National Radon Action Plans in Europe and Need of Effectiveness Indicators: An Overview of HERCA Activities.

Protection of the population and of workers from exposure to radon is a unique challenge in radiation protection. Many coordinated actions and a variety of expertise are needed. Initially, a National Radon Action Plan (NRAP) has been developed and implemented by some countries, while it is currently recommended by international organizations (e.g., World Health Organization) and required by international regulations, such as the European Council Directive 2013/59/Euratom and the International Basic Safety Standards on Radiation Protection and Safety of Radiation Sources, cosponsored by eight international organizations. Within this framework, the Heads of the European Radiological Protection Competent Authorities (HERCA) have organized activities aimed at sharing experiences to contribute toward the development and implementation of effective NRAPs. Two workshops were held in 2014 and 2015, the latter on radon in workplaces. As a follow-up to these, an online event took place in March 2021, and a second specific workshop on NRAP is planned for June 2022. These workshops were attended by experts from the competent authorities of European countries, relevant national and international organizations. The experience of several countries and the outcomes from these workshops have highlighted the need for adequate indicators of the effectiveness and progress of the actions of NRAPs, which could also be useful to implement the principle of optimization and the graded approach in NRAPs. In this paper, the activities of HERCA to support the development and implementation of effective NRAPs are described and some examples of effectiveness indicators are reported, including those already included in the NRAP of some European countries.

Lung cancer mortality attributable to residential radon exposure in Spain and its regions.

Lung cancer has the highest cancer mortality rate in developed countries. The principal risk factor for lung cancer is tobacco use, with residential radon being the leading risk factor among never smokers and the second among ever smokers. We sought to estimate mortality attributable to residential radon exposure in Spain and its Autonomous Regions, with correction for dwelling height and differentiation by tobacco use. We applied a prevalence-based method for estimating attributable mortality. For estimations, we considered exposure to radon in the different Autonomous Regions corrected for dwelling height, using the National Statistics Institute Housing Census and prevalence of tobacco use (never smokers, smokers and ex-smokers). The results showed that 3.8% (838 deaths) of lung cancer mortality was attributable to radon exposure of over 100 Bq/m3, a figure that rises to 6.9% (1,533 deaths) when correction for dwelling height is not performed. By Autonomous Region, the highest population attributable fractions, corrected for dwelling height, were obtained for Galicia, Extremadura, and the Canary Islands, where 7.0, 6.9, and 5.5% of lung cancer mortality was respectively attributable to radon exposure. The greatest part of the attributable mortality occurred in men and among smokers and ex-smokers. Residential radon exposure is a major contributor to lung cancer mortality, though this contribution is highly variable among the different territories, indicating the need for targeted prevention policies. Correction of estimates for dwelling height is fundamental for providing reliable estimates of radon-attributable mortality.

Geolocation of premises subject to radon risk: Methodological proposal and case study in Madrid.

Useful information on the potential radon risk in existing buildings can be obtained by combining data from sources such as potential risk maps, the 'Sistema de Información sobre Ocupación del Suelo de España' (SIOSE) [information system on land occupancy in Spain], cadastral data on built property and population surveys. The present study proposes a method for identifying urban land, premises and individuals potentially subject to radon risk. The procedure draws from geographic information systems (GIS) pooled at the municipal scale and data on buildings possibly affected. The method quantifies the magnitude of the problem in the form of indicators on the buildings, number of premises and gross floor area that may be affected in each risk category. The findings are classified by type of use: residential, educational or office. That information may guide health/prevention policies by targeting areas to be measured based on risk category, or protection policies geared to the construction industry by estimating the number of buildings in need of treatment or remediation. Application of the methodology to Greater Madrid showed that 47% of the municipalities have houses located in high radon risk areas. Using cadastral data to zoom in on those at highest risk yielded information on the floor area of the vulnerable (basement, ground and first storey) premises, which could then be compared to the total. In small towns, the area affected differed only scantly from the total, given the substantial proportion of low-rise buildings in such municipalities.

210Po and major ions in drainage water from soil treated with various types of fertilizers.

The levels of (210)Po, nutrients (NH(4)(+), NO(3)(-), PO(4)(3 -)) and major ions (Na(+), K(+), Mg(2 +), Ca(2 +), F(-), NO(2 -), Br(-), Cl(-), SO(4)(2 -)) were determined, by means of lysimeter experiences, in drainage waters for agricultural soils untreated and treated with different types of fertilizers (animal manure, sewage sludge and NPK synthetic fertilizer) applied at several rates. Analytical determinations were performed by using alpha -spectrometry in the case of (210)Po, or Ion Exchange liquid chromatography for the other ionic species. Statistical uni and multivariate analysis of the results shown significant differences among lixiviates according to the different fertilizer treatments. Sewage sludge and manure applications resulted in similar compositions of lixiviates with low (210)Po levels, whereas synthetic fertilizers produced higher (210)Po concentrations and different concentration patterns of ionic species when applied at or above the recommended rates. All (210)Po levels were well below the limits proposed by the 2001/928/ Euratom Recommendation. The concentrations of the rest of the ionic species, exception made from NH(4)(+) and NO(3)(-), were also below the limits proposed by Spanish regulations.

Regional calibration of erosion radiotracers (210Pb and 137Cs): atmospheric fluxes to soils (northern Spain).

Inventories of radionuclides commonly used to study environmental processes, especially in erosion research, were determined in soil cores from two distant river basins in northern Spain. Results showed that 210Pb atmospheric fluxes correlate very well with mean annual rainfall across the region, and this is also the case for 137Cs inventories but only on the basin scale. Therefore we suggest that 210Pb is a better candidate as a radiotracer for soil erosion studies. In this region, the equation 210Pb flux (Bq m(-2) yr(-1)) = (0.19 +/- 0.02) x rainfall (mm yr(-1)) - (24 +/- 17) can be used as a calibration to estimate input 210Pb fluxes, a key parameter in soil erosion studies and models, when mean annual rainfall is known.