[ad_1]
The fallout from humanity's nuclear heritage is locked in glaciers around the world. Scientists are now worried about the possibility that it is infiltrating into the environment, as climate change is causing the melting of Arctic ice.
This apocalyptic scenario was studied by an international team of scientists who examined the spread of radioactive contaminants in Arctic glaciers across Sweden, Iceland, Greenland, the Norwegian Svalbard Archipelago, the European Alps, the Caucasus, British Columbia and Antarctica. The researchers shared their findings at the 2019 General Assembly of the European Geoscience Union (EGU) in Vienna last week.
Fallout radionuclides (FRN) were detected at 17 sites at these sites. Radioactive material has been found embedded in ice surface sediments known as "cryoconite" and at concentrations ten times higher than those of the environment. "These are extremely high concentrations in the environment outside of nuclear exclusion zones," said Caroline Clason, speaker. in physical geography at the University of Plymouth, who led the research project, told AFP on Wednesday.
Scientists have attributed to the bulk of debris the advent of nuclear weapons tests in the 1950s and 1960s. The Chernobyl disaster in 1986 and the Fukushima crisis in 2011 were also at the beginning. Origin of certain consequences.
"If we take a core of sediment, you can see a clear tip where Chernobyl was, but you can also see a fairly definite peak around 1963, when there was a period of heavy weapons tests "said Clason.
Weapon tests can throw radioactive detritus up to 50 miles in the air. According to the Environmental Protection Agency, smaller, lighter materials will travel in the upper atmosphere and may "circulate the world for years, even decades, until they settle." or are brought to the surface by precipitation.
The fallout is composed of radionuclides such as americium 241, cesium 137, iodine 131 and strontium 90. Depending on the half-life of a material, it may remain in the environment for a few minutes to a few years. before breaking down. Their radiation levels also vary.
Particles can return to the immediate vicinity in the form of acid rain that is absorbed by plants and the soil, which damages ecosystems, human health and communities. But radionuclides that travel long distances can settle at levels concentrated on snow and ice: large amounts of radioactive material from Fukushima were discovered in 2011 on four glaciers on the Tibetan plateau, for example.
The americium, which Clason described as "particularly dangerous" for its greater solubility in the environment and its more powerful radiation emitter, is produced by the decay of plutonium and cesium, which were discovered on some glaciers. The Swiss glacier Morteratsch, containing the highest cesium level, according to ScienceAlert.
The team is hopeful that future research will examine how spillovers could be dispersed into the food chain from glaciers, calling it a "secondary source of environmental contamination many years after the nuclear event of their origin."
A study published this week in Nature studied 19,000 glaciers on Earth and found that their total melt was equivalent to a loss of 335 billion tonnes of ice per year, which is higher than previous studies.
"These materials are a product of what we put in the atmosphere," said Classon. "It just shows that our nuclear heritage has not disappeared yet, it's still here."
[ad_2]
Source link