November 11, 2011

expert reaction to IAEA measurements of iodine 131 in the Czech Republic

The International Atomic Energy Agency detected levels of radioactive iodine-131 in the Czech Republic.

Prof Jim Smith, Reader in Environmental Physics at the University of Portsmouth, said:

“The Czech authorities appear to have ruled out a nuclear reactor as the source of I-131 (presumably because no other radioactive isotopes have been detected at the same time), so the source is likely to be I-131 used in radiation therapy, or the production of this isotope. The amounts of I-131 detected appear to be at very low levels, but, given that other locations in Europe are also apparently reporting this to the IAEA, I would be surprised if this was due to a “routine” radioactive release. I am sure that the IAEA will be keen to track down the source of this release – perhaps a hospital or radioisotope production site.”

Prof Malcolm Sperrin, Director of Medical Physics at Royal Berkshire Hospital and Fellow of the Institute of Physics and Engineering in Medicine, said:

“The detection of I131 may not be such a surprise in a developed economy where this isotope may be used for imaging or therapy. The amount or concentration of the isotope is not stated but the response of the competent authorities suggests that the risk is vanishingly small. The fact that it is reported at all may be an indication of the sensitivity of the environmental measuring stations and the current interest in the aftermath of Fukushima.

“There may be concern by some that the detection of iodine has an origin in the Fukushima complex especially since the recent announcement of iodine in that complex suggesting the presence of fission products. However, if an estimate of the distance between Fukushima and the Czech Republic is 8000 miles, and an average wind speed of 30 miles per hour then there is a transit time of 12 days or a little less than two decay half-lives. This with atmospheric dispersion means any link between Fukushima and the reported detection is extremely unlikely.

“It is far more likely that the iodine may be as a result of excretion by patients undergoing medical treatment. Whilst such patients are carefully controlled, some release of iodine into the environment may be inevitable but would certainly be well below any limits where health detriment would even begin to be an issue for concern.”