In early January, minute amounts of radioactive iodine-131 were detected in the atmosphere over the Svanhovd, Norway air monitoring station very close to the border with the Russian Kola peninsula. The next observation was at Rovaniemi in Finnish Lapland. Since then, I-131 has been detected by air quality monitoring stations above other countries in Europe including Finland, Poland, Czechia (Czech Republic), Germany, France and Spain.
The concentration of I-131 that has been detected is very small and currently not a threat to human health. The detection of the I-131 was not reported until February by the French Institute for Radiological Protection and Nuclear Safety, with European news outlets saying that since the levels detected were so low, they did not believe that the findings were "newsworthy."
Finland’s Radiation and Nuclear Safety Authority (STUK) decided to follow the French example and posted a press release about the increased levels of radioactivity. "At Svanhovd, measurements in the period January 9-16 show levels of 0,5 micro Becquerel per cubic meter air (µBq/m3). In France, where authorities decided to publish the information, measured radioactivity was much lower, from 0,1 to 0,31 µBq/m3. Levels measured in Finland were also lower than in northern Norway with 0,27 µBq/m3 measured in Rovaniemi and 0,3 µBq/m3 in Kotka."
The half-life of I-131 is only eight days which means that in order to be detected, the I-131 must have been created very recently. With the changing wind patterns caused by recent rough weather over Europe, it has been difficult to pin down where the I-131 came from. The Norwegian Radiation Protection Authority said that the I-131 was most likely released somewhere over eastern Europe. The U.S. has flown WC-135 nuclear explosion 'sniffer' aircraft over Europe in an attempt to identify the source of the I-131 but has been unsuccessful.
I-131 is regularly found following the test of nuclear bombs. Since the first detection of the I-131 was in northern Norway close to Russia, there is speculation that the Russians have been secretly testing nuclear weapons. They are in the process of upgrading their nuclear arsenal and I-131 is released when uranium bombs are detonated. However, the lack of other isotopes that are created in nuclear detonations makes such a source unlikely. This lack of other radioactive isotopes also makes it improbable that the I-131 was released from a nuclear power plant.
Because the I-131 was found alone, that would mean that it would have to have to been recently generated and purified. Pure I-131 is used in medical procedures. There are theories that a pharmaceutical firm has suffered some sort of accidental release and has not reported it.
In 2011, there was an incident where I-131 was reported over several European countries for a few weeks. Authorities were also unable to identify the source for that I-131until last week when a report was issued that identified the source of the I-131 as faulty filters at the Institute of Isotopes Ltd in Budapest, Hungary, a facility which manufactures radioactive isotopes for medical use.
Graphic from French Institute for Radiological Protection and Nuclear Safety:
