The nuclear tests conducted by the United States and the then USSR (present day Russia) during the Cold War-era have left signatures that can still be traced.
The most recent example of their signatures being detected was during the dust cloud that that blanketed Europe in March 2022. The dust cloud had its origins in the Sahara desert.
A recent study conducted by the researchers from Paris-Saclay University in France has come to this conclusion.
However, the only solace is that researchers also concluded that the radioactivity detected during the Saharan dust cloud was way down below levels that are thought to be unsafe for humans.
Nonetheless, the study is an eye-opener for the long periods of time the nuclear fallout can continue to prevail in our environment.
Origins of the Saharan dust cloud
The study states that the Sahara Desert and the Sahel region in North Africa supply 50 to 70 percent of global dust sources.
Earlier it was thought that these dust particles may carry radioactivity which was due to the French nuclear weapon tests conducted in the early 1960s in Southern Algeria.
In March 2022, a citizen participative science campaign was launched through social media platform X (formerly Twitter). The campaign urged citizens to capture samples of the Saharan dust cloud, and 110 of them were collected from six western European countries – namely Austria, Belgium, France, Germany, Luxembourg, and Spain.
The researchers selected 53 of the total 110 samples received from citizens based on particle size distribution and sampling date.
How the nuclear signature’s origins was traced
As per the researchers, however, while the dust was from South Algeria its signature did not match the strength of the French nuclear tests – and it was more related to the Cold War-era testing done by the US and then USSR.
“Plutonium isotopic signatures, a unique nuclear bomb fingerprint, remained in the range of the global fallout signatures largely dominated by US and former USSR nuclear tests, significantly different from French fallout signature,” write researchers.
In conclusion, radionuclide signatures detected in Saharan dust collected in 2022 remained in the range of the global fallout found as a background signal in soils worldwide, and they significantly differed from the characteristics of the French atmospheric nuclear tests conducted in Southern Algeria, the paper says.
The first nuclear testing was conducted on July 16, 1945, at a desert test site in New Mexico when the United States exploded its first atomic bomb. From that day onwards over 2,000 nuclear tests were conducted underwater, in the atmosphere, and underground by the US, USSR, and other countries.
As per a United Nations report, the US alone conducted 1,032 nuclear tests between 1945 and 1992. USSR is second on the list with 715 tests conducted between 1949 and 1990. France comes third with 210 tests, and China along with the UK conducted 45 tests each.
The nuclear tests by the US and Russia stopped with the opening for signature of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) in 1996.
Since the CTBT was opened, only 10 nuclear tests have been reported so far – with India and Pakistan carrying out two each, and North Korea conducting the remaining.
