An aerosol particle containing uranium-235 and found in the atmosphere over the Aleutian Islands (Alaska), arose from a radiation leak in Asia. Scientists from the National Oceanic and Atmospheric Administration of the United States write about this in an article published in the Journal of Environmental Radioactivity. The research is briefly described by the Gizmodo edition.
Uranium-235 is a radioactive isotope that is used as nuclear fuel or in nuclear weapons. Scientists have never found this nuclide in atmospheric aerosols, so they deny the possibility of the particle originating from a natural source.
The researchers believe that the leak was caused by a violation of the storage conditions of the enriched uranium, when radionuclides were released into the atmosphere. Wind direction data points to Asian countries such as China and North Korea. Since the leak occurred recently (it was discovered in 2016), this rules out the 2011 accident at the Japanese nuclear power plant "Fukushima-1" as a possible source.
The uranium-235-enriched particle is not dangerous, the researchers said. The source of the radionuclides is small and most likely not a threat either.
In September 2017, an increase in the level of ruthenium-106 isotope in the atmosphere was recorded in Germany, Italy, Austria, Switzerland and France. The Federal Office for Radiation Protection of the Federal Republic of Germany noted that this does not threaten human health. The source of infection was named the release of a radionuclide in the Chelyabinsk region.