The International Atomic Energy Agency (IAEA) says that low levels of a radioactive isotope have been detected in several European countries in the past few days, but the source of the emission is unknown.
The Vienna-based agency said on November 11 that it 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."
The Vienna-based body said iodine-131 was a short-lived radioisotope with a radioactive decay half-life of about eight days.
Meanwhile, the Czech nuclear security authority said it has detected radioactive iodine-131 at a number of monitoring stations since late October.
It said the source of the contamination was "most probably" outside the Czech Republic, and that its information suggested the cause was not an accident at a nuclear power plant.
Poland, Slovakia, and Austria also said that they had detected abnormal but still very low levels.
compiled from agency reports