Fellows in the News

Melting Himalayan glaciers are releasing decades of accumulated pollutants into downstream ecosystems, according to a new study.

The new research in AGU’s Journal of Geophysical Research: Atmospheres finds chemicals used in pesticides that have been accumulating in glaciers and ice sheets around the world since the 1940s are being released as Himalayan glaciers melt as a result of climate change.

These pollutants are winding up in Himalayan lakes, potentially impacting aquatic life and bioaccumulating in fish at levels that may be toxic for human consumption.

The new study shows that even the most remote areas of the planet can be repositories for pollutants and sheds light on how pollutants travel around the globe, according to the study’s authors.

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That kind of influx of PFAAs can have an impact on aquatic life in the lake and downstream, said Kimberley Miner, a geochemist and climate scientist at the University of Maine in Orono who was not involved in the new study.
 
PFAAs are known for having a very long lifespan. The chemicals don’t regularly biodegrade and are readily passed through organisms and ecosystems, while being continually concentrated through various biogeochemical processes, Miner said. The new study did not include a toxicity risk assessment of these levels on aquatic life, but previous studies suggest that eating fish caught in the lake could be detrimental to human health, she says.

“The bioaccumulation potential for these chemicals is extraordinary,” Miner said.

First, microorganisms and insects take up molecules into their tissues, then fish and other predators eat them, passing the contaminants up the food web in higher and higher concentrations.

“This [Nam Co Basin] water also feeds directly into the water resources in India,” she added.

The study adds important data to the bigger picture of how pollutants cycle around the globe, Miner said. Similar studies have been conducted at the poles and in Europe, but not as much is known about pollutants in the Himalaya. Each mountain range has its own characteristics that influence how chemicals move through the environment, she added.

“The Earth is a closed system. Everything released on the Earth, stays somewhere on the Earth,” Miner said.

 

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