Although the earth is large, it is a closed system, and all kinds of substances on the earth have a complex cycle process - the same is true of pollutants. Scientists point out that anything released on the earth may remain somewhere on the earth and be released again. Now, for example, according to a new study, scientists point out that melting glaciers in the Himalayas are releasing pollutants accumulated year after year into downstream ecosystems.
As global warming progressed, glaciers accumulated in the Himalayas of the Qinghai-Tibet Plateau began to melt, a process that began in the 1940s and was thought to have an impact on water resources and climate, and scientists now point out. During this process, dangerous pollutants such as pesticides accumulated in glaciers and ice sheets will be released again. These pollutants released by glaciers may enter lakes in the Himalayan region, which will gradually accumulate in local aquatic organisms and fish, and eventually poison humans at the top of the food chain through food chain enrichment.
Researchers in the new study say that even the most remote parts of the planet, such as Himalayas, can be a reservoir of pollutants, as can the Arctic. Previous studies have shown that the Arctic contains a large amount of mercury, which could have a serious impact on the Earth's environment if released completely. Researchers from the Chinese Academy of Sciences point out that glaciers in the Himalayas contain higher levels of pollutants than glaciers in other parts of the world, because they are often close to the most polluted South Asian countries in the world.
The study also pointed out the way pollutants diffuse in the Earth's circulation - pollutants can be transported over long distances through dust particles and water molecules in the atmosphere. For example, in the Arctic and Antarctica, scientists have identified high levels of pollutants in the ice sheet, which have moved thousands of kilometers before falling into the ice and melting into the glacier. This highly polluting phenomenon away from pollution sources is known as the Arctic Paradox, and it also occurs in alpine glaciers such as the rarely traveled Himalayas.
Namco, for example, is located in the central part of the Qinghai-Tibet Plateau. It is also one of the important lakes affected by the melting of glaciers in the Himalayas. Researchers measured the concentration of a chemical called perfluoroalkyl acids (PFAAs) in the Namco Lake Basin. By testing water samples collected in the Namco Lake Basin, the researchers found that the glaciers in the area release about 1342 mg of PFAAs to Namco every day, and ultimately, scientists believe that the total amount of PFAAs in a year is about 1.81 kg per year.
The rapid influx of this chemical may have an impact on lakes and aquatic life downstream. Kimberley Miner, a geochemist and climate scientist at the University of Maine at Orono, said that PFAAs are known to have a very long life span and are less biodegradable, so they can easily pass through biological and ecological systems. And various biogeochemical processes continue to concentrate. Therefore, people who eat fish in Namco for a long time or live near Namco may face serious health risks.
At the same time, scientists also pointed out that Namco's water also directly enters India's water resources network, which means that India, which releases pollution, also has to bear its own fruit.