Development of Canada's oil sands is spewing dangerous levels of toxic metals like mercury and arsenic into one of the country's main waterways, a new study finds.

The findings contradict previous reports from the Albertan government and industry officials that pollutants in the Athabasca River and its tributaries are naturally occurring and are not a product of industrial operations in Canada. The researchers from two Canadian universities and Oceana, an ocean advocacy group, found that 13 elements classified as priority pollutants by U.S. EPA are flowing through the 765-mile river because of oil sands activity in Alberta.

The peer-reviewed study, published last week in Proceedings of the National Academy of Sciences, comes at a time of increased scrutiny of the province's oil sands, which produce more carbon dioxide emissions than conventional oil. Already, Albertan Premier Ed Stelmach has called for government scientists to work with oil sands critics and discuss the new data.

Unlike conventional oil drilling, Albertan crude, or bitumen, is pulled to the surface by mining or by injecting steam beneath the surface of large sand deposits.

Canadian officials have been on a lobbying campaign in recent months as the U.S. State Department weighs a decision on whether to build a pipeline from Alberta to Texas that would more than double the amount of oil sands crude coming into the United States. Supporters of oil sands development say it is a critical piece in weaning North America from Middle Eastern oil.

Green groups and members of Congress, including Rep. Henry Waxman (D-Calif.), have challenged the pipeline because of the emissions profile and environmental impact of the oil sands.

A 'bull's-eye' of toxins

The study authors concluded that the pollutants in the Athabasca River came from oil sands-related activity, rather than from the natural flow of water passing through metal-rich soil along the riverbank. They reached that conclusion because toxic elements like copper found in the river appeared in greater concentrations near smokestacks processing Albertan oil and close to areas where earth and trees had been uprooted because of oil sands production.

"The pollutants form a bull's-eye in the water around oil sands facilities," said David Schindler, a study co-author and ecologist at the University of Alberta. The six researchers measured the chemical mix at more than 30 locations in both the river in summer and snowpack in the winter.

If the pollutants occurred naturally, they would appear in high concentrations downstream rather than just near industrial facilities, Schindler said.

The academic team reported that levels of seven chemicals in the river, including lead, mercury and zinc, exceeded Canada's guidelines for the protection of aquatic life. Native Canadians in the Athabasca watershed region also have claimed that cancer rates have increased because of the oil sands production in the region, the analysis notes.

All of the pollutants are toxic to humans in low amounts, the researchers said. Schindler said he was particularly concerned about mercury in the water, because levels of that metal already are elevated in the Athabasca watershed.

Officials with Alberta Environment, an arm of the provincial government, said they respected Schindler and would consider his data. But, they said, their current findings differ.

Preliminary data from a three-year government study set for release next year show that the majority of pollutants in the river are not a result of man-made activity but caused by "natural" forces such as the erosion of riverbank soil into the water, said Preston McEachern, head of science, research and innovation for Alberta Environment.

Industry maintains pollutants exist even without oil sands

The agency data show that the level of contaminants have not changed much since the 1970s. If oil sands production were causing the elevated levels, the numbers should have shot up since then, McEachern said.

The Regional Aquatic Monitoring Program, an industry-funded group sharing data with the Albertan government, also says its data show that the oil sands have not increased contaminants in the river.

Schindler's results of a "bull's-eye" effect are not surprising, considering that companies are building facilities where the river basin holds the most oil and naturally occurring chemicals to seep into waterways, said program spokesman Fred Kuzmic. In other words, the river would contain pollutants regardless of whether oil sands businesses were in the region, he said.

To that, Schindler responded, "Cannot these people read?" His research team specifically examined bitumen-rich areas that don't have accompanying industrial facilities, he said, and did not find the same level of water contamination as in bitumen-rich areas where humans have mined and processed oil.

The Canadian government's own data show that companies have increased the release of mercury, lead and zinc near the river, according to Schindler. There's something wrong with prior data if that isn't being detected in the environment, he said.

He called the Regional Aquatic Monitoring Program a failure and said it should be scrapped entirely. A 2004 review of the program by outside scientists found numerous problems in how the organization collects data, and there have been few changes since then, he said.

Kuzmic said it was "unfortunate" that Schindler was basing his criticism on old information from 2004. He said the program has changed since then, and another independent review will be forthcoming this year.

Stelmach calls for talks

Canadian government officials got caught in the crossfire last week.

At a press conference, Premier Stelmach called for government scientists to sit down with Schindler to investigate why government-backed reports seemingly are providing data that oppose the data in the new paper. Oil sands production is not going to stop because of its beneficial economic impact, he said, so it's important to make sure waterways are protected.

"Let's compare the data and see where the differences are, and then sit down and change whatever regulations are necessary to do that if that's the case," Stelmach said to reporters.