Discussion on framework of radon management strategy in various environments

Activities on radon management strategy of international organisations (International Atomic Energy Agency, International Commission on Radiation Protection, etc.) should be carefully and continuously traced to discuss how to control radon in various environments, for example, dwellings, workplace, underground, caves, mines, hot springs, disposal facilities and so on. It is more reasonable in parallel to set radon reference level by effective dose criteria of Sv y(-1) as well as by radon concentration in air of Bq m(-3). How to investigate radon concentration in each environment, and how to make decisions on needed action for radiation protection from natural radon,--these should be discussed for each environmental situation on a case-by-case basis. International discussion as well as domestic discussion is continuously needed, not only among the radon specialists and regulators, but also including stakeholders who are the main users of regulation and guidance.     

21st century challenges in radiation protection and shielding: draft 2005 recommendations of ICRP

The International Commission on Radiological Protection regularly examines the status of its recommendations and reviews the increasing knowledge of the effects of exposure to ionising radiation in order to decide whether new recommendations are needed. The Commission strives to make its system more coherent and comprehensible, while recognising the need for stability in international and national regulations, many of which have, only fairly recently, implemented the 1990 Recommendations. However, new scientific data have been produced since 1990 and there have been societal developments in that more openness or transparency is expected in developing new recommendations and, in addition, there has been a move from the utilitarian approach of 'the greatest good for the greatest number', to one with more concern for the 'individual', all of which have inevitably led to some changes in the formulation of the recommendations. This paper outlines the proposals for the 2005 Recommendations.     

Finnish radon situation analysed using national measurement database

Radiation and Nuclear Safety Authority (STUK) maintains the national indoor radon measurement database in Finland. The analysis of the database material supplements information on radon situation collected by random sampling surveys. The 92,000 dwellings in the database are not a representative sample of the Finnish housing stock. However, the bias is compensated by calculating radon parameters in 1-km(2) cells and weighting the cells by the number of dwellings in the cell. Both the database material and a recent random sampling survey show that radon concentrations in new Finnish houses have been decreasing since the 1990s. This positive trend is clearly stronger in radon-prone areas where preventive measures are nowadays commonly implemented in new construction. The changeover to mechanical supply and exhaust ventilation together with the increase in crawl-space foundations has also contributed to the decrease in the concentrations.     

History of the measurement of radon in central Bohemia

It is a little surprising, but radon has been measured by our Institute for >50 y. In the first phase this was carried out in underground mines (up to the present day) but more and more attention has been paid to domestic dwellings and NORM workplaces. The number of the measurements (grab sampling underground, SSNTDs application) was relatively high. To the routine work of the Institute is added research and calibration for radon measuring organisations. Since the formation of the Czech Republic, our previous institution was reformed by the State Office for Nuclear Safety and is one of the two organisations whose main task is, among others, radon measurement.     

Indoor radon measurements in the granodiorite area of Bergama (Pergamon)-Kozak, Turkey

Indoor radon levels in 20 dwellings of rural areas at the Kozak-Bergama (Pergamon) granodiorite area in Turkey were measured by the alpha track etch integrated method. These dwellings were monitored for eight successive months. Results show that the radon levels varied widely in the area ranging from 11±1 to 727±11 Bq m(-3) and the geometric mean was found to be 63 Bq m(-3) with a geometric standard deviation of 2 Bq m(-3). A log-normal distribution of the radon concentration was obtained for the studied area. Estimated annual effective doses due to the indoor radon ranged from 0.27 to 18.34 mSv y(-1) with a mean value of 1.95 mSv y(-1), which is lower than the effective dose values 3-10 mSv given as the range of action levels recommended by International Commission on Radiation Protection. All dosimetric calculations were performed based on the guidance of the UNSCEAR 2000 report.     

Radon programme: presence and future

An overview of radon programme experience is presented. The paper summarises broad topics concerning radon issue: philosophy of radon policy, radon measurements strategies with respect to indoor radon variation, progress in radon measurement of an individual house (radon diagnosis), national programmes, the role of preventive measures and interventions with respect to existing and future exposure and knowledge of radon risk, problems of remediation strategies, radon mapping process and sense of delineation of radon prone areas, public awareness on radon issue and publicity campaign. Some research activities are proposed aiming at effective solutions for radon issues in the future.     

Radon in workplaces: first results of an extensive survey and comparison with radon in homes

Extensive radon surveys have been carried out in many countries only in dwellings, whereas surveys in workplaces are rather sparse and generally restricted to specific workplaces/activities, e.g. schools, spas and caves. Moreover, radon-prone areas are generally defined on the basis of radon surveys in dwellings, while radon regulations use this concept to introduce specific requirements in workplaces in such areas. This approach does not take into account that work activities and workplace characteristics can significantly affect radon concentration. Therefore, an extensive survey on radon in different workplaces have been carried out in a large region of Italy (Tuscany), in order to evaluate radon distribution in workplaces over the whole territory and to identify activities and workplace characteristics affecting radon concentration. The results of this extensive survey are compared with the results of the survey carried out in dwellings in the same period. The workplaces monitored were randomly selected among the main work activities in the region, including both public and industrial buildings. The survey monitored over 3500 rooms in more than 1200 buildings for two consecutive periods of ～6 months. Radon concentration was measured by means of passive nuclear track detectors.     

Radon measurements by nuclear track detectors in dwellings in Oke-Ogun area, South-Western, Nigeria

An indoor radon survey of a total of 77 dwellings randomly selected in 10 districts in Oke-Ogun area of Oyo state, South-western Nigeria was carried out using CR-39 detectors. The CR-39 detectors were placed in the bedrooms and living rooms and exposed for 6 months and then etched in NaOH 6.25 N solution at 90 °C for 3 h. Mean concentrations amount to 255 ± 47 and 259 ± 67 Bq m(-3) in the living rooms and bedrooms, respectively. The lowest radon concentration (77 ± 29 Bq m(-3)) was found in Igbeti, whereas the highest was found in Okeho (627 ± 125 Bq m(-3)). The annual exposure of dwellers was estimated to fall <10 mSv (6.4 and 6.5 mSv y(-1) n living rooms and bedrooms, respectively), which is the upper range of action levels recommended by the International Commission on Radiological Protection. The average excess lung cancer risk was estimated 24.8 and 25.2 per million person-years in both living rooms and bedrooms. It is believed that the high radon level in this part of the country may be attributed to its geographic location. The data presented here will serve as a baseline survey for radon concentration in dwellings in the area.     

Indoor radon concentration in the rural dwellings of Chhattisgarh state (India)

Inhalation of radon and its daughter products is the major contributor to the total exposure of the population to natural radiation. An indoor radon survey has been carried out in the state of Chhattisgarh (80.26 degrees N to 84.41 degrees N and 17.8 degrees E to 24.1 degrees E), India under the national coordinated radon project of the Department of Atomic Energy. In the frame of this project indoor radon concentration has been measured in 105 dwellings situated in different villages of Chhattisgarh state. Houses were selected for measurements to cover the most common type of houses generally existing in the rural areas. Measurements have been done on quarterly integrating cycle for one full year in each dwelling using radon cup dosemeter employing LR-115, type-II (pelliculable), solid-state nuclear track detectors. The gamma radiation level was also checked in each dwelling using a gamma survey meter. It was found that the annual average indoor radon concentration in these dwellings varies from 9.91 to 87.84 Bq m(-3) with overall mean value of 26.48 Bq m(-3). Gamma level in these rural dwellings varies from 14.84 to 26.56 microR h(-1) with mean value of 18.68 microR h(-1). We observed that the radon concentration is relatively higher in the houses where the floor is bare but relatively lower in those houses where the floor is tiled or cemented.     

Indoor radon concentration and its possible dependence on ventilation rate and flooring type

The results of radon concentration measurements carried out in dwellings with natural ventilation for 1 y in Bangalore are reported. Measurements, covering three sessions of the day (morning, afternoon, night) were performed two times in a month for 1 y at a fixed place of each dwelling at a height of 1 m above the ground surface in selected dwellings. The low-level radon detection system (LLRDS), an active method, was used for the estimation of radon concentration. The measurements were aimed to understand the diurnal variation and the effect of ventilation rate and flooring type on indoor radon concentration. The geometric mean (± geometric standard deviation) of indoor radon concentration from about 500 measurements carried out in 20 dwellings is found to be 25.4 ± 1.54 Bq m?3. The morning, afternoon and night averages were found to be 42.6 ± 2.05, 15.3 ± 2.18 and 28.5 ± 2.2 Bq m?3, respectively. The approximate natural ventilation rates of the dwellings were calculated using the PHPAIDA--the on-line natural ventilation, mixed mode and air infiltration rate calculation algorithm and their effects on indoor radon concentrations were studied. The inhalation dose and the lung cancer risk due to indoor radon exposure were found to be 0.66 mSv y?1 and 11.9 per 10? persons, respectively. The gamma exposure rate was also measured in all the dwellings and its correlation with the inhalation dose rate was studied.     

On the assessment of the performance of personal dosemeters and individual monitoring services

Based on recommendations of the International Commission on Radiological Protection, recommendations and requirements on the performance of dosimetric systems and individual monitoring services have been formulated in national and international standards and other documents of relevance. Although these all have essentially the same aim, the formulated criteria and the guidance given vary. Using the individual monitoring service of NRG in Arnhem and its thermoluminescence dosemeter as an example, the current paper reviews a number of ways to estimate the uncertainty in dose assessments and compares the criteria given in recommendations and standards. An attempt is made to contribute to some convergence of recommendations and requirements on aspects of dosimetric performance.     

Ethical issues related to professional exposure of pregnant women in the medical field: monitoring and limiting effective dose

The International Commission on Radiological Protection recommendations for occupational exposed pregnant women do not imply necessarily the complete avoidance of work with radiation or radioactive materials. Instead, a careful review of the exposure conditions, once the pregnancy is declared, as part of the exercise of the ICRP optimisation principle (based in a teleological ethics point of view) is suggested. The dose limitation (following a deontological ethics point of view) of the fetus/embryo is, however, not clearly well established as happens in the case of workers or members of the public. Also, the justification of practices (to continue to work or not with radiation or radioactive materials) is not clearly addressed in most national or international recommendations. An analysis of this justification (bearing in mind both teleological and deontological ethics) is examined in this work having in mind the best interest of the child-to-be as well as other existing social and economical factors.     

Quarantine,cholera, and international health spaces: Reflections on 19th-century European sanitary regulations in the time of SARS-CoV-2

The current SARS-CoV-2 crisis raises questions about the challenges faced by nation states and international organisations in offering a coordinated international response to the pandemic, and reveals the great vulnerability of European countries, which are implementing lockdown measures and imposing restrictions on international travel, for the most part on a unilateral basis. Such measures run counter to the prevailing approach of the previous two centuries that developed an international public health space. This article examines the measures adopted by European states in order to contain 19th-century cholera pandemics, which took shape through the development of an international maritime quarantine system, based primarily on the implementation of national regulations and local decision-making. This regime was quickly viewed as ineffective and out of step with liberal ideas that urged a “laissez-faire” approach to public health matters. In its stead, a long-term trend developed towards easing quarantine measures. Nation states supported the internationalisation of the fight against pandemics, which chiefly consisted of externalising quarantine measures to the East in order to eliminate them in Europe. This process was based on a subtle dialectical relationship between the construction of an international public health space and the affirmation of state sovereignty, and continued into the 20th century with the progressive creation of international institutions responsible for advancing global health.     

Regional variations pattern of indoor radon levels in some areas of Punjab and Haryana

The indoor radon concentration levels and their regional variationspattern, for two consecutive half-year periods, in a wide rangeof dwellings of some regions of Punjab and Haryana states havebeen studied. The objective was to find the relation betweenthe variations of indoor radon levels with the sub-soil andlocal geology, type of building materials utilised in the dwellingsof the region. Keeping this in view, indoor radon measurementshave been carried out in the dwellings of 30 villages aroundthe Tusham Ring Complex, Bhiwani district, Haryana, known tobe composed of acidic volcanics and associated granites, alongwith 11 villages of Amritsar District, Punjab. The indoor radonconcentration in the dwellings around Tusham (Haryana) was foundto vary from 120 ± 95 to 915 ± 233 Bq m^–3,whereas radon levels varied from 60 ± 37 to 235 ±96 Bq m^–3 for the dwellings studied in Punjab. We believethat local geology including embedded granitic rocks, and sub-soil,as well as building materials having higher radioactive content,is the major contributor for the higher indoor radon levelsobserved particularly in the dwelling around Tusham Ring complex,where some dwellings are showing higher radon concentrationsthan the ICRP recommendations. The environmental samples fromsome areas of Punjab state and around the Tusham Ring Complexof Haryana state have also been analysed for radon exhalationstudies. Higher values for radon exhalation rates have beenobserved for the Tusham's soil/rock specimens, as compared withsoil samples of the Amritsar region of Punjab.     

Quality assurance and quality control programme in the Personal Dosimetry Department of the Greek Atomic Energy Commission

A quality assurance (QA) and quality control (QC) programme was applied to the personal monitoring department (TLD based) of the Greek Atomic Energy Commission (GAEC). This programme was designed according to the recommendations of international bodies such as the International Organization for Standardization (ISO), the International Electrotechnical Commission (IEC), the International Atomic Energy Agency (IAEA) and the European Commission (CEC). This paper deals with the presentation of the QA/QC programme which includes administrative data and information, technical checking of the equipment, acceptance tests of new equipment and dosemeters, issuing and processing of the dosemeters, dose evaluation, record keeping and reporting, traceability and reproducibility, handling of complaints, internal reviews and external audits.     

Exposure data and risk indicators for safety performance assessment in Europe

The objective of this paper is the analysis of the state-of-the-art in risk indicators and exposure data for safety performance assessment in Europe, in terms of data availability, collection methodologies and use. More specifically, the concepts of exposure and risk are explored, as well as the theoretical properties of various exposure measures used in road safety research (e.g. vehicle- and person-kilometres of travel, vehicle fleet, road length, driver population, time spent in traffic, etc.). Moreover, the existing methods for collecting disaggregate exposure data for risk estimates at national level are presented and assessed, including survey methods (e.g. travel surveys, traffic counts) and databases (e.g. national registers). A detailed analysis of the availability and quality of existing risk exposure data is also carried out. More specifically, the results of a questionnaire survey in the European countries are presented, with detailed information on exposure measures available, their possible disaggregations (i.e. variables and values), their conformity to standard definitions and the characteristics of their national collection methods. Finally, the potential of international risk comparisons is investigated, mainly through the International Data Files with exposure data (e.g. Eurostat, IRTAD, ECMT, UNECE, IRF, etc.). The results of this review confirm that comparing risk rates at international level may be a complex task, as the availability and quality of exposure estimates in European countries varies significantly. The lack of a common framework for the collection and exploitation of exposure data limits significantly the comparability of the national data. On the other hand, the International Data Files containing exposure data provide useful statistics and estimates in a systematic way and are currently the only sources allowing international comparisons of road safety performance under certain conditions.     

Evidence of children's vulnerability to radiation in the context of radiological/nuclear events and considerations for emergency response

International organisations, such as International Atomic Energy Agency, United Nations Scientific Committee on the Effects of Atomic Radiation and World Health Organisation, together with committees of experts such as Biological Effects of Ionising Radiation and Committee on Medical Aspects of Radiation in the Environment, have assessed the effects of radiation on large exposed populations (Chernobyl accident, and Hiroshima/Nagasaki atomic bombings) and on nuclear energy workers and people living near nuclear facilities. Childhood and in utero exposure to moderate and high levels of ionizing radiation, such as those experienced during the atomic bombings of Japan, or from radiotherapy, is an established cause of leukaemia and solid cancer. There is no evidence of increase in solid cancers (excluding thyroid cancer) or leukaemia in the children from Chernobyl, and no evident link between worker's exposure to radiation and leukaemia in their offspring or with the presence of leukaemia clusters around nuclear power plants. It has also not been possible to demonstrate the evidence of radiation hereditary effects in human populations. In accordance with international guidance, Canadian Nuclear Safety Commission recommends optimisation of protection strategies to reduce doses to children. The development of credible radiological/nuclear event scenarios would assist in identifying probable sources of radioactivity and pathways of exposure for children. Such scenarios should then be used to identify protection strategies appropriate for children.     

Recent developments in radon metrology: new aspects in the calibration of radon, thoron and progeny devices

Due to the importance of reliable measurements of radon activity concentration, one of the past developments in metrology was applied to the field of radon, thus meeting two basic needs: (1) the harmonisation of metrology within the scope of the mutual recognition arrangement, an arrangement drawn up by the International Committee of Weights and Measures for the mutual recognition of national standards and of calibrations issued by national metrology institutes and (2) the increased demands of the European Atomic Energy Community (EURATOM) directive, transferred into national radiation protection regulations with regard to natural radioactivity and its quality-assured measurements. This paper gives an overview of typical technical procedures in the radon-measuring technique group of PTB, covering all aspects of reference atmospheres (primary standards) for radon, thoron and their respective progenies.     

Dosimetric and epidemiological approaches to assessing radon doses--can the differences be reconciled?

A significant problem in internal radiation dosimetry is the discrepancy between the radiation dose from exposure to radon inferred from epidemiological studies and the higher dose calculated using the Human Respiratory Tract Model (HRTM) adopted by the International Commission on Radiological Protection (ICRP). The difference is a factor of about 3. The agreement between these two assessments by radically different approaches is surprisingly good. Nevertheless, there has been concern to understand fully the reasons for this discrepancy and to attempt to reconcile the two approaches. This is of importance because radon contributes about half of the total effective dose from natural background radiation. Furthermore, the HRTM was developed with application to radon exposure in mind, yet at present it is not used for risk assessment purposes although ICRP does suggest that it is useful for comparative dosimetry.     

Radon hazard and risk in Sussex, England and the factors affecting radon levels in dwellings in chalk terrain

A survey was undertaken of radon levels in 1013 dwellings in Sussex, UK. A number of dwellings were identified with high radon levels in an area previously considered to offer low radon risk from geological sources. Multiple regression was used to determine the relative influence of the various geographical and building-related factors on indoor radon levels. The radon hazard, independent of building-related effects, was determined for each surveyed location by standardising radon measurements to a 'model' dwelling. These were entered into a geographic information system and related to surface geology. The highest radon levels were found to be associated with the youngest Chalk formations, Tertiary deposits and Clay-with-flints Quaternary deposits in the area. Radon potentials were also determined for the area which can be used to estimate radon risk and assist in environmental planning and development control.