Abstract Radon ( 222 Rn) has been highlighted by a number of authors as a significant public health concern. For example, it is the second most significant cause of lung cancer after tobacco smoking ( c. 1000–2000 and 21 000 deaths per year in the UK and USA, respectively), yet a very high proportion of the general public appears to be unaware of the risk. This chapter deals with topical radon issues, such as: radon in the workplace; radon in homes; exposure to radon during leisure activities; radon and water; measurement and monitoring; seasonal correction; remediation; cancer risks; cost–benefit analysis and cost-effectiveness; mapping; future policies; and further research. This assessment of the state of radon research is focused on the UK as an example of a country where radon has been on the governmental agenda since the late 1970s, but also highlights radon issues throughout the world in, for example, the USA, Europe and Asia.

Abstract Radon is generally regarded as a naturally occurring radiological hazard but we report here measurements of significant, hazardous radon concentrations that arise from man-made sources: for example, radium-dial watches. This study is an examination and assessment of health risks from radium and uranium found in historical artefacts, and the radon that emanates from them. This includes radium-dial watches, the main focus, plus clocks, aircraft instruments, and ornaments and artefacts made of uranium glass/uranium-glazed. Such objects were very popular in the 1930s and 1940s, and are still readily available today. A collection of 30 radium-dial pocket and wrist watches was measured and shown to be capable of giving rise to radon concentrations two orders of magnitude greater than the UK Domestic Action Level of 200 Bq m −3 in unventilated or poorly ventilated rooms. Furthermore, individual watches are capable of giving rise to radon concentrations in excess of the UK Domestic Action Level. We also highlight a gap in remediation protocols, which are focused on preventing radon entering buildings from outside, with regard to internally generated radon hazards. Radon as arising from man-made objects, such as radium-dial watches, should be considered appropriately in radon protocols and guidelines.

Abstract In 2014, the Geological Survey of Austria (GBA) published – in cooperation with further national institutions – an overview map on radionuclides in groundwater, rocks and stream sediments at a scale of 1:500 000 with explanatory notes. In the frame of this activity, the uranium, 228 Ra, 226 Ra, 222 Rn, 210 Pb and 210 Po analyses in groundwater studies made by the Austrian Agency for Health and Food Safety (AGES) and Environment Agency of Austria (Umweltbundesamt), as well as the uranium and thorium analyses of stream sediments of the GBA and whole-rock analyses from different sources, were evaluated statistically. Furthermore, the GBA’s comprehensive airborne radiometric data were exploited. The aim of this study was to work out typical spectra of the radionuclide content in the groundwater and aquifers of different geological settings. It appeared that the concentration of 222 Rn in groundwater depends significantly on the uranium content of the aquifer. In contrast to this, the other radionuclides in groundwater did not show a clear correlation with uranium and thorium in the subsurface geology. Concerning 228 Ra, 226 Ra, 210 Pb and 210 Po, the lack of relationship to the subsurface composition seems to be a result of the low concentrations in groundwater. With respect to uranium in groundwater, there is a mixed situation: on the one hand, high uranium concentrations in groundwater can be observed in the Alps in regions with uranium bearing orthogneisses. On the other hand, in sediment basins of NE Austria where the underlying geology contains little uranium. Whether this is caused by special geological features combined with the given low precipitation or by the extensive agriculture (uranium from phosphate fertilizer) is under examination. Concerning the threshold values of the radionuclides in groundwater (radiation), no exceedance could be observed. In spite of this, the concentration of the heavy metal uranium sometimes exceeded the threshold value of 15 µg l −1 : this is especially true for the regions mentioned above. In addition, an attempt was made to compare the Austrian values with data from neighbouring countries. It became clear that only a few published datasets exist that are comparable. Radon analyses of soil gas in the Czech Republic and Bavaria show the same geological patterns as the Austrian radon analyses of the groundwater. In addition, to enable the reader to compare the Austrian data with datasets from other countries, additional tables are included here for all types of data. They show the statistic distributions of different geological classes in a coordinated way. Supplementary material: An Austrian map and explanation notes showing the uranium content of the underground and radionuclides in ground water are available at https://doi.org/10.6084/m9.figshare.c.3780170

Abstract Effective radium-226 concentration, EC Ra , is the product of radium activity concentration, C Ra , multiplied by the emanation coefficient, E , which is probability of producing a radon-222 atom in the pore spaces. It is measured by accumulation experiments in the laboratory, achieved routinely for a sample mass >50 g using scintillation flasks to measure the radon concentration. We report on 3370 EC Ra values obtained from more than 11 800 such experiments. Rocks ( n =1351) have a mean EC Ra value of 1.9±0.1 Bq kg −1 (90% of data in the range 0.11–35 Bq kg −1 ), while soils ( n =1524) have a mean EC Ra value of 7.5±0.2 Bq kg −1 (90% of data between 1.4 and 28 Bq kg −1 ). Using this large dataset, we establish that the spatial structure of EC Ra is meaningful in geology or sedimentology. For plants ( n =85), EC Ra is generally <1 Bq kg −1 , but values of larger than 10 Bq kg −1 are also observed. Dedicated experiments were performed to measure emanation, E , in plants, and we obtained values of 0.86±0.04 compared with 0.24±0.04 for sands, which leads to estimates of the radium-226 soil-to-plant transfer ratio. For most measured animal bones ( n =26), EC Ra is >1 Bq kg −1 . Therefore, EC Ra appears essential for radon modelling, health hazard assessment and also in evaluating the transfer of radium-226 to the biosphere.

Abstract A total of 2143 dissolved radon-222 and radium-226 activity concentrations measured together in water samples was compiled from the literature. To date, the use of such a large database is the first attempt to establish a relationship for the 226 Ra– 222 Rn couple. Over the whole dataset, radon and radium concentrations range over more than nine and six orders of magnitude, respectively. Geometric means yield 9.82±0.73 Bq l −1 for radon and 54.6±2.7 mBq l −1 for radium. Only a few waters are in 226 Ra– 222 Rn radioactive equilibrium, with most of them being far from equilibrium; the geometric mean of the radium concentration in water/radon concentration in water ( C Ra / C Rn ) ratio is estimated to be 0.0056±0.0004. Significant differences in radon and radium concentrations are observed between groundwaters and surface waters, on the one hand, and between hot springs and cold springs, on the other. Within water types, typical ranges of radon and radium concentrations can be associated with subgroups of waters. While the radium concentration characterizes the geochemistry of the groundwater–rock interaction, the radon concentration, in most cases, is a signal of non-mobile radium embedded in the encasing rocks. Thus, the 226 Ra– 222 Rn couple can be a useful tool for the characterization of water and for the identification of water source rocks, shedding light on the various water–rock interaction processes taking place in the environment. Supplementary material: The database is available as a table at https://doi.org/10.6084/m9.figshare.c.3582131