Yukon River Gets Mercury Boost from Permafrost

Investigators at the United States Geological Survey (USGS) have recently completed a new study on the origins of elevated mercury concentrations in the Yukon River, one of the longest free-flowing rivers in the world. The team discovered that thawing permafrost was the primary contributor.

Naturally-occurring mercury has been discovered in most of the world's rivers, but the Yukon releases between 3 and 32 times more of the chemical into the environment than any of 8 other major rivers in the Northern Hemisphere.

Throughout the Yukon watershed, about 5 tons of mercury are circulated every year. This also includes methylated mercury, the variety that is very toxic to humans. Fortunately, concentrations of this version of the element are reduced.

“It is important to measure the amount of mercury from river watersheds so that a baseline is established to compare against future conditions,” USGS lead study researcher Paul Schuster explains.