Dec. 13 () –
Unprecedented anomalies in the accumulation of plutonium isotopes in glaciers in the southern hemisphere, specifically in Patagonia of Chile, may be related to accidents such as the fall of the Russian space probe Mars-96.
It is the result of an analysis of samples of cryoconite, a sediment that accumulates in glaciers, by scientists from the Institute of Nuclear Physics of the Polish Academy of Sciences.
Glaciers play a vital role in providing fresh water. Its melting, caused by global warming, can have serious consequences: from rising sea levels to reducing water resources, which are of key importance for energy production in hydroelectric plants. Additionally, radionuclides and other contaminants released from ice They can migrate to nearby ecosystems, where they can accumulate and affect the food chain.
Radioactive elements are present in the environment as a result of natural processes and human activity. Man-made radionuclides, such as plutonium, are released into the environment primarily through nuclear tests, reactor accidents or failures of satellites and space probes containing radioactive energy sources.
These substances, transported mainly through the atmosphere, accumulate in different ecosystems, including glaciers, in the form of dark sediments called cryoconite. A typical cryoconite hole is no more than a few tens of centimeters in diameter and depth. At its bottom, there is a dark sediment called cryoconite. Contains organic material and contaminants, that is, radionuclides, heavy metals, pesticides, microplastics or antibiotics. This sediment can pose a potential threat to local ecosystems.
The latest research carried out at the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) with the use of new mass spectrometry methods allowed researchers to create a database of plutonium isotopes (238,239,240Pu) in glaciers of the northern and southern hemispheres. The cryoconite samples analyzed came from 49 glaciers in nine regions of the world, including the Arctic, the Alps, the Himalayas and Antarctica. The material was collected by an international team of researchers during the years 2000-2020.
“These are the first analyzes of plutonium concentration in cryoconite samples carried out on such a large scale,” he says. in a statement Dr. Edyta Lokas (IFJ PAN), initiator and first author of the article published in Science of the Total Environment.
The results of the study have provided unique information on the accumulation, distribution and sources of plutonium isotopes in glaciers. The activity concentration of 239+240Pu was found to be much higher in the northern hemisphere than in the southern hemisphere, reflecting uneven deposition of Pu from nuclear weapons testing between the hemispheres.
As for the northern hemisphere, the highest concentrations are observed in Scandinavia and the Alps. No relevant differences have been observed between the hemispheres in the case of 238Pu. Southern hemisphere cryoconite is characterized by high heterogeneity both in terms of Pu activity and mass ratio.
SOVIET SPACE PROBE SUNK OFF THE COAST OF CHILE IN 1996
The isotopic ratios of 238Pu/239+240Pu, hitherto unprecedented in literature, have been observed for the first time in cryoconite of the Exploradores glacier in Chilean Patagonia. The researchers hypothesize that excess 238Pu It may be related to the fall of the Soviet space probe MARS-96, which sank into the ocean off the coast of Chile in 1996.
The space probe contained a generator with 238Puwhich may explain the higher concentrations of this isotope in the nearby glacier. The study results are the first observations of their kind showing anomalies in plutonium isotope ratios in the Southern Hemisphere.
Furthermore, cryoconite samples from South American glaciers showed 240Pu/239Pu mass ratios significantly different from those found in the literature, which may suggest that the dominant source of Pu is related to low-altitude nuclear testing conducted in the area of French Polynesia.
“The concentrations of plutonium activity in cryoconite that we have observed are, especially in the northern hemisphere, orders of magnitude higher than those of other environmental matrices used to monitor the environment, such as lichens, mosses, soils and sediments. At the same time , our discoveries emphasize the importance of cryoconite in accumulation of radioactive contaminants that may pose a potential threat to surrounding fauna and flora and, at the same time, they can help us track the spread of these contaminants,” says Dr. Lokas.
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