ANALYSIS: European radiation safety agencies detect traces of iodine-131 in air, source of leak unknown

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Publish date: November 17, 2011

Written by: Andrey Ozharovsky

Translated by: Maria Kaminskaya

Radiation safety agencies in the Czech Republic, Austria, Sweden, and other European countries report traces of iodine-131 in the atmosphere – an indication of either a radiation leak or a severe accident at a nuclear facility. The International Atomic Energy Agency (IAEA) asserts no risk to population health, but the lack of reliable data on specific concentrations or locations where the radionuclide was detected suggests safety might be a concern.

Radioactive iodine found over the Czech Republic

On November 11, the IAEA issued a press release stating that “low levels” of radioactive iodine-131 – an artificial radionuclide produced as a result of nuclear fission – was detected in the atmosphere above the Czech Republic and other European countries.

“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 press release said.

The brief statement leaves much room for speculation. It makes no mention of specific iodine-131 concentrations – information that would be necessary to try to establish the source of origin or the implied risks.

When asked about more specific data, a press service representative with the IAEA told Bellona in a telephone conversation that the agency does not itself perform measurements, but rather collects and makes available information supplied by relevant authorities within its member states.

The IAEA’s November 11 press release said the agency was “working with its counterparts to determine the cause and origin of the iodine-131.”

The statement also said 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” – two points that have been consistently reiterated in statements regarding similar recordings of atmospheric contamination that came this week from several radiation safety agencies in Europe.

A Reuters report of the same date said, citing expert sources, that “the origin of the radiation –which has been spreading for about two weeks – remained a mystery but could come from many possible sources ranging from medical laboratories or hospitals to nuclear submarines.”

The findings of Czech and Austrian authorities

A search across the websites of a variety of European-based nuclear and environmental agencies and organisations has proven a challenge since a lot of the resources publish information in national languages with no English translation made available.

In the Czech Republic, the State Office for Nuclear Safety issued the following short statement (in Czech) on its website, informing the public of “trace amounts” of radioactive iodine found in the atmosphere over the country. A Google translation allows one to infer that measurements undertaken as part of routine monitoring in the past two weeks have established the presence of trace amounts of iodine-131 in very low concentrations at micro-becquerel-per-cubic-metre levels in aerosol and gaseous form.

The statement also says, judging from its automatic translation, that the origin of the source of contamination is unknown, though unlikely to be situated within the Czech Republic, and that no increase has been recorded in concentrations of other artificial radionuclides, which leads the agency to suggest that this is not the result of an accident at a nuclear power plant.

The Czech Republic operates two nuclear power plants, with altogether six reactors – two VVER-1000 models at Temelin and four VVER-440s at Dukovany, all six of Soviet design.

The Austrian Federal Ministry of Agriculture, Forestry, Environment, and Water Management also spoke of “tiny” amounts of radioactive iodine-131, which were recorded by air quality monitoring stations in the country’s east and north, in this statement (in German) on its website, as translated by Google. Measurements of caesium-137 and other radioactive substances are within the normal ranges, the statement also said, in its Google translation.

bodytextimage_Austria2.jpg Photo: Карта WANO

Basing its conclusions on information supplied by monitoring laboratories in other countries, the Austrian authority, according to its statement’s Google translation, rules out with certainty the possibility that the contamination could have originated within Austria, placing the likely source somewhere east or southeast of the country.

This would point in the direction of Slovakia, which operates altogether four commercial nuclear reactors – two at Bohunice (the other two built at the site were shut down as a condition of Slovakia’s accession to the European Union) and two at Mochovce – or Hungary, which runs four reactors at Paks Nuclear Power Plant. All eight are of the Soviet-designed VVER-440 series.  

Other European agencies confirm low contamination levels

As for Hungary, the website of the Budapest-based National Association of Radio Distress-Signalling and Infocommunications’ (RSOE) Emergency and Disaster Information Service has an event report of November 12, which says, in part:

“Hungary detected a very minimal increase in radioactive iodine-131 at two monitoring stations last week but the levels registered do not pose a public health risk, the head of the Hungarian Radiobiology Research Institute said on Friday.”

The report then quotes Dr Geza Safrany, director of the institute, as saying that a very minimal increase in activity was registered in Hungary on November 5,  “… but this is far below the levels found after Fukushima.” According to Dr Safrany, the increase was registered at monitoring stations in the capital Budapest and the eastern town of Miskolc.

The report also quotes Dr Safrany as saying the source cannot at the time being be determined, but that it “certainly does not pose a health risk.” Further citing Dr Safrany, the report said it was “unlikely Hungary would be the source of the leakage as it was detected in several places in Europe.”

Reuters on November 11 also reported that “Germany’s Environment Ministry said slightly higher levels of radioactive iodine [were] measured in the north of the country, ruling out that it came from a nuclear power plant.”

In Poland, a spokesman for the atomic energy agency told AFP in this recent story that “trace levels of radioactive iodine-131” were detected over Poland in measurements taken between October 17 and October 24.

The Polish official, Stanislaw Latek, added that Ukraine had also detected “trace levels” between October 10 and October 20, according to AFP.

The news agency reported that in Slovakia, Vladimir Jurina from the public health authority said levels of iodine-131 were “just about measurable levels.”

As of November 15, the Russian press also carried reports saying similar statements came from France, where trace concentrations of iodine-131 just above measurable quantities were detected in the atmosphere.

All such reports from European radiation safety agencies say they will continue to monitor the situation and try to establish the source. They consistently rule out any connection with the nuclear and radiation disaster at Japan’s Fukushima, where efforts to bring the crisis under control are still ongoing.

The dispersion pattern mystery

But where Austria and the Czech Republic, as well as Germany, Poland, Hungary, and Slovakia are all immediate neighbours – meaning that readings of trace concentrations of iodine-131 in their atmosphere could theoretically signal a leak at one of the nuclear power plants or other nuclear or radiation-related facility in the area, this November 11 statement (in Swedish) on the website of the Swedish Radiation Safety Authority compounds the holding mystery as to the original source of contamination.

Across the Baltic Sea in Northern Europe, the Swedish agency reports of measurements of “slightly elevated levels” of iodine-131 received from other authorities in Europe, but adds that similarly elevated readings were recorded by Sweden’s own Defence Research Agency.

Poland’s Latek told AFP that “unconfirmed reports suggest there may have been an incident at a nuclear power station in Pakistan but this requires further confirmation.”

On October 19, according to AFP, authorities in that Middle Eastern state “reported an emergency at the almost 40-year-old Karachi nuclear plant […] when workers were forced to repair a leak.”

But a more recent AFP report cites an official from the Pakistani plant as saying “no radioactivity had been recorded and none of [the] staff had been affected.”

Russia’s environmentalist Yablokov: Something very unpleasant has happened

Even though some of the official statements place little value in the theory that a nuclear power plant is involved – experts in the Reuters story lean toward radiomedical sources – those with knowledge of the field who have lent their views to Bellona were not so quick to discard the possibility that an event at a reactor, commercial or otherwise, could be the potential cause of contamination.

“If even the IAEA has acknowledged elevated levels of iodine-131 not only over the Czech Republic but over other European countries as well, then it means something very unpleasant, and uncommon has happened,” the renowned Russian environmentalist and a corresponding member of the Russian Academy of Sciences, Professor Alexei Yablokov told Bellona in an interview.

Criticism is frequently levelled at the Vienna-based organisation for what some regard as a very conservative stance in both its information policies and the assessments it makes of the severity of nuclear and radiation-related events as well as their consequences for population health and environmental well-being. Statements where the IAEA grants specific attention to an issue – even as it may emphasise no risk to human health – would, then, presumably be an indication that the event in question deserves serious scrutiny.

Prof Yablokov also told Bellona that, from time to time, any nuclear power plant releases small concentrations of iodine-131 into the atmosphere.

“This is one of the major dangers of having a [nuclear power plant] nearby,” he said.

Other experts that Bellona has talked to agreed that either a serious accident has taken place or an emergency situation at a research or power-generating reactor that necessitated “venting” radioactive substances in the course of an “emergency discharge” into the atmosphere.

In Russia, the news about radioactive iodine-131 over several European nations was carried by a number of news agencies, including in a November 11 report by RIA Novosti (in Russian), which said that “iodine-131 is considered to be the most dangerous nuclide produced as a result of nuclear fission. This isotope triggers mutations and destruction of cells that it penetrates, as well as of surrounding tissues, to a depth of several millimetres.”

“Radioactive iodine is usually released into the environment as a result of nuclear tests or accidents at nuclear power plants,” the story said. “Its half-life period is eight days.”

According to Reuters, Russia is among those European countries that did not detect any abnormal iodine-131 levels.

A nuclear reactor remains the most likely source

It is at this point impossible to establish in which country or at which site the radioactive release occurred. But what would remain most likely is that the source of the radioactive iodine is either a commercial or research reactor.

Radioactive iodine-131 is not found in natural concentrations – it is an artificial beta-emitting nuclide which is present in products of uranium fission. For iodine-131 to appear in measurable quantities, it has to result from a chain reaction of uranium fission – something that takes place in nuclear reactors run at commercial nuclear power plants or research organisations.

And despite suggestions made that the concentrations detected in the atmosphere above Europe could have come from medical sources, a health institution that routinely uses radioactive iodine for medical or pharmaceutical purposes would hardly have enough of the substance for the leak to spread as wide as was recorded in measurements taken in countries that are thousands of kilometres apart.  

Accidents with significant releases of radioactive iodine-131 have taken places before, including in Russia.

One such major leak occurred on November 30, 1975, following a severe accident at Leningrad Nuclear Power Plant (in Russian) near what is now called St. Petersburg, formerly Leningrad. The concentrations were heavy enough to reach this Russian second largest city and were also picked up by monitoring stations in nearby Sweden and Finland.

In the summer of 1997, a research reactor at the State Scientific Centre Research Institute of Atomic Reactors (NIIAR), in the Central Russian city of Dimitrovgrad, was spewing radioactive iodine-131 (in Russian) into the atmosphere for three weeks, between July 25 and August 16. On some of the days during that period, the discharges exceeded the so-called sanctioned daily limit by 15 to 20 times.

The isotope iodine-131, which has a radioactive decay half-life of about eight days, is especially dangerous for the thyroid. As it is breathed in with the air, iodine-131 may be accumulated by the system and build up in the thyroid, where it undergoes beta-decay. This may result in severe damage to the thyroid and trigger oncological disease.

For this reason, iodine-131 presents one of the most significant health risks to the population that comes under threat of being exposed to radioactive fallout from a severe nuclear accident – such as the 1986 nuclear catastrophe at Chernobyl, which led to a dramatic increase in the rates of thyroid cancer observed in the populations residing in the affected regions in Belarus, Ukraine, and Russia.

The risk of exposure to iodine-131 has also been a major concern during the disaster at Fukushima, where multiple core meltdowns and containment ruptures led to massive releases of radiation, and tablets of stable iodine were distributed among the affected populations as one of the standard first-response measures to protect the thyroid gland.

The health factor

Given the scarcity of available information, the IAEA’s assertion that “the current trace levels of iodine-131 that have been measured do not pose a public health risk” seems to lack substantiation for two reasons.

First, the precise data on the concentrations detected in the European atmosphere, in becquerels per cubic metre of air, must be made available to rule out confidently any risk to population health.

Secondly, the very fact that radioactive iodine has been detected in the air above countries that lie as far apart as Sweden and Austria prompts one to suspect that the leak is of a rather substantial scope – meaning that the actual concentrations near the source, which is as yet to be established, would also be significantly higher and present a much graver health risk.

Prof Yablokov believes that radioactive iodine-131, regardless whether it may occur in very small concentrations, poses a danger to human health that cannot be ignored.

“However low the level of radioactive iodine may be in the atmosphere, it is dangerous. Especially for children, whose thyroids absorb iodine very quickly, and then accumulate it,” Prof Yablokov told Bellona. “Don’t believe the nuclear authorities’ soothing words! Iodine-131 remains dangerous not just for eight days, but for ten half-life periods – around eighty days. And eighty days is enough for the concentration of iodine to increase in the thyroid.”

Even small quantities of radioactive iodine in the atmosphere carry sufficient risk of increasing the likelihood of cancer and other disease of the thyroid. Furthermore, radioactive iodine-131 may accumulate in food products such as milk and vegetables, which adds to the overall risk of exposure.

Given the two or so weeks that the radioactive cloud has hung over the Czech Republic and that enough of it was released by a source that is yet to be discovered and contained to have reached Sweden, the threat holds that the radioactivity could spread toward Eastern Europe and Russia.

For the time being, what precisely has happened and how high the actual risks are to the population will need to be determined as more details become available.