An estimated 15 million gallons (56.8 million litres) of mercury stored in frozen Arctic permafrost will be the next climate-related health risk to worry about as the region thaws, according to a new study this week in the journal Geophysical Research Letters.
Mercury is a powerful neurotoxin for humans and wildlife, and the Arctic holds nearly twice as much of it as all other soils, the oceans, and the atmosphere combined, InsideClimate News reports.
“It really blew us away,” said lead author Paul Schuster, a Boulder, Colorado-based hydrologist with the U.S. Geological Survey.
“The mercury that ends up being released as a result of the thaw will make its way up into the atmosphere or through the fluvial systems via rivers and streams and wetlands and lakes and even groundwater,” he explained. “Sooner or later, all the water on land ends up in the ocean.”
While the concentration of mercury in Arctic permafrost is the first half of the story, Schuster said the next question is how it will move through global food webs.
“Mercury is a bioaccumulator, meaning that, up the food chain, species absorb higher and higher concentrations. That could be particularly dangerous for Native people in the Arctic who hunt and fish for their food,” InsideClimate News notes. “Exposure to even small amounts of mercury can cause serious health effects and poses particular risks to human development.”
Grist adds to the explanation: “Mercury is a toxin that can cause birth defects and neurological damage in animals, including humans. And mercury levels accumulate as you go up the food chain, which is why king-of-the-jungle species like tuna and whale can be unsafe to eat in large quantities.”
And once the mercury reaches the ocean, it won’t be restricted to the Arctic, Schuster noted. “It’s possible that fisheries around the world could eventually see spikes in mercury content,” ICN states.
The severe, permanent effects of environmental mercury poisoning were identified decades ago in Minimata, Japan, and mercury poisoning at the Asubpeeschoseewagong/ Grassy Narrows and former Whitedog First Nations in Ontario is an urgent and unsolved public health issue to this day.
“Food sources are important to the spiritual and cultural health of the Natives, so this study has major health and economic implications for this region of the world,” Edda Mutter, science director for the Yukon River Inter-Tribal Watershed Council, told InsideClimate.