In the blue

After spending decades controlling atmospheric emission of mercury, the world wakes up to the possibility that rivers are a major source of the toxic metal in the oceans

- KIRAN PANDEY

WHILE THE world has always known about the presence of toxic mercury in the oceans, it believed the atmosphere was the primary source of the heavy metal that poisons fish and other marine life. Now, researchers at Yale School of the Environment, US, claim rivers are the real culprit, and that they flush more than 1 million kg of hazardous mercury into oceans each year.

“The findings of the study kind of rewires the global mercury cycle,” says Peter A Raymond, lead author of the study published in Nature Geoscience on July 22. “Our estimate is threefold of that suggested by the United Nations Environment Programme (UNEP) Global Mercury Assessment, 2018, which highlights that rivers are an important but overlooked source of the global mercury cycle,” he adds.