Environment : It May Be Time for Some Good News About Acid Rain : The Earth still has a long way to go. But in one area--the U.S.-Canadian border--the pending American clean-air law has even Canada’s environmentalists sounding hopeful.

This is one of those all-too-rare good-news stories about the environment in our industrial age.

The subject: acid rain, a phenomenon plaguing many developed countries of Europe and North America, and a particular sore spot for at least a decade in relations between Canada and the United States.

Canadians believe that about 7,000 lakes in Ontario province alone have become so acidic, largely from U.S. pollution sources, that most of the fish in them have died. Other studies--not all of them conclusive--suggest that acid rain is shrinking the eastern Canadian duck population, killing off vast swathes of maple trees and turning proud marble edifices into spongy masses that can be sliced with a knife.

Tourism officials have complained bitterly that in killing the fish, acid rain is also strangling one of the few successful industries in rocky and undeveloped north-central Canada.

Acidic lakes look unnaturally lovely--”like your average swimming pool, aquamarine blue and clear,” says Michael Perley, secretary-treasurer of the Canadian Coalition on Acid Rain. But tourists come to this part of Canada to fish, not to admire blue waters. And the reason the lakes look so crystalline is that nothing can live in them. “If you snorkel in one, there’s nothing but a mat of filamentous algae on the bottom,” says Perley. “At a quick glance, it sort of looks like Astroturf.”

Research on hospitalizations in southern Ontario show that more people are treated for emphysema, bronchitis, pneumonia and other respiratory problems during the summer acid rain season than at other times of the year.

Despite such hazards, Canadians say, the United States has resisted pressure to take corrective action for a decade.

Now, however, even some of this country’s most outspoken environmental critics have changed their tune.

“I think that this is going to be the year for acid rain control in the United States,” says Perley, whose group has done more than any other to channel this country’s exasperation with the United States.

Perley and others base their optimism on pollution control measures that would be required under the U.S. Senate’s version of the Clean Air Act, which is expected to become law this summer.

The provisions would mean that the flow of acid rain-causing emissions into Canada would be cut in half by the turn of the century--enough of a change that most of this country’s acidic lakes could naturally revert to their pristine state within five to 10 years.

“The lakes will improve spontaneously,” says Peter Dillon, manager of the Ontario Ministry of the Environment’s aquatics research center in Dorset. “The chemistry will revert to its original state, and the biological organisms will follow suit, more slowly.”

All it takes, he says, is for the polluters to reduce their emission levels, and the process will start.

“The movement on acid rain is encouraging,” agrees Derek Burney, Canada’s ambassador to the United States. “It can’t help but add an element of productivity” to U.S.-Canadian relations, he said.

Back in the 1980s, he explains, Canadian Prime Minister Brian Mulroney and former President Ronald Reagan spent much of the time they were together mired in unproductive haggling over acid rain. With the dispute poised to become history, he said, Mulroney and President Bush will have more time to focus on broader issues.

Canadians credit their own intensive lobbying, growing understanding of the problem and dramatic differences in outlook between the Bush and Reagan White Houses. And while optimistic, they stress that more can still be done.

Even after most of Canada’s dead lakes revive, they say, one-third or more of them will still be dangerously acidic.

“We’ll still be pushing for even more emission controls in the future,” says Dillon. “We want more than two-thirds of the lakes to recover. We’d like to be up in the neighborhood of 95%.”

Still, he says, the outlook is vastly better than it was not long ago, when Canadians feared it would take 40 years before their waters could sustain fish again.

Until 1986, Canadians were putting all their hopes into dumping crushed limestone--which neutralizes acid just like an enormous dose of Rolaids--into their lakes. But experiments showed that the cost was impossibly high: $80,000 for a medium-sized lake. Thousands of lakes needed treatment, and the process would have to be repeated every few years.

Canadians have been worrying about acid rain since the 1970s. And early on, they had American support. Scientists in both countries knew that a number of lakes on both sides of the border were becoming too acidic to sustain life, and they believed there was a connection between the acidity and the burning of fossil fuels.

The scientists didn’t understand the link fully, but even so, then-President Jimmy Carter’s Environmental Protection Agency was concerned enough to sign a memorandum of understanding with Canada, appoint technical experts and begin negotiating an acid-rain treaty.

The process went off track with Carter’s loss to Reagan in 1980, however. Reagan’s EPA appointed new acid-rain negotiators, and government attention turned from environmentalism to economics. With so much uncertainty about the causes of acid rain, the new technicians said, it would be a mistake to spend vast sums of money on a cleanup. What if industry were forced to lavish millions on cleanup methods that didn’t work?

The new approach definitely saved money for industry, but it cost the United States dearly in good relations with its northern neighbor.

Reagan-era negotiators did little but go through the motions for a couple of years, said Kai Millyard, policy director of Friends of the Earth in Ottawa. “Then the whole (treaty process) was shut down at the end of 1982,” Millyard adds.

The Americans did have a point, though, when they said there was risk in attacking the problem with a bad solution. Acid rain is itself the result of an earlier attempt to solve the air-pollution woes of America’s rust belt.

Years ago, power plants and factories burning fossil fuels had relatively short smokestacks; the sulfur dioxide they emitted used to hang low over the landscape, rusting cars and ruining house paint. Pressured to solve the problem, the power plants built very tall smokestacks in an effort to shoot the sulfur dioxide high into the atmosphere, where it supposedly would harmlessly disperse.

Instead of dispersing, though, the sulfur dioxide entered the massive weather systems of the upper Midwest and was ferried across the continent for hundreds of miles. At some point, high in the atmosphere, it underwent chemical reactions--this is the stage scientists don’t fully understand--and turned into sulfuric acid. It then came raining or snowing down onto the landscape, far from the source.

Acid precipitation has showered down on both countries, but it does more damage to Canada than to the United States because Canada was glaciated long ago and lacks America’s abundant topsoil. In much of the United States, soils neutralize the acid rainfall so that the runoff going into its lakes does not poison the fish. In vast reaches of Canada, however, the rain falls on granite and run straight into lakes.

In the early part of the 1980s, much of Canada’s acid-rain lobbying was aimed at restarting the treaty negotiations Carter’s EPA had begun. But it failed.

It ultimately took a presidential election, and the inauguration of George Bush, to nudge things off dead center.

“Bush is an outdoors person,” says Casey Padgett, legislative counsel at Environmental Action in Washington. “He is a fisherman. For a Republican, he’s sort of in the Theodore Roosevelt mold. So it’s not surprising that on the environment, acid rain should be the thing he cares about.”

Acid Rain: How it Happens, Why it Kills

1. Sources of oxides: Tall smokestacks spread pollutants high in the atmosphere, where they react with water vapor in clouds to form drops of dilute acid.

2. Oxides form acids in clouds: Sulfur dioxide and nitrogen oxides are products of combustion processes.

3. Winds blow acid-laden clouds: Prevailing winds can carry acid-laden clouds hundreds of miles, until they meet high altitudes or cold air and drop their mosture in acid rain or snow.

4. Acid’s killing effects...:...are intensified when acids are trapped in winter snow, are released in bursts during spring thaw and build up in lakes.

Higher acidity kills algae, leaving lake water clear.

Aluminum, leached from soil by acids, kills fish by causing gills to clog.

Dilute acid from rain and snow concentrates in streams.

Acid lowers pH of soil, killing trees and plants in some areas.