TRAVERSE CITY, Mich. The U.S. and Canada should more closely monitor atmospheric pollution from as far away as Asia that may be causing mercury levels to rise in some Great Lakes fish, an advisory agency said Thursday.
Many of the stations that once monitored the mercury content of rain and snow in the region are no longer operating, according to a report by the International Joint Commission, which recommends policies to both nations’ governments on their shared waterways.
It calls for the U.S. to spend $250,000 a year on a network of 21 stations across the eight states that border the Great Lakes. It says Canada also should contribute funding for stations in the province of Ontario, but it doesn’t recommend specific numbers.
“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, the commission’s U.S. co-chairwoman.
Mercury is a toxic metal that exists naturally in coal. When spewed into the atmosphere from power plants and other sources, it can travel across oceans and continents before falling back to earth.
When deposited in waterways, it can be converted to a more toxic form called methylmercury and build up in fish, posing risk to humans. Mercury can damage immune and nervous systems, particularly in children.
States throughout the region post advisories about fish consumption, partly because of mercury pollution.
Although mercury emissions in Canada and the U.S. have fallen significantly, they have jumped in China. The National Oceanic and Atmospheric Administration said in 2011 that China ranked second to the U.S. as a mercury source in the Great Lakes watershed and that contamination from overseas was on the rise.
Determining where mercury is coming from will enable the U.S. and Canada to “devise appropriate, cost-effective control strategies,” the International Joint Commission report says. “It will also underscore the importance of controlling emissions globally and support international co-operation to attain that objective.”