Canada ‘still has a long way to go’ in effective control of acid rain

montreal

Large areas of North America will have to cut sulphur dioxide emissions by an additional three-quarters if they are to control acid rain — a problem many believed to be a thing of the past.

A report published last month by the Acidifying Emissions Task Group, set up by the Canadian government, concludes that this extra cut in emissions is needed in the Canadian provinces of Ontario and Quebec and in midwest and eastern parts of the United States.

The task group, made up of representatives of government, industry and environmental and health groups, was responding to a 1994 request from Canadian environment and energy ministers for a strategy to mitigate the environmental and health effects of acid rain.

“The assumption has been that the problem is solved,” says Wayne Draper, a senior official in the federal environment department who acts as joint chairman of the group. “In reality, we took only a first step and we still have a long way to go.”

That first step, however, has already halved sulphur dioxide (SO₂) emissions in seven eastern provinces. Begun in 1985, the Eastern Canada Acid Rain Program's goal was to reduce wet sulphate deposition to no more than 20 kg per hectare per year. A smaller Sulphur Oxide Management Area in the southeast was to cap SO₂emissions at 1.75 million tonnes a year starting in 2000. Last year, emissions were already 29 per cent below that cap.

The United States has cut emissions by 30 per cent since 1980, and by 2010, when its acid rain programme is fully implemented, emissions should be down by 40 per cent. But this will still leave US emissions about five times greater than those from Canada and responsible for more than half the total acid deposition in eastern Canada.

“Even in 2010, with full implementation of the Canadian and US programs, almost 800,000 square kilometres in southeastern Canada — an area the size of France and the United Kingdom combined — will receive harmful levels of acid rain; that is, levels above critical load limits for aquatic systems,” says the report, Towards a National Acid Rain Strategy.

Tests show that, while sulphate levels are declining in most lakes in Ontario and Quebec and are stable in the Atlantic region, acidity levels remain high. Only 33 per cent of 202 lakes tested in Ontario, Quebec, Nova Scotia and Newfoundland between the early 1980s and the mid-1990s contained less acid, 11 per cent had more and 56 per cent showed the same levels.

“Acidified lakes pose a serious threat to biodiversity in eastern Canada,” says the report. “Loons do not breed as easily or lay as many eggs, and there are fewer species of clams and crayfish — an integral part of the food chain.”

The group recommends negotiating with the United States for further reductions, and reviewing related science, research and monitoring programmes. The report will go to a meeting of energy and environment ministers later this month, who will try to propose a national acid rain strategy.