Radioactive Plutonium In Sahara Dust Came From An Unexpected Source

In a new study, scientists have investigated whether substantial amounts of radioactive isotopes generated by these tests were transported to Western Europe amid a powerful Saharan dust event in March 2022. They discovered that radiation still lingers in the dust that reached Europe – but not from the source they expected.

Between 1960 and 1966, France detonated 17 bombs in the Algerian Sahara, which was under their colonial control until they gained independence in 1962. With its vast, sparsely populated landscape, it was considered an ideal location for nuclear weapons testing.

Despite claims the bombs would be dropped in an unpopulated region, thousands of locals and French soldiers were exposed to radiation. The most severe estimates suggest that up to 60,000 Algerians were impacted by the blasts, while the French Ministry of Defense argues it’s closer to 27,000 people.

Oddly, though, the new study found that the radioactive isotopes present in the Sahara dust that reached Europe in March 2022 originated from nuclear tests conducted by the USA and the USSR, not France. 

Although the USA and USSR did not conduct tests in the Sahara, the prolific nature of their nuclear tests during the Cold War left a widespread radioactive imprint detectable even in Saharan dust.

“This is because the power of detonation of French tests is only 0.02 percent of the total power of detonation of USSR and USA between 1950 to 1970. Much of the USSR and USA nuclear weapon tests were realized at the same latitude of South Algeria, and the debris of these tests can reach 8,000 meters [26,000 feet] high and be dispersed by wind very quickly at a global level,” Yangjunjie Xu-Yang, lead study author from the Climate and Environment Sciences Laboratory in France, told IFLScience.

The team reached these conclusions by studying 53 samples from the March 2022 Saharan dust event and looking for the presence of specific radioactive isotopes.

The results suggest that the radioactive dust originated in Algeria’s Reggane region, but its plutonium levels didn’t match the low isotopic ratios (below 0.07) from France’s nuclear tests. Instead, with a median ratio of 0.187, the samples aligned with US and Soviet test signatures – a conclusion further supported by cesium isotopic analysis.

But fear not: Reassuringly, the levels of Saharan dust radiation reaching Europe remain well below the European Union’s safety thresholds and are unlikely to be significantly higher than the background radiation found in soil.

“Based on my findings, the risk is negligible,” added Xu-Yang.

“In Europe, the surface soil often has radioactivity in the same order of magnitude as the Saharan dust analyzed in our study. Saharan dust outbreak is a serious problem and causes high levels of atmospheric pollution, but this pollution is not associated with the radioactivity of the dust. Policymakers should be proactive in addressing the issue of the atmospheric pollution caused by Saharan dust but the public should be informed that this pollution is not related to the radioactivity of the dust at all,” he continued. 

The new study is published in the journal Science Advances.