Well water radioactivity and risk of cancers of the urinary organs

Water from bedrock frequently contains higher concentrations of natural radionuclides than water from other sources. Bladder and kidneys receive a radiation dose when radioactive isotopes are excreted into urine. The subjects for this case-cohort study were selected from all drilled wells users in Finland. The study comprised 61 bladder cancer and 51 kidney cancer cases diagnosed between 1981 and 1995, as well as a random sample of 274 reference persons, stratified by age and sex. The median activity concentrations of radon in drilled wells used by bladder and kidney cancer cases and the reference cohort were 170, 140, and 130 Bq/L, respectively. The radium concentration was 0.01 Bq/L for all groups and the uranium concentrations were 0.08, 0.07, and 0.06 Bq/L, respectively. The bladder cancer risks associated with radon, radium, and uranium activity concentrations in drinking water were 1.02 (0.68-1.54) per log(100 Bq of radon/L), 0.73 (0.21-2.50) per log(0.1 Bq of radium/L), and 0.77 (0.32-1.89) per log(1 Bq of uranium/L). The corresponding figures for kidney cancer were 0.81 (0.47-1.37), 0.12 (0.01-1.10), and 0.92 (0.36-2.35), respectively. In conclusion, even though ingested radionuclides from drilled wells are a source of radiation exposure, they are not associated with a substantially increased risk of bladder or kidney cancers in concentrations occurring in drilled wells.     

Indoor radon and well water radon in Virginia and Maryland

The domestic use of radioactive water has long been a cause for concern, but only a few studies have examined prolonged exposure to radionuclide concentrations found in natural settings. This paper reports on the indoor radon concentrations from 1,500 homes in northern Virginia and southern Maryland and well water radon from 700 homes in the same area. Indoor radon concentrations are almost all between 1 and about 40 pCi/L. The winter season shows the highest values with about 40% of the homes over the US EPA action level of 4.0 pCi/L. The summer season shows the lowest values with about 25% of the homes over this level. This seasonal variation is related to home ventilation. Waterborne radon in homes with private well ranges from about 100 pCi/L to about 8,000 pCi/L. In small homes, indoor radon can be significantly increased by outgassing of the home water supply, even at water radon levels of less than 10,000 pCi/L.     

Indoor radon exposure and lung cancer risk: a review of case-control studies

BACKGROUND: Radon is a radioactive gas that tends to accumulate in indoor environment. A causal relationship between lung cancer and radon exposure has been demonstrated in epidemiologic studies of miners. The objective of this paper is to present the results of case-control studies of lung cancer risk associated with indoor radon exposure. METHODS: Case-control studies published since 1990 are included in this review. This type of protocol is particularly well suited for studying the relationship between indoor radon exposure and lung cancer risk, taking into account possible confounding factors such as tobacco smoking. The characteristics and results of these studies are summarized. The limitations associated with each of these studies are also discussed. RESULTS: The results of available studies are relatively concordant and suggest a positive association between lung cancer risk and indoor radon exposure with an estimated excess relative risk of about 6 to 9% per 100Bq/m3 increase in the observed time-weighted average radon concentration. The order of magnitude of this estimation agrees with extrapolations from miners but some studies may suffer from inadequate statistical power. CONCLUSION: At present, efforts are underway to pool together the data from the existing studies of indoor radon. This pooling analysis with thousands of cases and controls will provide a more precise estimate of the lung cancer risk from indoor radon exposure and explore the effect of modifying factors, such as smoking.     

Controls on radioactivity in water supplies in England and Wales, with especial reference to radon.

This note describes the legal and administrative controls on concentrations of radioactive materials, with especial reference to radon, in drinking water in England and Wales. These controls follow the EC Drinking Water Directive and Recommendations from the European Union. The Directive relates to radioactivity in drinking water generally, while the Recommendations are specific to radon. A distinction is made between private and public supplies, with more stringent controls on the latter. In general, problems in meeting the recommended levels are not expected in England and Wales.     

Dosimetry of radon progeny deposited on skin in air and thermal water

It is held that the skin dose from radon progeny is not negligibly small and that introducing cancer is a possible consequence under normal circumstances as there are a number of uncertainties in terms of related parameters such as activity concentrations in air and water, target cells in skin, skin covering materials, and deposition velocities. An interesting proposal has emerged in that skin exposure to natural radon-rich thermal water as part of balneotherapy can produce an immune response to induce beneficial health effects. The goal of this study was to obtain generic dose coefficients with a focus on the radon progeny deposited on the skin in air or water in relation to risk or treatment assessments. We thus first estimated the skin deposition velocities of radon progeny in air and thermal water based on data from the latest human studies. Skin dosimetry was then performed under different assumptions regarding alpha-emitting source position and target cell (i.e. basal cells or Langerhans cells). Furthermore, the impact of the radon progeny deposition on effective doses from all exposure pathways relating to ‘radon exposure’ was assessed using various possible scenarios. It was found that in both exposure media, effective doses from radon progeny inhalation are one to four orders of magnitude higher than those from the other pathways. In addition, absorbed doses on the skin can be the highest among all pathways when the radon activity concentrations in water are two or more orders of magnitude higher than those in air.     

Radon-222 in the gastrointestinal tract: a proposed modification of the ICRP Publication 30 model

The New England states have a long involved history of radon in individual well water supplies. As a result of these previous findings on the abundance of radon, coupled with its potential health impact, the New England Radiological Health Committee (NERHC) formulated a technical working group in 1980 which was charged with evaluating the possibility of developing uniform concentration guidelines for radon in individual domestic water supplies. This working group determined that the current ICRP Publication 30 metabolic model for the gastrointestinal (GI) tract was inadequate to address the empirically observed rates of 222Rn removal from the body. A modification to the ICRP Publication 30 GI tract model is proposed which attempts to resolve these differences. Calculations are presented, using both the original and modified ICRP Publication 30 models, which indicate that individual potable water supplies containing 222Rn concentrations as high as 400,000 pCi/l. do not significantly increase the probability of stomach or intestinal cancer, as defined by the BEIR III risk estimates. Since this paper deals exclusively with the GI tract, no attempt is made to address the lung burden imposed by the contribution of radon released into the household air by aeration at the tap or other fixtures. Only when the contribution of the radon water source term to both the respiratory and ingestion pathways is evaluated as a whole can any meaningful standard for 222Rn in individual domestic water supplies be established.     

太原市居民室内氡水平抽样调查与所致剂量估算

目的了解室内空气中氡的本底水平,找出氡的不同来源对室内的相对贡献。方法 REM-2型氡析出率仪对地面和墙壁表面进行氡析出的测量,利用FD-125氡钍分析仪对室内用水和煤气中氡的含量作了分析,探讨了太原市居室内空气中氡本底水平。结果室内氡主要是由土壤、建材中析出的,其次才是室外空气中氡的渗入,室内用水和煤气中氡贡献很小。结论根据调查结果,进行室内空气中氡对人体健康危害分析和剂量评价,建立了室内氡本底水平的数据库,为以后研究室内氡的防护措施提供了依据。     

Indoor radon pollution in houses in the Apulian Region of Italy and evaluation of the probability of lung cancer in the population

BACKGROUND: Radon-222 is a gaseous radioactive chemical which can be transformed into other radioactive chemicals, defined as "products of decay" or "radon's daughter". The modality of radon penetration into the buildings depends on the convection motion created in the ground, which suck it back, so causing the penetration. The principal effect on human health is the increase risk of lung cancer, in proportion to the concentration and the time people spend indoors with exposure to radon. OBJECTIVES: The study proposed to estimate the expected cases of radon-induced lung cancer in the population of Apulia due to contamination by indoor radon. METHODS: The study used the data obtained in a national survey made by ANPA (National Environmental Protection Agency) and ISS (High Health Institute), with the collaboration of the Regional Reference Centres for the Control of Environmental Radioactivity (CRR). In the Apulia Region 310 families (5000 nationwide) were involved, which were selected so as to constitute a representative sample both of the region and the country. Appropriate instruments for the measurement of mean concentrations of indoor radon (passive nuclear trace monitors were installed in the homes of the sample families in two different periods of year). We evaluated the variations of indoor radon concentration in the houses during spring-summer and autumn-winter periods, observing a predictable increase in the latter period. We assessed concentrations in relation to: 1. architectural features and location, 2. construction year, 3. building material, 4. presence of windows. RESULTS: We found higher contamination in the oldest non-cement buildings and on the lower floors. In Lecce and Castrì di Lecce we found a mean radon concentration higher than the national and the regional mean, which is equivalent to annual exposure of 0.54 and 0.46 WLM respectively. For these levels we estimated that the expected cases of radon-induced lung cancer will be 1.5 in Lecce and 1.3 in Castrì per 10,000 inhabitants. CONCLUSION: The results of our investigations confirm that indoor radon pollution is a significant problem as it is one of the main causes of lung cancer. Hence, precautionary measures to reduce as much as possible exposure to indoor radon are highly recommended.     

地热水的利用及其对人体健康的影响

我国地热水中氟化物含量比较高(1.37～17.5mg/L)。地热点周围的地面水、土壤和农作物均受到不同程度的氟污染。健康影响调查表明,地热点儿童氟斑牙患病率尚未见有螬长趋势,但是远期影响不能忽视。经常接触地热水的儿童的唾液溶菌酶含量有所增加。长期接触地热水的工作人员的皮肤刺痒和脱发现象增多,白细胞计数低于对照组,这可能与地热水中含有大量的盐类、硫化氢和放射性氡有关系。     

The development of the UK radon programme.

The natural radioactive gas, radon, is responsible for the largest component of the radiation dose received by the average UK citizen. The risks of exposure to radon have been demonstrated and quantified in epidemiological studies of those exposed at work and in the home. In the UK, measures are in place to identify and help control the exposures in those houses where levels are highest, to limit levels in new buildings and to control exposures in the workplace. This paper outlines the development of the programme, with special reference to the identification and remediation of homes with high radon levels.     

北京市生活饮用水放射性水平调查分析

目的调查北京市生活饮用水的放射性水平,以更好地开展本地区饮用水放射卫生监测与评价。方法抽查北京市9个区县55个生活饮用水水样,包括井水29个、自来水21个和地面水5个,使用BH1217B双路弱α、β测量仪测量水中的总α和总β放射性,使用RTM2200连续氡测量仪测量水中放射性氡浓度。结果 55个水样中总α浓度最高值为0.325 Bq/L,总β浓度最高值为0.331 Bq/L,均低于我国《生活饮用水卫生标准》GB 5749—2006规定的指导值;地表水氡浓度均值仅为0.62 Bq/L,远低于地下井水中氡浓度的均值(15.95 Bq/L),地下水源井水中氡浓度和总α无直接关系。结论生活饮用水中放射性水平受多种因素影响,应进行持续监测以及时发现和控制水中的意外污染。     

Radon and lung cancer risk: an extension of the mortality follow-up of the Newfoundland fluorspar cohort

Radon is a well-recognized cause of lung cancer, and studies of underground miners have provided invaluable insights on the mechanisms of radon carcinogenesis. Given the dramatic decreases in occupational exposures and the latent interval between the time of exposure and the development of lung cancer, continued follow-up of these cohorts is needed to address uncertainties in risk estimates. Here, we report on the relationship between radon and lung cancer mortality in a cohort of 1,742 Newfoundland fluorspar miners between 1950 and 2001; follow-up has been extended 11 y from previous analyses. The standardized mortality ratio (SMR) was used to compare the mortality experience of the cohort to similarly aged Newfoundland males. Poisson regression methods were used to characterize the radon-lung cancer relationship with respect to: age at first exposure, attained age, time since last exposure, interactions with cigarette smoking, and exposure rate. In total, 191 lung cancers were observed among underground miners (SMR = 3.09; 95% CI = 2.66, 3.56). ERR/WLMs decreased with attained age and time since last exposure. An inverse dose-rate effect was observed, while age at first exposure was not associated with lung cancer risk. An important strength of this study is that the effects of gamma radiation, thoron, and radioactive dust, common exposures in other miner studies, can be ruled out because the source of radon was from water running through the mine. However, the results should be interpreted cautiously due to uncertainties associated with the estimation of radon exposure levels before ventilation was introduced into the mine, and the relatively small number of lung cancer deaths that precluded joint modeling of multiple risk factors.     

Endocrine disrupting compounds (EDCs) and pharmaceuticals and personal care products (PPCPs) in the aquatic environment: implications for the drinking water industry and global environmental health

Endocrine disrupting compounds (EDCs) and pharmaceuticals and personal care products (PPCPs) are a group of chemical compounds with diverse physical and chemical properties. Recent studies have indicated undesired effects of EDCs and PPCPs at their reported trace concentrations (ng l^-1 to mg l^-1). This paper reviews the current knowledge on the sources, properties, occurrence and health impacts of EDCs and PPCPs, and their removal from drinking water using ozonation and ozone/hydrogen peroxide-based advanced oxidation. The paper also examines the potential threats posed by these chemicals to drinking water and public health. While these compounds are known to have adverse effects on ecosystem health, notably in the fish population, a similar link is yet to be established between ingestion of these compounds through drinking water and human health. In addition, data on the effectiveness of existing methods for the removal of these compounds are not conclusive. Further studies are required to characterize risks, and also to evaluate and optimize existing removal processes. Also concerted international effort is urgent to cut down the risk of exposure and restrain the production and marketing of toxic chemicals.     

贵州省某磷矿区氡气及放射性水平的评价

目的 研究和评价贵州省某磷矿区磷矿氡气及放射性水平。方法 通过现场检测和实验室分析对磷矿区周围辐射水平、氡气、矿石和土壤核素分析、水的总放射性水平分析。结果 磷矿区的γ外照射为7~18(×10^-8 Gy/h),平均值为12×10^-8Gy/h;氡浓度水平为105~246Bq/m³;矿石²²⁶Ra放射性核素水平为156.7~372.3Bq/kg,平均值为222.6Bq/kg;矿井水总放射性水平最大为总α为0.175Bq/L、总β为0.374Bq/L,饮用水总放射性水平最大为总α为0.0327Bq/L、总β为0.174Bq/L。结论 磷矿放射性水平符合国家相关标准的要求;矿井水和饮用水的总放射性水平相关无显著性意义;井下氡气浓度未达到干预水平。     

The precautionary principle applied to lung cancer risk caused by residential radon

Residential radon seems to represent a major health hazard. The studies, which investigate the pulmonary risk of cancer caused by radon, are of different nature and their results are divergent. Thus, there persist scientific uncertainties concerning the real size of this risk. The application of the precautionary principle is based on an analysis of these uncertainties. Studies on miners, studies concerning residential radon (at individual and ecological level), as well as experimental data allow for the organisation of the uncertainty of each one of these specific approaches taking into account their proper limitations. The first risk that is linked to radon is the risk of pulmonary cancer. Miner occupational exposure studies appear compatible with the results of case-control studies concerning residential radon. However, the case-control studies, where the risk appears more present, are contradicted by ecological studies, often not very convincing about the existence of a risk. The case-control studies have an intrinsic advantage over the ecological studies because they limit the classification errors by the individualization of the relation-exposure effect. In addition, the experimental data are not in contradiction with the existence of effects for very small exposures. Consequently, the inherent scientific uncertainties of the totality of these data, can be classified and permit the application of the precautionary principle in a better proportioned way. The utilisation of the precautionary principle implies the necessity to limit, as far as possible, the exposure to residential radon. Precautionary principle is based on the debated hypothesis of no threshold linear relation between radon exposition and health consequences. This relation has been established on professional and residential exposures. The implementation of this epidemiological model shows the "residential radon" risk as the second cause of pulmonary cancer and responsible of about 10% of these specific cancers.     

Radon in public water supplies in Migdonia basin, Central Macedonia, Northern Greece

The main objective of this work is the accurate measurement of radon concentration in the public water supplies of the Migdonia basin in Northern Greece. The main aim is to localize the sub-areas that present high radon concentrations in water and to inform the local authorities so that more detailed studies might be set up in these areas. About 80 samples from special bore holes and taps that supply the local population with fresh water were collected in order to obtain detailed radon measurements. For the analyses, a liquid scintillation counting system, using the Packard protocol for measuring radon in water, was employed. The results of the investigation show that radon concentrations in these public water supplies are significant. The concentrations ranged from background concentrations to 170 Bq x L(-1). The level of 50 Bq x L(-1) is exceeded in 23% of water supplies. These preliminary results with initial data interpretation and inter-comparison assessment are presented. These results of the analyses showed that elevated radon concentrations were detected in water samples from an area at the western part of the Lake Volvi, due probably to the local intense tectonism, and from a village above the Lake Koronia.     

Assessment of radiation dose from radon ingestion and inhalation in commercially bottled drinking water and its annual effective dose in Eastern Province,Saudi Arabia

The isotopes of radium, uranium, polonium, lead, and short-lived radon are the common radionuclides found in drinking water. The abnormal amount of radon in drinking water causes health risks. In this study, an attempt has been made to estimate the level of radon concentrations and its annual effective dose from bottled water brands and tap drinking water. A total of 77 samples of drinking water sources; 47 bottled water brands and 27 tap water samples including 3 samples from water storage tank supplier were collected and examined. The measurements were performed using active detection method technique called Durridge RAD7-H₂O with closed loop. The minimum and maximum level of average radon concentrations was 0.10 ± 0.02 BqL^?1 and 9.2 ± 0.02 BqL^?1. The results were below the limit recommended by the Environmental Protection Agency (11 BqL^?1). The annual effective dose for children and adults was in the range from almost 0.51 µSvy^?1 to 46.69 µSvy^?1. There are no indications of significant threat from radon concentrations in bottled water brands or tap drinking water, and it is safe as far as health hazard is concerned.     

Should radon be reduced in homes? A cost-effect analysis

BACKGROUND: Radon is a radioactive gas that may leak into buildings from the ground. Radon exposure is a risk factor for lung cancer. An intervention against radon exposure in homes may consist of locating homes with high radon exposure (above 200 Bq m(-3)) and improving these, and protecting future houses. The purpose of this paper is to calculate the costs and the effects of this intervention. METHODS: We performed a cost-effect analysis from the perspective of the society, followed by an uncertainty and sensitivity analysis. The distribution of radon levels in Norwegian homes is lognormal with mean = 74.5 Bq m(-3), and 7.6% above 200 Bq m(-3). RESULTS: The preventable attributable fraction of radon on lung cancer was 3.8% (95% uncertainty interval: 0.6%, 8.3%). In cumulative present values the intervention would cost $238 (145, 310) million and save 892 (133, 1981) lives; each life saved costs $0.27 (0.09, 0.9) million. The cost-effect ratio was sensitive to the radon risk, the radon exposure distribution, and the latency period of lung cancer. Together these three parameters explained 90% of the variation in the cost-effect ratio. CONCLUSIONS: The uncertainty in the estimated cost per life is large, mainly due to uncertainty in the risk of lung cancer from radon. Based on estimates from road construction, the Norwegian society has been willing to pay $1 million to save a life. This is above the upper uncertainty limit of the cost per life. The intervention against radon in homes, therefore, seems justifiable.     

Radon concentration measurements and personnel exposure levels in Bavarian water supply facilities

As part of a study covering the whole of Bavaria, the southern most of Germany's 16 states, water supply facilities were examined to determine the radon (222Rn) concentrations in ground water and indoor air and the radon exposure to the staff working in these buildings. Bavaria can be divided into ten geological regions of different geogenic radon potential. From each region, a number of water supply facilities proportional to the size of the region were selected for measurements. Over 500 of a total number of 2,600 water supply facilities were asked to take a 1-L groundwater sample and expose several track-etch detectors in order to obtain the mean room concentration of the main staff work places. In addition, for a period of 2 mo, the personnel had to wear a track-etch detector during the time they spent in the supply facilities. The resulting measurements were then used to estimate their individual effective dose of radon and its progenies. In the East Bavarian crystalline region, the region of the highest geogenic radon potential within Bavaria, indoor radon gas concentrations of up to 400 kBq m(-3) were observed. About 10% of the process controllers in this region are subjected to an annual effective dose of more than 20 mSv. In the other Bavarian regions, only 2% of staff exposure levels exceed this limit. The correlation between the radon concentration measurements of the indoor air, the ground water, and individual personnel exposure levels was determined. The average ratio of the radon indoor air to the processed groundwater concentration is 0.14. But due to the different types of ventilation in the various supply facilities, there can be great variations in this figure. Therefore, there is no clear relationship between the groundwater and the indoor air concentration of a supply facility. This study also reveals no clear relationship between radon indoor air concentrations and the personnel exposure levels of a supply facility.     

Population attributable fraction for lung cancer due to residential radon in Switzerland and Germany

Studies on miners as well as epidemiological studies in the general population show an increased lung cancer risk after exposure to radon and its progeny. The European pooled analysis of indoor radon studies estimates an excess relative risk of 8% (16% after correction for measurement uncertainties) per 100 Bq m(-3) indoor radon concentration. Here, we determine the population attributable fraction (PAF) for lung cancer due to residential radon based on this risk estimate for Switzerland and Germany. Based on regionally stratified radon data, the PAF was calculated following the World Health Organization concept of global burden of disease, compared to a realistic baseline radon concentration equal to the outdoor concentration. Lifetable approaches were used taking smoking and sex into account. Measurement error corrections were applied to both risk estimates and the radon distribution. In Switzerland, the average indoor radon concentration is 78 Bq m(-3), resulting in a PAF of 8.3%. Therefore, 169 male lung cancer deaths and 62 deaths in women can be attributed to residential radon per year. For Germany, the average indoor radon concentration is 49 Bq m(-3), corresponding to a PAF of 5.0% (1,422 male and 474 female deaths annually). In both countries, a large regional variation in the PAF was observed due to regional differences in radon concentrations and population structure. Both calculations show a strong dependency on the risk model used. Risk models based on miner studies result in higher PAF estimates than risk models based on indoor radon studies due to different assumptions regarding exposures received more than 35 years ago. The use of a non-zero baseline radon concentration also contributes to the lower PAF estimates reported here. Although the estimates of the population attributable fraction of residential radon presented here are lower than previously reported estimates, the risk is still one of the most widespread environmental hazards. Radon monitoring and radon reduction programs are therefore important issues for environmental public health management.