Scientists measured ground mercury levels following the opening of a lead, or tract of exposed seawater formed by the cracking of Arctic ice, off the coast of Barrow, Alaska.
The process is also referred to as “pumping,” and so happens because the exposed water is far warmer than the air above it. As a result, the air above the lead moves rapidly, much like water boiling in a pot.
“The mixing is so strong, it actually pulls down mercury from a higher layer of the atmosphere to near the surface,” said Chris Moore, of the Desert Research Institute and lead author of the study.
The mixing quickly forms dense clouds that form about 400 metres into the sky, where the “pumping” process may happen.
More troubling is the report that leads are becoming more and more common.
“Over the past decade, we’ve been seeing more new sea ice rather than perennial ice that has survived for several years,” said Son Nghiem, a co-author of the study and scientist at NASA’s Jet Propulsion Laboratory. “New ice is thinner and saltier and cracks more easily. More new ice means more leads as well.”
Alexandra Steffen, a mercury specialist with Environment Canada, told the Vancouver Sun that the ever-changing sea-ice situation is altering and increasing the amount of mercury entering the Arctic. “It’s all of a sudden a much more dynamic environment,” she said.
Mercury pollution in the atmosphere apparently originates almost entirely in the far south, as a result of wildfires, coal burning, gold mining and more, as UPI mentions. This report comes at an opportune time, Nghiem pointed out.
In October of last year, countries began to sign the Minamata Convention, a global treaty meant to curb mercury pollution. So far 94 countries have signed, and Nghiem believes the study will be useful in determining the Convention’s effectiveness.
