EVALUATION OF DOSE IN SLEEP BY MATTRESS CONTAINING MONAZITE.

Some companies in Korea have sold beds which contain a processed product containing monazite powder. Consumers may receive external exposure by radiation emitted by progeny radionuclides in uranium and thorium, and internal exposure through the breathing of radon progeny radionuclides produced in the decay chain. Thus, in this study, age specific dose conversion factors (mSv y-1 Bq-1) by external exposure and dose conversion factors by internal exposure (mSv y-1 per Bq m-3) were derived. Besides, a dose assessment program were developed to calculate dose by taking into account real conditions. And the age specific dose was evaluated using the radioactive concentration measured by the NSSC. As a results, external exposure was assessed to get effective doses in the range of 0.00086 to 0.0015 mSv y-1 by external exposure and a committed effective doses in the range of 1.3 to 12.26 mSv y-1 by internal exposure for all age groups.

BRONCHUS AND LUNG CANCER INCIDENCE IN POPULATION LIVING AROUND THE FORMER URANIUM MAINING AND MILING SITES.

The indoor radon concentrations and lung cancer incidence in Eleshnitza village and Blagoevgrad district of Bulgaria were examined in the study reported here. The Eleshnitza was the second largest uranium mining and milling region of the country. The geometric mean of indoor radon concentration in Eleshnitza (465 Bq/m3) was higher than the geometric mean of Blagoevgrad district (78 Bq/m3). Retrospective analyses on lung cancer incidence, covering the period 1995-2012 have been shown the same trend. The results were suggestive of an existing relationship between the two variables. Possible effects attributable to age and gender on lung cancer incidence were examined and found to be significant.

[Ecological-hygienic evaluation of the environment of territories being adjacent to decultivated uranium mines].

On the territory of Kazakhstan there are uranium deposits, many ofwhich are in mothballed since times of perestroika. Often, the mines are flooded and represent a "time-delay bomb". Inside of mines various there are accumulated gases of both organic and inorganic nature, periodically thrown out and adversely affecting on the health of local populations. The aim of the study was the investigation of the state of the environment of Esilsky district of the Akmola region by common pollutants and chemicals. As the basic variable for the investigation of ambient air there was accepted the maximum one-time concentration of suspended substances, phenol, nitrogen dioxide, sulfur dioxide. The results were evaluated in relation to the MPC for the analyzed substance in the air according to maximal single MPC (MPCms) and daily average MPC (MPCda). The content of metals in the water was determined with the use of spectrophotometer PD-303S. Evaluation of the results was executed in relation of the MPC of substances in water, by means of the comparison with the requirements of Federal standards for drinking water, samples from drinking water sources. There were executed calculations of the overall index of water pollution (IWVgen), the index of water pollution by heavy metals (IWVhm). Chemical analysis of soil was carried out with the use of spectrophotometer PD- 303S (Japan), the photometer expert-003 "Ekoniks". Evaluation of the results was carried out with the respect to the MPC in the soil, the toxicity of all components. Summarizing soil pollution index was evaluated for metals contained in the soil at the level of more than or equal to 1 MAC. The settlement Krasnogorskiy and the village of Kalachi were found to be characterized by a low level of air pollution, increased rigidity of drinking water exceeded the maximum permissible concentrations of copper by 3.45 times and chloride by 1.17 times in the soil cover.

Calculation of lifetime lung cancer risks associated with radon exposure, based on various models and exposure scenarios.

The risk of lung cancer mortality up to 75 years of age due to radon exposure has been estimated for both male and female continuing, ex- and never-smokers, based on various radon risk models and exposure scenarios. We used risk models derived from (i) the BEIR VI analysis of cohorts of radon-exposed miners, (ii) cohort and nested case-control analyses of a European cohort of uranium miners and (iii) the joint analysis of European residential radon case-control studies. Estimates of the lifetime lung cancer risk due to radon varied between these models by just over a factor of 2 and risk estimates based on models from analyses of European uranium miners exposed at comparatively low rates and of people exposed to radon in homes were broadly compatible. For a given smoking category, there was not much difference in lifetime lung cancer risk between males and females. The estimated lifetime risk of radon-induced lung cancer for exposure to a concentration of 200 Bq m(-3) was in the range 2.98-6.55% for male continuing smokers and 0.19-0.42% for male never-smokers, depending on the model used and assuming a multiplicative relationship for the joint effect of radon and smoking. Stopping smoking at age 50 years decreases the lifetime risk due to radon by around a half relative to continuing smoking, but the risk for ex-smokers remains about a factor of 5-7 higher than that for never-smokers. Under a sub-multiplicative model for the joint effect of radon and smoking, the lifetime risk of radon-induced lung cancer was still estimated to be substantially higher for continuing smokers than for never smokers. Radon mitigation-used to reduce radon concentrations at homes-can also have a substantial impact on lung cancer risk, even for persons in their 50 s; for each of continuing smokers, ex-smokers and never-smokers, radon mitigation at age 50 would lower the lifetime risk of radon-induced lung cancer by about one-third. To maximise risk reductions, smokers in high-radon homes should both stop smoking and remediate their homes.

Lung cancer risk due to residential radon exposures: estimation and prevention.

Epidemiological studies proved that cumulative exposure to radon is the second leading cause of lung cancer, the world's most common cancer. The objectives of the present study are (i) to analyse lung cancer risk for chronic, low radon exposures based on the transformation frequency-tissue response (TF-TR) model formulated in terms of alpha particle hits in cell nuclei; (ii) to assess the percentage of attributable lung cancers in six areas of Transylvania where the radon concentration was measured and (iii) to point out the most efficient remediation measures tested on a pilot house in Stei, Romania. Simulations performed with the TF-TR model exhibit a linear dose-effect relationship for chronic, residential radon exposures. The fraction of lung cancer cases attributed to radon ranged from 9 to 28% for the investigated areas. Model predictions may represent a useful tool to complement epidemiological studies on lung cancer risk and to establish reasonable radiation protection regulations for human safety.

Statistical analysis of observational study of the influence of radon and other risk factors on lung cancer incidence.

An observational study is a type of epidemiological study when the researcher observes the situation but is not able to change the conditions of the experiment. The statistical analysis of the observational study of the population of Lermontov city (North Caucasus) was conducted. In the initial group, there were 121 people with lung cancer diagnosis and 196 people of the control group. Statistical analysis was performed only for men (95 cases and 76 controls). The use of logistic regression with correction on age gives the value of odds ratio 1.95 (0.87÷4.37; 90% CI) per 100 working levels per month of combined (occupational and domestic) radon exposure. It was demonstrated that chronic lung diseases are an additional risk factor for uranium miners but it is not a significant risk factor for general population. Thus, the possibility of obtaining statistically reliable results in the observational studies when using the correct methods of analysis is demonstrated.

Natural radioactivity in drinking underground waters in Upper Silesia and solid wastes produced during treatment.

Content of (226)Ra, (228)Ra and uranium isotopes in waters from subsurface aquifers was studied. The sampling points were chosen for having the elevated natural content of iron and manganese. Measurements of radium were made by LSC, while uranium was measured by alpha spectrometry. Waste sludge was measured by gamma spectrometry and three-stage BCR sequential extraction was performed. Radon activity concentration in the air at water treatment plants was determined and dose adsorbed by staff was calculated.

Assessment of indoor absorbed gamma dose rate from natural radionuclides in concrete by the method of build-up factors.

The specific absorbed gamma dose rates, originating from natural radionuclides in concrete, were calculated at different positions of a detection point inside the standard room, as well as inside an example room. The specific absorbed dose rates corresponding to a wall with arbitrary dimensions and thickness were also evaluated, and appropriate fitting functions were developed, enabling dose rate calculation for most realistic rooms. In order to make calculation simpler, the expressions fitting the exposure build-up factors for whole (238)U and (232)Th radionuclide series and (40)K were derived in this work, as well as the specific absorbed dose rates from a point source in concrete. Calculated values of the specific absorbed dose rates at the centre point of the standard room for (238)U, (232)Th and (40)K are in the ranges of previously obtained data.

Lung cancer risk from occupational and environmental radon and role of smoking in two Czech nested case-control studies.

The aim of the present study was to evaluate the risk of lung cancer from combined exposure to radon and smoking. Methodologically, it is based on case-control studies nested within two Czech cohort studies of nearly 11,000 miners followed-up for mortality in 1952-2010 and nearly 12,000 inhabitants exposed to high levels of radon in homes, with mortality follow-up in 1960-2010. In addition to recorded radon exposure, these studies use information on smoking collected from the subjects or their relatives. A total of 1,029 and 370 cases with smoking information have been observed in the occupational and environmental (residential) studies, respectively. Three or four control subjects have been individually matched to cases according to sex, year of birth, and age. The combined effect from radon and smoking is analyzed in terms of geometric mixture models of which the additive and multiplicative models are special cases. The resulting models are relatively close to the additive interaction (mixing parameter 0.2 and 0.3 in the occupational and residential studies, respectively). The impact of the resulting model in the residential radon study is illustrated by estimates of lifetime risk in hypothetical populations of smokers and non-smokers. In comparison to the multiplicative risk model, the lifetime risk from the best geometric mixture model is considerably higher, particularly in the non-smoking population.

Interaction of radon and smoking among Czech uranium miners.

The study is based on a case-control study nested within a cohort study (11 000 miners and 1074 lung cancers). The controls were individually matched by year of birth and attained age. Smoking data were collected in person or from relatives of deceased subjects or from medical files. The study resulted in 850 cases of lung cancer with smoking data. The linear dependence of lung cancer relative risk (RR) on radon exposure adjusted for smoking was not substantially different from analyses when smoking was ignored and reflected mainly the risk among smokers. However, the excess RR per unit exposure among never smokers (70 cases) was substantially higher in comparison with that in smokers, reflecting differences in lung morphometry and clearance. The RRs from combined effects are substantially lower than the risk derived from the multiplicative model, but somewhat higher than those from the additive model. The work was supported by the Czech Ministry of Health (IGA NS 10596).

[Case-control study of lung cancer and combined home and work radon exposure in the town of Lermontov].

Relation between the risk of lung cancer and combined home and work indoor radon exposure was studied on the example of the population of Lermontov town (Stavropol Region, Russia). The town is situated in the former uranium mining area. Case (121 lung cancer cases) and control (196 individuals free of lung cancer diagnosis) groups of the study included both ex-miners and individuals that were not involved in the uranium industry. Home and work radon exposures were estimated using archive data as well as contemporary indoor measurements. The results of our study support the conclusion about the effect of radon exposure on the lung cancer morbidity.

Accounting for smoking in the radon-related lung cancer risk among German uranium miners: results of a nested case-control study.

The possible confounding effect of smoking on radon-associated risk for lung cancer mortality was investigated in a case-control study nested in the cohort of German uranium miners. The study included 704 miners who died of lung cancer and 1,398 controls matched individually for birth year and attained age. Smoking status was reconstructed from questionnaires and records from the mining company's health archives for 421 cases and 620 controls. Data on radon exposure were taken from a job-exposure matrix. Smoking adjusted odds ratios for lung cancer in relation to cumulative radon exposure have been calculated with conditional logistic regression. The increase in risk per Working Level Month (WLM) was assessed with a linear excess relative risk (ERR) model taking smoking into account as a multiplicative factor. In addition, the potential impact of temporal factors on the ERR per WLM was examined. Lung cancer mortality risk increased with increasing radon exposure, yielding a crude ERR per WLM of 0.25% (95% CI: 0.13-0.46%). Adjustment for smoking led only to marginal changes of the radon-associated lung cancer risks. The adjusted ERR per WLM was very similar (0.23%, 95%-CI: 0.11-0.46%) to the crude risk and to the risk found in the Wismut cohort study. This stability of the radon-related lung cancer risks with and without adjustment for smoking suggests that smoking does not act as a major confounder in this study and presumably also not in the cohort study.

Escaping radioactivity from coal-fired power plants (CPPs) due to coal burning and the associated hazards: a review.

Coal, like most materials found in nature, contains trace quantities of the naturally occurring primordial radionuclides, i.e. of (40)K and of (238)U, (232)Th and their decay products. Therefore, the combustion of coal results in the released into the environment of some natural radioactivity (1.48 TBq y(-1)), the major part of which (99%) escapes as very fine particles, while the rest in fly ash. The activity concentrations of natural radionuclides measured in coals originated from coal mines in Greece varied from 117 to 435 Bq kg(-1) for (238)U, from 44 to 255 Bq kg(-1) for (226)Ra, from 59 to 205 Bq kg(-1) for (210)Pb, from 9 to 41 Bq kg(-1) for (228)Ra ((232)Th) and from 59 to 227 Bq kg(-1) for (40)K. Fly ash escapes from the stacks of coal-fired power plants in a percentage of 3-1% of the total fly ash, in the better case. The natural radionuclide concentrations measured in fly ash produced and retained or escaped from coal-fired power plants in Greece varied from 263 to 950 Bq kg(-1) for (238)U, from 142 to 605 Bq kg(-1) for (226)Ra, from 133 to 428 Bq kg(-1) for (210)Pb, from 27 to 68 Bq kg(-1) for (228)Ra ((232)Th) and from 204 to 382 Bq kg(-1) for (40)K. About 5% of the total ash produced in the coal-fired power plants is used as substitute of cement in concrete for the construction of dwellings, and may affect indoor radiation doses from external irradiation and the inhalation of radon decay products (internal irradiation) is the most significant. The resulting normalized collective effective doses were 6 and 0.5man-Sv(GWa)(-1) for typical old and modern coal-fired power plants, respectively.

Bioaccumulation and behavioural effects of depleted uranium in rats exposed to repeated inhalations.

Depleted uranium has numerous industrial and military uses. Contamination by inhalation of airborne compounds is probably the most important route of exposure. In humans, there are no data clearly demonstrating neurotoxicity of uranium, yet some experimental studies suggest a link between neurological toxicity and uranium exposure. In this work, the bioaccumulation of uranium in male rats after exposure to repeated depleted uranium dioxide inhalation (30 min inhalation at 197 mgm(-3), 4 days a week for 3 weeks) has been studied, together with the behavioural effects. The uranium concentrations in the brain 1 day after the end of the exposure period varied as follows: olfactory bulb>hippocampus>frontal cortex>cerebellum, subsequently decreasing rapidly. The spontaneous locomotion activity of exposed rats was increased 1 day post exposure and the spatial working memory was less efficient 6 days post exposure, compared with control rats. These data suggest that depleted uranium is able to enter the brain after exposure to repeated inhalation, producing behavioural changes.

[Uranium exposure and cancer risk: a review of epidemiological studies]. / Exposition à l'uranium et risque de cancer: une revue des études épidémiologiques.

OBJECTIVE: At the end of 2000, certain diseases including leukemia were reported among soldiers who participated in the Balkan and in the Gulf wars. Depleted uranium used during these conflicts was considered as a possible cause. Its radiotoxicity is close to that of natural uranium. This paper reviews the epidemiological knowledge of uranium, the means of exposure and the associated risk of cancer. METHODS: The only available epidemiological data concerns nuclear workers exposed to uranium. A review of the international literature is proposed by distinguishing between uranium miners and other workers of the nuclear industry. French studies are described in details. RESULTS: In ionizing radiation epidemiology, contamination by uranium is often cited as a risk factor, but the dose-effect relationship is rarely studied. Retrospective assessment of individual exposure is generally insufficient. Moreover, it is difficult to distinguish between uranium radiotoxicity, its chemical toxicity and the radiotoxicity of its progeny. A causal relation between lung cancer and radon exposure, a gas derived from the decay of uranium, has been demonstrated in epidemiological studies of miners. Among other nuclear workers exposed to uranium, there is a mortality deficit from all causes (healthy worker effect). No cancer site appears systematically in excess compared to the national population; very few studies describe a dose-response relationship. CONCLUSION: Only studies with a precise reconstruction of doses and sufficient numbers of workers will allow a better assessment of risks associated with uranium exposure at levels encountered in industry or during conflicts using depleted uranium weapons.

Analysis of radon-induced lung cancer risk by a stochastic state-vector model of radiation carcinogenesis.

A biologically based state-vector model (SVM) of radiation carcinogenesis has been extended to incorporate stochasticity of cellular transitions and specific in vivo irradiation conditions in the lungs. Dose-rate-dependent cellular transitions related to the formation of double-stranded DNA breaks, repair of breaks, interactions (translocations) between breaks, fixation of breaks, cellular inactivation, stimulated mitosis and promotion through loss of intercellular communication are simulated by Monte Carlo methods. The stochastic SVM has been applied to the analysis of lung cancer incidence in uranium miners exposed to alpha-emitting radon progeny. When incorporating in vivo features of cell differentiation, stimulated cell division and heterogeneity of cellular doses into the model, excellent agreement between epidemiological data and modelling results could be obtained. At low doses, the model predicts a nonlinear dose-response relationship; e.g., computed lung cancerrisk at 20WLM is about half of current lung cancer estimates based on the linear hypothesis. The model also predicts a slight dose rate effect; e.g., at a cumulative exposure of 20 WLM, calculated lung cancer incidence for an exposure rate 0.27 WLM/year (assuming an exposure time of 73 years) is smaller by a factor of 1.2 than that for an exposure rate of 10 WLM/year.

Lung cancer risk in the French cohort of uranium miners.

The French cohortof uranium miners includes 5098 miners,and 125 lung cancer deaths have been observed. The relationship between radon exposure and risk of lung cancer is estimated using relative risk models, which allow investigation of time dependent modifying factors such as the period of exposure, time since exposure and exposure rate. A linear exposure-response relationship is observed. The main modifier is the period of exposure before or after 1956: the excess relative risk after introduction of ventilation in the French mines is eight times higher than before. The decrease in risk with time since exposure and exposure rate disappears when period of exposure is taken into account. Compared to most of the uranium miner studies, this cohort constitutes a population exposed to low levels and low rates of radon for a long duration. The extension of the French cohort leads to an important increase in its statistical power. Exposure rate effect will be further investigated, in the framework of a European collaborative research project aiming at the synthesis of the effects of radon exposure at low dose and low dose rate.

Czech miner studies of lung cancer risk from radon.

Epidemiological evidence of lung cancer risk from radon is based mainly on studies of miners. Two such studies among Czech uranium miners were established in 1970 and 1980. A subcohort of 5002 miners and a nested-in case-control study contribute to a joint European project. In this paper, the subcohort of miners with 495 lung cancers is described. The excess relative risk depends linearly on cumulative exposure incurred more than 5 years before. The relative effect from exposures in the distant past decreases by 62% per decade. Simultaneously, the excess relative risk is lower by 43% per decade in dependence on age at exposure. The effect of smoking, partly analysed in the study, suggests a twofold elevation in the relative risk coefficient among non-smokers, but this difference is not significant.