A new study from scientists at the University of Waterloo and Wilfred Laurier University has concluded that oilsands mining is not emptying metal concentrations into the Athabasca Delta, located 200 km away from the oilsands.
Funded by Suncor and published in Environmental Research Letters, the study found that the area doesn’t have higher concentrations of metals than what would be there naturally.
The researchers used lake sediment samples from a pre-industrial period to generate a baseline for metal concentrations in the Athabasca River that could be compared to present-day samples.
First Nations in the Athabasca region have expressed concern that oilsands development is polluting their food sources.
“We didn’t find evidence of metal concentrations being elevated above the natural baseline,” said study co-author Roland Hall, a biologist at the University of Waterloo.
“We can’t say the oilsands are not adding contaminants to the system; we can say that whatever it is adding is not causing the concentration in river sediment to go up at the Athabasca Delta.”
Hall notes that metal concentrations in river sediment can vary and change, suggesting even higher concentrations of metals may be found in lakes .
The researchers’ approach is novel given its use of lake data to gauge river sediments. The method has been suggested by researchers in the past, but never tested.
“People have floated the idea that we could use sediment records that we get out of lakes to assess pollution. It really hasn’t been done,” said Hall.
“Because we worked in flood plains where our lakes are strongly influenced by rivers, we thought about this and realized our lake science coring tools could give some answers about rivers.”
The most important part of the study is that the measurement technique could be used by regulators or scientists looking to evaluate metal concentrations or other pollutants in rivers in Canada and around the world.
“We have found a useful method that can be used widely around the world,” said Hall.
“This can work for any river where there are flood plain lakes that store sediments that the river carried back before human activity began. Most of our industrial centres lie on low rivers and the sediments can provide that information.”
He said nobody has previously collected this data.
“Up until this study I think it is fair to say that no one had any idea of the natural level of contaminants carried by the Athabasca River before oilsands activity or even before a lot of other human activities along the river,” he said.
“All that we think we have known to this point is based on measurements without that context.”
Next, the research team plans to use the same method to study the Athabasca River sediment further upstream where oilsands mining and processing activities occur.
Kaven Baker-Voakes is a freelance reporter based in Ottawa.