In October 2017, most European countries reported unique atmospheric detections of aerosol-bound radioruthenium (106Ru). The range of concentrations varied from some tenths of µBq·m−3 to more than 150 mBq·m−3. The widespread detection at such considerable (yet innocuous) levels suggested a considerable release. To compare activity reports of airborne 106Ru with different sampling periods, concentrations were reconstructed based on the most probable plume presence duration at each location. Based on airborne concentration spreading and chemical considerations, it is possible to assume that the release occurred in the Southern Urals region (Russian Federation). The 106Ru age was estimated to be about 2 years. It exhibited highly soluble and less soluble fractions in aqueous media, high radiopurity (lack of concomitant radionuclides), and volatility between 700 and 1,000 °C, thus suggesting a release at an advanced stage in the reprocessing of nuclear fuel. The amount and isotopic characteristics of the radioruthenium release may indicate a context with the production of a large 144Ce source for a neutrino experiment.

The atmospheric nuclear testing in the 1950s and early 1960s and the burn-up of the SNAP-9A satellite led to large injections of radionuclides into the stratosphere. It is generally accepted that current levels of plutonium and caesium radionuclides in the stratosphere are negligible. Here we show that those radionuclides are present in the stratosphere at higher levels than in the troposphere. The lower content in the troposphere reveals that dry and wet deposition efficiently removes radionuclides within a period of a few weeks to months. Since the stratosphere is thermally stratified and separated from the troposphere by the tropopause, radioactive aerosols remain longer. We estimate a mean residence time for plutonium and caesium radionuclides in the stratosphere of 2.5-5 years. Our results also reveal that strong volcanic eruptions like Eyjafjallajökull in 2010 have an important role in redistributing anthropogenic radionuclides from the stratosphere to the troposphere.

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Discovery of radioactive radium contaminations in a former landfill site in Biel was made in 2014. Following this, it was decided to search for and remediate sites that had possibly been contaminated with radium as a result of its use in the watchmaking industry between 1920 and 1960. This work describe the general approach to identify survey and remediate affected sites. The methods is based on the concept of existing exposure situations as developed by the International Commission on Radiological Protection, and is supported by an action plan for radium 2015-2019 approved by the Federal Council in 2015. The plan comprises four steps: the search for potentially contaminated sites, the measurement and assessment of each site, the remediation of those sites where the public would be exposed to an annual dose higher than 1 mSv, and actions to secure the landfill sites. The arrangements for each step are described in the present article. The measurement and remediation procedures imply intrusions into the privacy of the inhabitants. This requires the public authorities to actively inform the population and to develop an effective and transparent means of communication. The actions developed for this are also described.