Far from industrialized, pollution-producing cities and in the pristine environment of Glacier Bay, mercury has more than doubled during the past 15 years, researchers say.
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"There always was natural mercury, but we have increased that amount tremendously," said Dan Engstrom, the director of Minnesota's St. Croix Watershed Research Station during a recent telephone interview from Bartlett Cove. He and other scientists spent the past week doing the latest field tests for mercury in the national park.
Calling it a "global pollutant that knows no national boundaries," Engstrom compared mercury's trend to rising carbon dioxide levels, which also have increased sharply since the mid-19th century.
"On a global basis on average, we believe that humans have increased the levels about three times (since the industrial era)," he said.
Mercury largely has been used in manufacturing industrial chemicals and electronics and is emitted into the atmosphere when coal is burned - a common energy source in the rapidly growing nation of China.
East Asia is the likely origin for mercury that finds its way to Alaska, said Sonia Nagorski, a professor of geochemistry at the University of Alaska Southeast.
"We are downwind of the predominant air currents (from China), based on atmospheric models," she said.
Engstrom and Nagorski have spearheaded the work in Glacier Bay as part of an effort to determine the impacts of global industrialization on rural places and to help agencies such as the National Park Service in making land management decisions. They also want to bring awareness to the importance of controls on mercury emissions.
"In the U.S. there have been various proposals to limit mercury. Some of us don't believe that they don't do enough to limit mercury emissions here at home," Engstrom said.
While it will be several months before the results of the most recent tests are known, the scientists anticipate they will enable them to better understand what kind of natural environment most efficiently alters "elemental" mercury into methylmercury, which Nagorski said is about 100 times more toxic to humans.
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Past research has indicated that the waterlogged, bacteria-rich wetlands common in Southeast could cause the chemical change to occur more rapidly, Nagorski said. The scientists are therefore taking samples from more than a dozen streams - testing sediment, water, fish and insects to try and pinpoint in which landscapes the mercury accumulates best - and at what rate.
That rate appears to be increasing in Southeast Alaska more so than other rural areas where Engstrom has done research, including the Canadian Arctic, New Zealand and Uganda. Previous research indicated that this region was on the low end of mercury levels compared to the other areas. Now, Southeast is on par, Engstrom said.
Humans today are exposed to mercury primarily through the food they eat - and through the consumption of fish. Some fish-eating wildlife are believed to have been affected by the increase in mercury.
"We know for instance in other parts of North America, (mercury has likely caused) reproductive problems in loons," Engstrom said.
Engstrom said the research is not being done to create fear.
"We don't want people to be alarmed, we want them to be aware," he said.
Nagorski anticipates that only trace amounts of mercury will be found in water.
"I don't expect to see any mercury in the water that would be dangerous for consumption," she said.
Other members of the scientific team include John Hudson, a Juneau-based aquatic biologist, John DeWild and David Krabbenhot of the U.S. Geological Survey's Wisconsin District mercury lab, Eran Hood, a UAS assistant professor of hydrology and Nick Schlosstein, a UAS environmental science student.
The research is being funded by the National Park Service and is part of the university's contribution to the International Polar Year effort to better understand the Earth's polar regions.
Brittany Retherford can be reached at firstname.lastname@example.org or 523-2276. Read her blog, the Muskegger, at www.juneaublogger.com/naturalresources.