This haze of the Sahara it makes headlines every year for painting the sky in picturesque shades of orange. dust blown by the wind south. This has implications for infrastructure (eg reducing solar power generation) and human health (causing respiratory problems). But this dust carries with it Radioactive elements accumulating on the territory of Spain and other European countries, according to a newly published study by a group of scientists.
Europe experienced an extreme dust accumulation event in February 2021. It was on this occasion that scientists launched a civic science campaign of people living in certain snow-capped mountain ranges (including the Pyrenees). take snow samples which are then analyzed for dust. The initiative was led by Marie Dumont of the National Meteorological Research Center in France.
Volunteers and scientists collected 10 x 10 cm2 snow samples across the entire dust layer in the European Pyrenees and Alps (especially those stretching along France and Switzerland) from sea level to 2,500 m altitude. They then sent the melted ingredients to laboratories in Toulouse and Grenoble, France. samples were filtered and dried to analyze powder particles.
results, published Earth System Science Datareveals that 152 snow samples were collected from 70 locations over four weeks. The powder volume in the samples ranged from 0.2 to 58.6 g/m2 depending on the location and The particles got smaller with distance from the Sahara Desertbecause the heaviest and largest particles are deposited first, while the wind carries the smallest and lightest material farther.
Powder composition varies with distance
The composition of the powder also changed with distance, because ferrous particles deposited preferably closer to the original source, so the particles analyzed in the Pyrenees had 11% iron. This rate was reduced to 2% in the Swiss Alps, located further north.
Dust accumulation in icy and snow-covered environments can be detrimental to these ecosystems because white causes the environment to darkenresults in negative albedo feedback. This is because darker colors absorb solar radiation from space and therefore heat the surrounding environment, causing snow to melt. The same thing happens when wearing black clothing, which causes more heat in the summer, compared to white clothing that reflects the heat and keeps the wearer cooler.
As an example, a dust event in 2018 caused the annual snow cover to decrease by up to 30 days.
Cesium, beryllium and lead
Also, the haze in February 2021 caused many media outlets to publish that the dust brought radionuclides (a chemical element that emits radiation as it decomposes). French nuclear weapons tests in the Sahara in the 60s.
The researchers confirmed this statement by analyzing it. detected an increase in this element in samples of cesium and the Pyrenees. They also confirmed an increase in short-lived radionuclides. beryllium and leadIt’s often linked to radioactive fallout, so these elements have been deposited on the ground through recent snowfalls containing atmospheric dust, they explained.
But, plutonium abundances were not significantly different from background levels Those registered in the northern hemisphere as a result of nuclear tests of the USA and the USSR in the 50s and 60s.
Dumont and colleagues suggest that, due to the use of different fuels and engines, the nuclear footprint of this plutonium may differ from that resulting from French nuclear tests in the Sahara in the 1960s. The cesium and lead signatures measured in the Sahara are also the global results of these US and USSR tests, not the French.
Scientists remember that the French nuclear tests had only 0.017% of the strength of the nuclear projects of the USA and the USSR.
The article authors say more work needs to be done to determine how the expected increased frequency of these dust events in the future may affect water supplies, snow and ice melt and flow, avalanche hazards and the management of ski resorts.
Reference work: https://essd.copernicus.org/articles/15/3075/2023/
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