Concerns over oilsands river contamination overstated, scientist says

Shotyk found little difference between lead and arsenic levels in either direction from the mines. Levels of lead dissolved in the water were vanishingly small — comparable to those found in Arctic ice that is thousands of years old.

He did find downstream increases in heavy metals associated with bitumen, such as vanadium, nickel, molybdenum and rhenium. But those levels are still tiny.

As well, Shotyk said previous research has focused on total concentrations, instead of just what is dissolved in the water column. Unless a metal is in solution, he said, organisms simply don’t absorb it.

The same holds true for arsenic concentrations in the river, says one of the papers. A third comes to a similar conclusion for snowmelt — that any heavy metals entering the Athabasca do so as particles, often bonded to clay minerals.

“Somehow, metals and minerals have been confused,” Shotyk said.

That’s why, he said, previous research has reported concentrations of some heavy metals in the Athabasca are already at levels considered hazardous to fish. Shotyk said Canadian water quality standards that stipulate total concentration and not just dissolved content are out of date.

“I think the folks that are working on these guidelines have to move ahead analytically and have a look at the dissolved fraction.”

Previous research by ecologist David Schindler and aquatic biologist Jules Blais are both referenced in Shotyk’s papers. Both criticize the work of their colleague.

Schindler said he deliberately sampled the river during the summer peak flow, when runoff would be highest. Shotyk’s samples were taken in autumn.

“That is almost certainly why we were able to detect higher arsenic near and downstream of the oilsands and they were not,” he wrote in an email.

Blais questioned Shotyk’s assertion that contaminants have to be dissolved before plants or animals can absorb them.

His lab has exposed aquatic animals to sediments containing oilsands materials. Preliminary results suggest the contaminants are being passed on, said Blais.

“The ones that have contact (with the sediments) have higher metal accumulations than those that are screened away from the sediments. We know that the sediments are a source of exposure.”

Schindler pointed out his work has never claimed contaminant levels exceed quality guidelines.

“There are few exceedances even there, when one considers a metal at a time, which is how the guidelines are based. But there really are no guidelines for drinking a devil’s brew of several metals and organic compounds that are detectable, but below guidelines.”

Shotyk’s research was funded by the Alberta government and an industry group focused on environmental research.

“Our work has not been affected by the source of funds,” he said.

“The folks funding our work simply want the facts. They want to see quality science and that’s our goal too.”

— Follow Bob Weber on Twitter at @row1960

Bob Weber, The Canadian Press

by Canadian Press

Concerns over oilsands river contamination overstated, scientist says

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