environment in 1999, and the stations are the country's largest remaining human source of mercury emissions, according to the CCME.
The CCME, a Winnipeg-based umbrella group for Canada's federal, provincial and territorial environment ministers, said it made the proposal for fear that mercury, a potent nervous-system poison, is reaching dangerous levels in fish exposed to power-station fallout.
"Human exposure to mercury — primarily by eating contaminated fish — may cause neurological and developmental damage. Low exposure to mercury may cause problems such as learning disabilities in children," it said.
The most vulnerable to mercury are women of childbearing age, pregnant women, children and those, such as natives and avid anglers, who depend on fish for a large part of their food supply.
Other common symptoms of low-level mercury exposure are attention and language deficits, impaired memory and impaired vision.
The CCME said that mercury is causing reproductive failure among loons and river otters, two species that rely heavily on fish in their diet.
Ian Smith, chairman of the CCME committee that drafted the mercury proposal, said international research indicates that children who consume high amounts of fish containing mercury have developmental problems. "Those studies suggest that mercury in high doses can be a problem for kids," Mr. Smith said.
He said there is no specific Canadian research on the effect of mercury on children, but he said officials don't want to take any chances and are recommending large emission reductions as a precautionary measure.
Ontario Power Generation, the largest coal-fired station operator, is studying the recommendations. Spokesman John Earl said it is too early to assess the possible financial impact of mercury controls on the company.
Some environmentalists were critical of the ministers for not moving more quickly to introduce binding limits.
In the United States, mercury controls for power stations are supposed to be implemented by 2008. "I find them slow. . . . We're not leading," said Ken Ogilvie, executive director of Pollution Probe, a Toronto-based environmental group.
The ministers said in their proposal that they want "to explore the national capture of mercury from coal burning in the range of 60 per cent to 90 per cent."
Mr. Ogilvie said equipment already exists that could achieve the 90-per-cent reduction, so there is no need for the ministers to set a lower amount.
Trace amounts of mercury are naturally present in coal, and the metal goes up the smokestack and into the environment when the fuel is burned.
This mercury eventually falls in precipitation into waterways, where bacteria convert it into methyl mercury, a compound readily accumulated by fish at levels that make them dangerous to eat.
Mercury has reached elevated levels in some sports fish in almost all areas of Canada, prompting health authorities to issue numerous advisories warning anglers to eat some species only in limited amounts or stop eating them entirely.
Fish consumption advisories exist for lakes and rivers in Nova Scotia, New Brunswick, Quebec, Ontario, Manitoba, Saskatchewan, Alberta, British Columbia and the three territories.
The environment ministers have previously set regulations to reduce discharges of mercury from base metal mines, fluorescent light bulbs and dental offices, where the metal is used in fillings.
