RADIATION levels across Europe have risen mysteriously – and Russia may be behind the baffling phenomenon.
German scientists say there has been a slight increase in a number of particles of the isotope Ruthenium-106 in Germany, Italy, Austria, Switzerland, and France.
The low levels of the stable isotope do not pose a threat to human health, the Office of Radiation Protection said, but the mysterious rise has baffled them.
Ruthenium-106 is used in chemotherapy to treat eye tumors and is also used in radioisotope thermoelectric generators (RTGs), which power satellites.
The spike could not have come from a nuclear accident, experts added.
The Office for Radiation Protection said: “New analyses of the source of the radioactive material are likely to indicate a release in the southern Ural, but other regions in Southern Russia cannot be excluded.
“Since only ruthenium-106 has been detected, an accident in a nuclear power plant can be excluded as a cause.
“The origin of the measured ruthenium-106 is still unknown. By declaring the spread of radioactive substances in the atmosphere can be limited the areas in which the release could be.”
In February it was reported that dangerous radioactive particles were detected in seven different European countries.
Traces of Iodine-131 were found in Norway, Finland, Poland, Czech Republic, Germany, France and Spain in January, but the public was not immediately alerted.
These radioactive particles are produced by atomic bomb explosions or nuclear disasters such as Chernobyl or Fukushima.
They appear to have come from Eastern Europe, but experts have not been able to say exactly what produced them.
In 2012 the International Atomic Energy Agency reported that RTGs were successfully removed from the Baltic Sea in Russia.
These RTGs contained extremely powerful strontium-90 radioactive sources to provide energy for lighthouses along the Russian coast of the Baltic Sea.
Ninety-three Baltic RTGs were located in remote areas along the coastline without sufficient physical protection of their powerful radiation sources. Therefore they posed a potential risk to people and the environment.