High levels of toxic pollutants in Alberta's Athabasca River system are linked to oilsands mining, researchers have found.

The findings counter the reports by a joint industry-government panel that the pollutant levels are due to natural sources rather than human development.

Mercury, thallium and other pollutants accumulated in higher concentrations in snowpacks and waterways near and downstream from oilsands development than in more remote areas, said a study to be published Monday afternoon in the Proceedings of the National Academy of Sciences.

Upstream and undeveloped sites exposed directly to the McMurray Geologic Formation, the natural source of the oilsands, did not show high levels of pollutants.

The study led by Erin Kelly and David Schindler of the University of Alberta also found that levels of the pollutants cadmium, copper, lead, mercury, nickel, silver and zinc exceeded federal and provincial guidelines for the protection of aquatic life in melted snow or water collected near or downstream from oilsands mining.

"They're all elements that are known to be very toxic at low concentrations," Schindler said. He added that natural levels of some elements are already high in waters in that area.

"Adding more is certainly not going to do the ecosystem any good."

Researchers at Queen's University in Kingston, Ont., and Juneau, Alaska-based Oceana, a non-profit group focused on water quality issues, also contributed to the report. The study was funded by the Tides Foundation and the Walter and Duncan Gordon Foundation, two non-profit groups with an interest in environmental projects.

Residents downstream from the oilsands have expressed concerns that pollution in the river may be causing increased cancer rates.

However, the Regional Aquatic Monitoring Program, or RAMP, a joint industry-government environmental body that monitors water in the Athabasca River and its tributaries, said in its 2009 report that generally, "water quality was similar between [test] stations located within and outside oil sands development and when compared to conditions prior to development."

The program has reported the pollutant levels occur naturally because of erosion of the natural geologic formation that contains the oilsands and are not caused by human activity.

Goal to test claims of monitoring program

The authors of Monday's study said they wanted to test those claims.

As of 12:30 p.m. ET, RAMP had not responded to requests for comment from CBC News.

RAMP's findings have been questioned in the past, but critics did not have any data from independent studies to compare to the program's data, the paper said.

The new findings confirm "the serious defects" of the monitoring program, the study concluded. It added that detailed monitoring, including the ability to distinguish the sources of the contaminants, is "essential" to control the potential impact of pollutants on human health.

Schindler said the levels of pollutants found by his study were easily measurable and "any program that cannot detect these levels has to be considered incompetent."

He called for Environment Canada to take over monitoring.

The researchers collected water from more than 35 sites in February and June 2008 along the Athabasca River, its tributaries, the Athabasca Delta and Lake Athabasca. They accumulated winter snowpack from 31 other sites in the region in March 2008.

The researchers chose sampling sites upstream and downstream from oilsands mining, with both within 50 kilometres of oilsands developments and near undeveloped oilsands sites.

They then tested the samples for levels of 13 elements listed as priority pollutants under the U.S. Environmental Protection Agency's Clean Water Act.