International Joint Commission Calls for Improved Great Lakes Atmospheric Mercury Monitoring


The International Joint Commission (IJC), concerned by the lack of sustained funding for the number of monitoring sites, is recommending in a report released today that the Canadian and U.S. governments provide stable long-term funding to monitor atmospheric deposition of mercury in the Great Lakes region.  The Commission is concerned that mercury concentrations in some Great Lakes fish in some locations are increasing or may increase in some fish species in the future due to significant increases in coal burning in Asia.

"If we want to assure that fish from the Great Lakes are a source of healthy food, that does not diminish the ability of our children to fully use their brains, we need a better handle on mercury deposition," said Lana Pollack, U.S. Co-Chair of IJC. "Meeting the Great Lakes Water Quality Agreement objective on fish consumption unrestricted by contaminant concerns, will require greater investments in monitoring."

"The Commission is urging continued vigilance to better understand the extent of mercury deposition in light of the possibility of increased long-range deposition in the Great Lakes," said Benoit Bouchard, Canadian Commissioner of IJC.  "This means sustained and adequate funding for monitoring."

A toxic metal, mercury occurs naturally in coal.  Like many other contaminants, it can be transported vast distances – across oceans and continents -- from its emission source and pollute distant ecosystems.  After deposition in these ecosystems, mercury can be converted to methylmercury, a form that poses human health risks. Impacts on cognitive functions including memory, attention, language, and fine motor and visual spatial skills have been seen in children who were exposed to methylmercury in the womb.         

Canadian mercury emissions decreased 85% between 1990 and 2010.  U.S. mercury emissions decreased approximately 60% between 1990 and 2005.   While these improvements are laudable, a U.S. National Oceanic and Atmospheric Administration 2011 report estimated that China (14%) was second to the U.S. (32%) in contributing mercury to the Great Lakes basin – and that the contribution from overseas is increasing.  To address the ever-changing global context of mercury emissions, funding for modeling to assist with analysis of the geographic sources of mercury deposition in the Great Lakes is also important, the Commission said.

Approximately 50 mercury wet-deposition monitoring sites from four networks operated in the Great Lakes states and Ontario from 1996 to 2010.  By 2013, 20 of those sites were no longer in operation. Although state members of the Lake Michigan Air Directors Consortium (LADCO) are temporarily channeling funds to support a U.S. Great Lakes atmospheric mercury monitoring network, a long-term federal commitment to fund monitoring on both sides of the border is advisable, the Commission says in a report released today.  The Commission estimates an annual cost of approximately $250,000 to operate an adequate monitoring network, with additional funding for Ontario monitoring sites.

The Commission also commends the U.S. and Canadian governments for signing in 2013 a treaty called the global Minamata Convention, which commits parties to mercury emissions control and reductions when it comes into force, with ratification by 50 nations.  The Convention is named after Minamata, Japan, where exposure to industrial mercury in the 1950s led to birth defects and other impairments in children.

The Commission encouraged the two federal governments to pursue global actions to reduce other contaminants reaching the Great Lakes from distant sources, including some chemicals banned in the U.S. and Canada but still in use elsewhere.


The International Joint Commission was established under the Boundary Waters Treaty of 1909 to help the United States and Canada prevent and resolve disputes over the use of the waters the two countries share.  Its responsibilities include reporting on progress made under the Great Lakes Water Quality Agreement between the nations toward restoring and maintaining the chemical, physical and biological integrity of the Great Lakes and connecting waters. 

For more information on atmospheric deposition of mercury in the Great Lakes, see the full report here.

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Nick Heisler



Frank Bevacqua