Gaby
A study from Aarhus University in Denmark has revealed that mercury pollution from a century ago, from coal burning and gold mining, continues to poison the Arctic environment. Despite global efforts to curb harmful emissions, mercury levels in the bodies of large predators like polar bears and sperm whales remain alarmingly high. Researchers attribute this to legacy pollution carried to the Arctic by ocean currents.
What did the scientists discover? A team led by Professor Rune Dietz analyzed over 700 samples collected across Greenland over the past 40 years, ranging from animal tissues to peat soil. By studying the chemical signatures of mercury isotopes, the researchers found that its concentration in Arctic ecosystems has not decreased over time. In fact, in some cases, it continues to rise.
According to Professor Dietz, “The transport of mercury by ocean currents from major sources, such as China, to Greenland can take up to 150 years.” Mercury released into the atmosphere from human activities can circulate around the globe for about a year before settling back to Earth. However, once it enters the ocean, it can remain there for centuries, slowly moving northward through deep, cold currents. For instance, central West Greenland is influenced by the Irminger Current in the North Atlantic, while other regions receive mercury-laden water from currents in the Arctic Ocean.
Currently, the concentration of mercury in polar bears and sperm whales is 20 to 30 times higher than pre-industrial levels, as reported by BBC Science Focus. Mercury is a potent neurotoxin that damages the immune system and reproductive health. Mercury is so dangerous that the World Health Organization lists it among the ten chemicals of major health concern.
Researchers predict that restoring the Arctic will require the efforts of many generations. The team plans to continue studying the impact of mercury on the fragile Arctic ecosystem. According to Professor Dietz, modeling the time needed for mercury to travel from major emission sources to different regions of the Arctic could be key to addressing this long-term threat. The findings of the study were published in the journal Nature Communications.
