A source of radioactive plutonium has been discovered in Sahara dust: scientists have finally identified it (photo included).

Occasionally, the Sahara Desert, located in North Africa, stirs up a storm and spreads clouds of dust across Europe and other parts of the world. It is both intriguing and concerning that this sand still carries radioactive isotopes from atomic bomb tests conducted during the Cold War. However, a new study has revealed that the situation is not quite as previously believed, according to IFLScience.

In this new research, a team from the Laboratory of Climate and Environmental Sciences in France focused on understanding whether significant amounts of radioactive isotopes resulting from these tests were transported to Western Europe during a powerful dust event in the Sahara in March 2022. The findings suggest that radiation is still present in the dust that reached Europe three years ago. Interestingly, the radiation did not originate from the expected source.

Between 1960 and 1966, France conducted tests in the Algerian Sahara, which was under colonial control until 1962. Researchers note that this part of the desert was considered an ideal site for nuclear weapon testing due to its vast and sparsely populated nature.

Despite claims that bombs would be dropped in uninhabited areas, thousands of local residents and French soldiers were exposed to radiation. Open data indicates that up to 60,000 Algerians were affected by the explosions, though the French Ministry of Defense asserts that the number of affected individuals is half that — around 27,000 people.

According to lead author of the study, Yanzyunjie Xu-Yan, he and his colleagues discovered something intriguing: the radioactive isotopes found in the dust from the Sahara that reached Europe in 2022 originated from nuclear tests, but not from France as previously thought; rather, they came from the USA and the USSR.

It is important to note that the USA and USSR did not conduct tests in the Sahara, but their extensive testing during the Cold War left a significant radioactive footprint — which extended even to the desert. The study authors highlight that the yield of the French tests was only 0.02% of the total yield from the USSR and USA between 1950 and 1970.

It is known that most nuclear weapon tests by the USA and USSR were conducted at the same latitude as southern Algeria, but their debris could reach heights of 8,000 meters and then disperse over vast areas.

The team reached these conclusions by studying 53 samples of Sahara dust that arrived in Europe in 2022. The scientists analyzed the samples and found that the radioactive dust originated from the Reggane region in Algeria; however, the levels of plutonium in it did not match the low isotopic ratios below 0.07 from French nuclear tests. Instead, with a median ratio of 0.187, the samples aligned with American and Soviet test signatures.

Fortunately for Europeans, the levels of radiation in the Sahara dust reaching Europe are significantly below the safety thresholds set by the European Union. Scientists assert that they are unlikely to exceed the background radiation found in the soil. According to Xu-Yan, the actual risk is quite minimal.

It is worth noting that in Europe, the surface soil often has the same radioactivity as the dust that arrived from the Sahara in 2022.