Detector network flags traces of radioactive iodine in Europe

Small amounts of iodine-131, well below levels likely to have any effect on human health, were detected in outdoor air last month in a number of European countries. The source of the release has yet to be identified.

According to a preliminary report from France's Institute for Radiological Protection and Nuclear Safety (IRSN), I-131 was first detected in northern Norway during the second week of January. It was also detected in Finland, Poland, Czech Republic, Germany, France and Spain during the remainder of the month.

IRSN noted that only particulate iodine was detected. "When detectable, gaseous iodine is usually dominant and can be estaimated to be three to five times higher than the fraction of particulate iodine," it said.

Particulate Iodine-131 (value +/- uncertainty) in the atmosphere (µBq/m3) (Image: IRSN)

The highest concentrations - 5.92 micro-becquerels per cubic meter (µBq/m3) - were measured in Poland, but even those are far lower than concentrations that might have any effect on human health.

As I-131 has a half-life of about eight days, IRSN concludes, "The detection of this radionuclide is proof of a rather recent release." However, the source of the iodine remains unknown.

IRSN said the data has been shared between members of the so-called Ring of Five - an informal European network of experts from organisations involved in the radiological surveillance of the atmosphere. The network - set up in 1983 - now has 110 aerosol collection sites across Europe and almost 90 experts, four of whom are from IRSN.

Iodine-131 is commonly used to diagnose and treat thyroid cancer. It is also used to treat non-malignant thyroid disorders and in diagnosis of abnormal liver function, renal (kidney) blood flow and urinary tract obstruction.

Most I-131 production is from nuclear reactor neutron-irradiation of a natural tellurium target.

In late October last year, a small amount of radioactive iodine was released into the environment during an incident involving the handling of test fuel in the reactor hall of the Halden research reactor in Norway.

Researched and written
by World Nuclear News