IAEA's press release mentions only Czech Republic and other areas in Europe.
According to NHK News (11/12/2011), CTBTO says Russia, Sweden, and Austria.
NHK adds Hungary and Germany.
IAEA says it is probably not from a nuclear power plant accident, and it is not from Fukushima, and it doesn't affect health because the amount is minute.
If CTBTO stations have been catching it, iodine-131 is airborne; you can't say someone treated for thyroid illness is peeing.
NHK News speculates the origin of this artificial iodine as follows:
Radioactive iodine-131 does not exist in nature. It is caused by nuclear fission of materials like uranium. When a serious accident happens in a nuclear facility, iodine-131 may be released into the environment. In the Chernobyl nuclear plant accident that took place in the former Soviet Union, a large amount of iodine-131 was released, causing grave health damage to the residents who were exposed to the nuclide. Iodine-131 was released in the Fukushima I Nuclear Power Plant accident. Iodine-131 is also used in the medical purposes like diagnosis and treatment. Hospitals, laboratories and corporations are responsible for the safe management of the radioactive materials including iodine-131 for medical and research purposes, there are cases reported of inappropriate management.
... meaning some hospital, lab, or manufacturer has been releasing iodine-131 by accident or by neglect, according to the insinuation of IAEA and NHK.
OK, so where is it coming from? IAEA says there is no health effect. (Paging Mr. Edano...)
Well, there was an earthquake that hit Turkey on October 23. There was a report/rumor on the Iranian state radio in Japanese that the "most dangerous in the world" Metsamor Nuclear Power Plant in Armenia was damaged in the earthquake. But if the CTBTO station in Austria started detecting iodine-131 on October 17 (1 nanosievert/hour max, 1/100 of the level seen after the Fukushima accident), the Armenian plant cannot be it.
IAEA's press release (11/11/2011):
The IAEA has received information from the State Office for Nuclear Safety of the Czech Republic that very low levels of iodine-131 have been measured in the atmosphere over the Czech Republic in recent days.
The IAEA has learned about similar measurements in other locations across Europe.
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.
Iodine-131 is a short-lived radioisotope that has a radioactive decay half-life of about eight days.
The IAEA is working with its counterparts to determine the cause and origin of the iodine-131.
The IAEA will provide further information via its Website as it becomes available.