Water released by permafrost contains uranium, arsenic in levels unsafe for drinking
As the climate warms and arctic permafrost thaws, some of the toxic elements locked away in it are starting to emerge and could contaminate the water supplies that many northern communities rely on.
Elliott Skierszkan, a geologist at Carleton University, and his colleagues recently measured the concentrations of naturally occurring uranium and arsenic in water released from permafrost samples collected in the Yukon.Video: Protecting northern water supplies from toxic metals in thawing permafrost
“Our samples had levels of uranium and arsenic in the water beyond what would be considered safe,” he says. The work was published in two papers, in Environmental Science and Technology, and ACS Earth and Space Chemistry.
Using the Canadian Light Source at the University of Saskatchewan, Skierszkan also probed the chemical composition of the elements in the solid portion of the permafrost. They found that uranium was largely associated with organic carbon in the soil, while arsenic was associated with iron oxides. “The synchrotron was essential to understanding the chemistry of these elements and their potential to be mobilized,” says Skierszkan.
The results showed that the fate of both elements was linked to organic carbon. As the permafrost thaws, the organic matter it contains breaks down, which can release associated uranium. This decaying organic matter can also cause the iron oxides and the arsenic associated with them to dissolve into the water.
Read more on the CLS website
Image: Protecting northern water supplies from toxic metals in thawing permafrost
Credit: Canadian Light Source