Mercury pollution resulting from early coal burning and gold mining continues to affect Arctic wildlife over a century later. New research published in Natural Communication reveals these enduring effects.
Despite worldwide efforts to limit emissions, mercury levels in apex predators like Arctic and toothed whales remain alarmingly high. Researchers attribute this persistence to legacy contamination that travels through ocean currents to the Arctic region.
A research team has analyzed more than 700 samples collected across Greenland over the last 40 years, ranging from animal tissues to ground peat. By evaluating the chemical “fingerprints” of mercury isotopes, they discovered that mercury concentrations have not declined and, in some cases, remain elevated in Arctic ecosystems.
“This provides insight into why we haven’t seen a decrease in Arctic mercury levels,” stated Professor Runeatz, a co-author of the study. “Mercury transport from significant sources like China to Greenland can take up to 150 years.”
Mercury released into the atmosphere through human activities can circulate the globe for approximately a year before settling. However, once it enters the ocean, it may persist for centuries, gradually moving northward through deep, cold currents.
For instance, Central West Greenland is influenced by Atlantic influx via the North Atlantic Arminger current, while other areas receive mercury-laden water from the Arctic current.
Currently, mercury concentrations in polar bears and toothed whales are 20-30 times higher than pre-industrial levels.
“We don’t have evidence of actual killings of top predators,” Dietz commented. According to an email from BBC Science Focus, “However, the loads in toothed whales and polar bears, along with Inuit populations in highly exposed areas, are significant enough to indicate neurological effects.”
As a potent neurotoxin, mercury can harm immune and reproductive health. Naturally occurring elements are extremely dangerous, as noted by the World Health Organization, which lists it as “one of the top 10 chemicals of major public health concern.”
The findings carry significant implications for the United Nations Mamata Treaty, a global initiative aimed at decreasing mercury pollution. While reduction of emissions is crucial, the study implies that the Arctic may require generations to see recovery.
The research team will continue to explore mercury’s impact on vulnerable Arctic ecosystems. Dietz emphasizes that modeling how long mercury takes to travel from major emitters like China to various Arctic regions could be essential for understanding long-term threats.
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About our experts
Rune Deets is a professor at the Faculty of Ecoscience at Aarhus University. His research has been published in peer-reviewed journals including Environmental Research, Molecular Ecology, and Ecology and Evolution.
Source: www.sciencefocus.com
