A five-year sampling shows the basin, which is roughly twice the size of California, has mercury levels 32 times that of some other rivers included in the study, published this week in the journal Environmental Science and Technology.
One USGS researcher, however, said the high levels, pose little threat to humans or to wildlife.
"We have several hypotheses about (the cause) and one of them is the thawing permafrost . . . which is in direct response to a warming climate," said Paul Schuster, a hydrologist with the USGS national research program.
"Our data sets don't tie (mercury and climate change) together, but they do suggest it."
The researchers took samples from the region between 2000 and 2005, and measured total mercury, which includes dissolved mercury and particulate mercury as well as the element's other forms, such as the more harmful methylmercury, which can get into tissue. Read the full report here.
Source: by Bradley Bouzane, Postmedia News, The Vancouver Sun.
