Chemical & Engineering News: Trove Of Toxic Mercury Lurks In Arctic Sea Ice
Chemical & Engineering News reports on the research of UM grad student Sarah Beattie from the Centre for Earth Observation Science (CEOS) in the Clayton H. Riddell Faculty of Environment, Earth, and Resources.
As the article opens:
People and animals living in the Arctic tend to have high amounts of mercury in their tissues, and now researchers have uncovered a growing source of the most toxic variety of the metal. The team reports that Arctic sea ice holds large amounts of methylmercury that may enter marine ecosystems at increasing rates as the ice melts due to climate change (Environ. Sci. Technol. 2014, DOI:10.1021/es5008033).
The study is the first to measure methylmercury in so-called multiyear Arctic sea ice, a long-lasting form of the ice that sits atop the open ocean waters. Lars-Eric Heimbürger, a chemical oceanographer at the University of Bremen, in Germany, who was not involved in the study, says the work is important because it suggests that as more of this ice melts due to rising temperatures, more methylmercury will enter Arctic food webs.
The ice cores had mercury concentrations ranging from 0.65 to 60.8 pM. Concentrations of the methylated form peaked at 2.64 pM. Those values may seem small, Beattie explains, but methylmercury is highly potent, and its concentrations can increase by a factor of a million or more as it travels up the food chain. Based on these findings, Beattie’s team estimated that, at the current rate of ice melt, 42 kg of methylmercury enters the Arctic ecosystem each year.
To better understand how climate change will affect this source of methylmercury, Beattie and Bremen’s Heimbürger say researchers should collect ice at non-Canadian Arctic sites. That data would help determine mercury distribution across the Arctic.