VIENNA Very low levels of radioactive iodine-131 have been detected in Europe but the particles are not believed to pose a public health risk, the U.N. nuclear agency said on Friday, eight months after Japan's Fukushima disaster.
The International Atomic Energy Agency (IAEA), the Vienna-based U.N. watchdog, said it was seeking to determine the source but that it was not believed to come from Japan's stricken Fukushima nuclear plant after its emergency in March.
The Czech Republic's nuclear security authority said the source was not believed to be in the country and was not believed to be from a nuclear power plant. It said it could possibly be from the production of radiopharmaceuticals.
Hungary, Slovakia and Austria also reported the detection at very low levels, saying it did not pose a health risk to their populations.
Iodine-131, linked to cancer if found in high doses, can contaminate products such as milk and vegetables.
Paddy Regan, a professor of nuclear physics at Britain's University of Surrey, said the suggestion that it may have leaked from a radiopharmaceuticals maker "sounds very sensible and totally reasonable."
He said since iodine was used in the treatment of thyroid conditions it was also likely that hospitals in many European countries would have it in their stores.
"It would be very unlikely for it to have come from Fukushima since the accident was so many months ago and iodine-131 has a brief half-life," he said.
The IAEA said the Czech Republic's nuclear safety body had informed it that "very low levels" of iodine-131 had been measured in the atmosphere over the country in recent days.
"The IAEA has learned about similar measurements in other locations across Europe," the brief statement said.
"The IAEA believes the current trace levels of iodine-131 that have been measured do not pose a public health risk and are not caused by the Fukushima Daiichi nuclear accident in Japan," it added.
"The IAEA is working with its counterparts to determine the cause and origin of the iodine-131."
Iodine-131 is a short-lived radioisotope that has a radioactive decay half-life of about eight days, the IAEA said.
The Czech watchdog said it had detected iodine-131 at a number of monitoring stations since late October. It said there was no health risk from the iodine.
"It was detected by our radiation monitoring network, with probability bordering on certainty the source is abroad. It is iodine-131 and we have asked the IAEA if they know what the source could be," Czech State Office for Nuclear Safety chief Dana Drabova told Reuters.
The IAEA said it did not know the source of the iodine-131 and would give more details when available. It did not give details of other locations in Europe where levels had been detected.
Officials in Spain and Ukraine said they had not detected any abnormal radiation levels and Romania's watchdog said there had been no incident at the country's sole nuclear plant.
Austria's Environment Ministry said small levels were measured in the east and north of the Alpine country, saying the estimated dose level for the population was one 40,000th of the dose of radiation received in a transatlantic flight.
"At these levels we can absolutely rule out a health risk to the Austrian population," it said late on Tuesday.
In the world's worst nuclear accident since Chernobyl in 1986, an earthquake followed by a massive tsunami overwhelmed the Fukushima plant in Japan, causing a reactor meltdown and leakage of radiation, including of iodine.
In the days and weeks after the accident, tiny amounts of iodine-131 believed to have come from Fukushima were detected as far away as Iceland and other parts of Europe, as well as in the United States.
(Additional reporting by Kate Kelland in London, Radu Marinas in Bucharest, Fiona Ortiz in Madrid, Olzhas Auezov in Kiev; Writing by Sylvia Westall; Editing by Janet Lawrence)