Unusual Radiation Detected in Europe (Updated)

The International Atomic Energy Agency is reporting low levels of unusual radiation detected in the atmosphere over the Czech Republic and other countries. (Story here). The radiation detected is iodine-131.

From Wikipedia:

Iodine-131 ... is an important radioisotope of iodine. It has a radioactive decay half-life of about eight days. Its uses are mostly medical and pharmaceutical. It also plays a major role as a radioactive isotope present in nuclear fission products, and was a significant contributor to the health hazards from open-air atomic bomb testing in the 1950s, and from the Chernobyl disaster, as well as being a large fraction of the contamination hazard in the first weeks in the Japanese nuclear crisis. This is because I-131 is a major uranium, plutonium fission product, comprising nearly 3% of the total products of fission (by weight).

There is no word on the source--although it most likely is from a nuclear fission source--but it is notable that Iodine-131 only has a half-life of 8-days, so whatever the origin, it was probably not too long ago.

Update: Still no word on its source, but some more information as to where the radiation has been detected.

Update: Radiation detected in Hungary.