Within the human-generated category, Asia contributes nearly 50 percent of mercury emissions, with North America at 7 percent and Europe and North Africa at 12 percent combined, according to Jerry Lin, a professor of environmental engineering at Lamar University in Texas. In addition to coal-fired power plants, a major source of mercury emissions is small-scale gold mining. Miners working on their own often use mercury to help extract gold and then boil it off, leaving behind dangerous contamination.
The effects of mercury contamination are not limited to the local environment. Mercury finds its way into the sea, affecting fish like bluefin tuna, and airborne emissions can travel between continents.
“The mercury today will continue to circulate in the system for a long time,” Dr. Selin said. “We’re talking decades to centuries.” Methyl mercury, the toxic form, even poses a substantial problem for the Arctic, she said, because it can accumulate in polar bears and seals.
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