TORONTO - Ontario Premier Dalton McGuinty's claim that elevated levels of radioactive tritium found in the Great Lakes pose no health threat proves he's ignoring his responsibilities to the public, an environmental conference heard Saturday.

"The government's general theme is to duck and dodge and avoid responsibility for (nuclear) issues,'' said Shawn-Patrick Stensil, an energy campaigner with Greenpeace.

Stensil was speaking in Toronto at the annual conference of Great Lakes United, an international collective of environmental lobbyists who want to see the U.S. and Canada take greater action to keep the waterway clean.

A Greenpeace report released last week found that levels of tritium in Lake Ontario, which is flanked by 10 nuclear reactors, were three times higher than levels in Lake Superior, which has no reactors.

The report also criticized Canada for having regulations for tritium concentrations 10 times less strict than those in the U.S. and 70 times less strict than those in Europe.

On the heels of the report's release, McGuinty said he was confident the federal government would take charge if anything was wrong.

Derek Stack, the conference's executive director, said McGuinty's reaction to the study was not surprising given that the Ontario government is heading into an election.

"They're determined to get out a positive, green message,'' he said. "The downplaying there only has to do with politics.''

Ontario's natural resources minister, David Ramsay, said the results warranted further study. "Obviously, I want to look into it more,'' he told The Canadian Press.

Nuclear industry representatives maintain that even the maximum allowable Canadian limit for tritium concentration in water is safe. Jeremy Whitlock, a past president of the Canadian Nuclear Society, said people shouldn't be concerned by the discrepancy between tritium regulations here and those in other countries.

"Regardless of the different regimes, we're talking about levels of radiation where there's been no observed effects,'' he said.

Whitlock said researchers have studied tritium for decades and Canada's levels are safe.

Steve Erwin, a spokesman for Ontario Energy Minister Dwight Duncan, said Ontario Power Generation sets its own concentration standards _ and these are much lower than U.S. regulations.

He said Ontario Power Generation's self-imposed maximum limit for tritium concentrations in nearby water is 100 becquerels per litre, which is seven times less than the American maximum limits.

"Nuclear plants wouldn't be running if we didn't think they were safe,'' said Erwin.

But Stensil and Stack said even if they were convinced the plants were safe in terms of tritium emissions, nuclear power should be phased out. They referenced a number of other issues, from the threat of proliferation to the problem of where to store waste.

On that issue, Stensil took aim at the federal government, which recently announced it would approve plans to dispose of nuclear waste by burying it underground.

He said Ottawa's plan amounts to nothing more than a re-packaging of a similar proposal on the table decades ago.

"All the old problems are still there and we need to remind the government of that,'' he said.

"What community is going to accept dangerous radioactive waste?'' Stensil said, calling the government's plan unfeasible.

Stensil called on governments to abandon commitments to nuclear power in favour of cleaner alternatives.

But the province's natural resources minister said that's not possible because new technologies can't provide a steady baseload and consistent demand for electricity.

"So what we're doing in Ontario is ensuring we have the greatest diversity of energy sources possible,'' said Ramsay, adding that for now, that includes nuclear power plants.