Norway, nuclear radiation recorded in Tromsø: origin unknown

OSLO. At the end of March, the Norwegian Radioactive and Nuclear Safety Authority measured very low levels of radioactive iodine (l-131) in Tromsø. The measurement took place in week 12, March 21 to 26, at a filter station of the air. The Barents Observer first reported the case.

What is iodine 131?
Each element has atoms with a specific number of protons in the nucleus, and these atoms comprise a mixture of a few different isotopes, each with a specific number of neutrons. Iodine has an atomic number of 53, which corresponds to 53 protons in its nucleus. On average, natural iodine also has 74 neutrons, for a total of 127 nuclear particles (53 protons + 74 neutrons). Iodine-131 is a radioactive isotope with 131 nuclear particles, i.e. 53 protons and 78 neutrons.

Radioactive isotopes are unstable and decay at a certain rate, emitting radioactive radiation. The rate of decay can easily be described by the half-life, which is the time it takes for half of the original radioactive isotopes to disappear. The half-life of iodine 131 is approximately eight days. Therefore, after one, two and three half-lives (i.e. 8, 16 and 24 days), 50%, 25% and 12.5% ​​of the original amount of iodine-131 remain, respectively. The intensity of the radiation also decreases correspondingly.

The damage to humans
Iodine is an element that accumulates in the body's thyroid gland. This produces cells that lower the calcium content in the blood. Absorption of radioactive iodine increases the risk of cancer and this has been confirmed by emissions from the Chernobyl and Fukushima reactors.

The facts
According to the Management, the concentrations measured do not represent a risk for humans or the environment. The source of the release is currently unknown. According to the Directorate, there are several measuring stations throughout Norway, which are continuously monitored for radioactivity in the air. Bredo Møller, an engineer at the Directorate in charge of air monitoring, says that this is not an unusual phenomenon and that it is the first time something like this has been detected this year.

It is also the first time that something like this has been detected at the Tromsø station, which was established last year. These are very low levels, but still sufficient to carry out this type of detection, far from those dangerous for humans and the environment.

Møller says they are working to find out where it came from. «Only one radioactive substance was detected, this indicates that there was no accident at a nuclear power plant or similar. If that had been the case, we would have recorded other material too as such events would cause the release of many other isotopes, such as strontium-90 and cesium-137. However this iodine will decay completely within a few days. The University Hospital of Northern Norway, which carries out cancer diagnosis and treatment, could be an explanation for the phenomenon,” says Møller.

«We have looked at the weather forecasts and are in contact with other Nordic countries doing the same kind of monitoring» continues Møller, who believes there is nothing to worry about.