Residential radon and lung cancer: a cohort study in Galicia, Spain / Radón residencial y cáncer de pulmón: un estudio de cohorte en Galicia, España / Radônio residencial e câncer de pulmão: um estudo de coorte na Galícia, Espanha

Case-control studies show an association between residential radon and lung cancer. The aim of this paper is to investigate this association through a cohort study. We designed an ambispective cohort study using the Galician radon map, Spain, with controls drawn from a previous case-control study. Subjects were recruited between 2002 and 2009. The data were cross-checked to ascertain lung cancer incidence and then analysed using a Cox regression model. A total of 2,127 subjects participated; 24 lung cancer cases were identified; 76.6% of subjects were drawn from the radon map. The adjusted hazard ratio was 1.2 (95%CI: 0.5-2.8) for the category of subjects exposed to 50Bq/m3 or more. This risk rose when subjects from the case-control study were analyzed separately. In conclusion, we did not observe any statistically significant association between residential radon exposure and lung cancer; however, it appears that with a sample of greater median age (such as participants from the case-control study), the risk of lung cancer would have been higher.

Los estudios de casos y controles muestran una asociación entre el radón residencial y el cáncer de pulmón. El objetivo del artículo fue investigar esa asociación a través de un estudio de cohorte. Proyectamos un estudio de cohorte ambispectivo, utilizando el mapa de radón de Galicia, España, con los controles obtenidos de un estudio anterior de casos y controles. Los individuos fueron reclutados entre 2002 y 2009. Los datos fueron verificados para confirmar la incidencia de cáncer de pulmón y después analizados con un modelo de regresión de Cox. Participaron un total de 2.127 individuos; se identificaron 24 casos de cáncer de pulmón; un 76,6% de los individuos fueron obtenidos a través del mapa de radón. El hazard ratio ajustado era 1,2 (IC95%: 0,5-2,8) para la categoría de individuos expuestos a 50Bq/m3 o más. El riesgo aumentó cuando los individuos del estudio de casos y controles fueron analizados separadamente. En conclusión, no se observó una asociación estadísticamente significativa entre exposición al radón residencial y cáncer de pulmón; sin embargo, parece que con una muestra con una media de edad más elevada (tales como los participantes del estudio de casos y controles), el riesgo de cáncer de pulmón habría sido más alto.

Estudos de casos e controles mostram uma associação entre radônio residencial e câncer de pulmão. O artigo teve como objetivo investigar essa associação através de um estudo de coorte. Projetamos um estudo ambispectivo coorte, utilizando o mapa de radônio da Galícia, Espanha, com os controles obtidos de um estudo anterior de casos e controles. Os indivíduos foram recrutados entre 2002 e 2009. Os dados foram verificados para confirmar a incidência de câncer de pulmão e depois analisados com um modelo de regressão de Cox. Participaram um total de 2.127 indivíduos; foram identificados 24 casos de câncer de pulmão; 76,6% dos indivíduos foram obtidos através do mapa de radônio. O hazard ratio ajustado era 1,2 (IC95%: 0,5-2,8) para a categoria de indivíduos expostos a 50Bq/m3 ou mais. O risco aumentou quando os indivíduos do estudo de casos e controles foram analisados separadamente. Em conclusão, não foi observada associação estatisticamente significativa entre exposição ao radônio residencial e câncer de pulmão; entretanto, parece que com uma amostra com mediana de idade mais elevada (tais como os participantes do estudo de casos e controles), o risco de câncer de pulmão teria sido mais alto.

[Evaluation of the natural gamma radiation level in residential zones and determination of annual effective exposure dose in the residents of Hamadan province, Iran, 2012]

Human is always exposed to natural background ionizing radiation which may have harmful effects; therefore, measurement of the natural background radiation is important. In this study, was measured the dose of effective natural background gamma radiation in indoor residential zones of Hamadan Province. In this cross-sectional study, we selected four stations along the main geographic directions and one in the center of city for measurement of the indoor dose rate in each of the cities in Hamadan Province. Based on the household numbers, some houses were selected randomly in every station and natural background indoor dose was measured by using RDS-110 survey meter. Then, using the results of our previous study about measuring the level of outdoor natural gamma radiation in this province, we determined the level of annual effective exposure dose from natural gamma radiation in Hamadan residents. In Hamadan province cities, maximum and minimum indoor natural background radiation [gamma ray] belonged to Razan City [1.41 +/- 0.079 mSv] and Asadabad City [0.955 +/- 0.044 mSv], respectively. Mean annual equivalent indoor dose in Hamadan Province was 1.20 +/- 0.070 mSv. Also the maximum indoor natural background radiation dose [gamma ray] in the buildings with the age of more and less than 25 years were 1.42 +/- 0.219 mSv and 1.44 +/- 0.149 mSv, respectively. According to the results of this study and our previous study about outdoor gamma natural background radiation, the annual effective dose in Hamadan Province residents was 0.83 mSv. According to the results of this study, it seems that annual effective equivalent dose due to indoor gamma radiation in Hamadan Province exceeded the mean external exposure amount reported by UNSCEAR [0.5 mSv]. Also the annual effective dose due to gamma background radiation in Hamadan Province residents is 0.83 mSv, which is higher than the global average [0.48 mSv] reported by UNSCEAR - 2000. Therefore epidemiological studies to assess the prevalence of chronic diseases associated with natural radiation exposure among Hamadan Province residents are recommended

Indoor radon survey in Shiraz-Iran using developed passive measurement method

While in the open air the amount of radon gas is very small and does not pose a health risk, in confined spaces, radon can accumulate to relatively high levels and become a health hazard. Exposure to high levels of radon has been associated with an increased risk of lung cancer, depending on the time length of exposure. Radon level in dwelling of Shiraz with 1,200,000 populations has been sampled and analyzed in this study. Our study could be considered the largest radon study in Iran both time and area wise. In this study, radon [222Rn] concentration in residential dwellings in Shiraz-Iran was sampled and measured during two consecutive six month periods in 2009-2010. We used Solid State Nuclear Track Detectors [SSNTD], CR-39 polycarbonate films. The survey parameters of radon concentrations were floor types, construction materials and dwelling's age. Annual average indoor radon concentration for the survey period was 94 +/- 52 Bq/m3. The calculated mean annual effective doses in basements and different floors were less than the lowest limit recommended action level of 3 mSv by ICRP. High radon concentrations are measured in basements and old dwellings; however, due to rapidly changing housing structures and ventilation practices with no intervention, lower levels of radon concentration has been expected in Shiraz

Radium and Radon exhalation studies of soil

Everyone is exposed to radon because it is present everywhere with varying concentrations. Radon and its progeny are well established as lung carcinogenic. Track etch technique using LR-115 plastic track detectors has been used to measure the effective radium content and radon exhalation rates in soil samples collected from urban area of Etah district of Uttar Pradesh province in Northern India. The values of effective radium content are found to vary from 27.87 to 45.14 Bq.kg-[1] with a mean value of 34.98 Bq.kg-[1]. The mass exhalation rates of radon vary from 2.38 _ 10[-6] to 3.86 _ 10[-6] Bq.kg[-1].d[-1] with a mean value of 2.99 _ 10-6 Bq.kg[-1].d[-1]. The surface exhalation rates of radon have been found to vary from 6.19 _ 10[-5] to 10.03 _ 10[-5] Bq.m [-2].d[-1] with a mean value of 7.77 _ 10[-5] Bq.m [-2].d[-1]. Radon exhalation study is important for understanding the relative contribution of the material to the total radon concentration found inside the dwellings. The values of radium and radon exhalation rates are found to be below the safe limit recommended by OECD, 1979

Radioactivity and radiation hazard assessment of Cauvery River, Tamilnadu, India

Natural radiation is constantly present in the environment and is emitted from a variety of natural and artificial sources. It affects human body and environment. The activity concentrations of [238]U, [232]Th and [40]K have been determined by Gamma ray spectrometer with an HPGe detector in sediments of Cauvery River, Tamilnadu, India. The absorbed dose rate, radium equivalent concentration, external [Hex] and internal [Hin] hazardous indices are calculated from criteria formula and compared with the international recommended limits. The radioactive heat production rate and activity concentration index are also calculated. The observed dose rate measurements from ERDM [Environmental Radiation Dosi Meter] at 1m above the ground level at each site of the both rivers are measured and correlated with calculated absorbed dose rate. From the various parameters and correlation between them, the Cauvery River does not pose a radiological hazard except the site no. 21, 22, 23, 30, 31 and 35

[Effective dose rate of radon gas in Jooshan hot spring of Kerman Province]

Human beings are constantly exposed to different radiations that have always been recognized as a health hazard. Radon-222 and its daughter products are major sources of natural radiations and a significant total inhalation dose is related to them. Hence, the measurement of radon activity in the environment has gained an increasing importance. In this study, with the measurement of radon concentration, the indoor radon activity level and radon effective dose rate in Jooshan hot spring were determined. Concentration of radon gas inside the pool of Jooshan hot spring was measured using the active detector Rad7 type and the annual effective dose was estimated for individuals inhaling the indoor air of this pool for a specified period of time. Concentration of indoor air radon gas was 98.3 +/- 4.9 Bq/m3 and for a person staying in the pool twice a week and each time for two hours, the annual effective dose rate, due to the inhalation of radon, equals to 0.06 +/- 0.003 mSv/y. Comparison of the obtained effective dose with the standards of Environmental protection Agency and Health physics Society, it can be concluded that for individuals that normally use Jooshan hot spring pool, the resulted dose is in the recommended range

effects of internal wall covering materials on hazards of indoor radon concentrations in houses of Iran

Radon gas emanating from underground can concentrate indoor and reach levels, which represent a risk to people's health. According to WHO [World Health Organization] and ERA [Environmental Protection Agency], radon is the second leading cause of lung cancer in the world. Due to the direct correlation of lung cancer and radon exposure, it is ideal to evaluate the hazards of radon accumulation in the Iran dwellings with different materials by direct measurement of the radon concentrations using accurate, simple and fast method. The aim of this study was to measure variation of radon concentrations with different covering materials on internal building surfaces including walls, which are used in Iran dwellings. A special chamber with changeable walls of different covering materials [gypsum, wallpaper, oil dye, plastic dye, wood board, and Belka] was made. Radioactive lantern mantles were used for elevating the radon [220]Rn] levels in the chamber artificially. Ventilation in the chamber had been such way that accumulation of radon could be possible. Active measurement by Prassi portable radon gas surveyor was performed for staging purposes. The average radon concentration for wood and plastic dye was 869.0 +/- 66.7 and 936.8_60.6 [bq/m[3]], respectively, while that for wallpaper and gypsum was 449.2 +/- 101.7, 590.9 +/- 49.0 [bq/m[3]], significantly lower than other covers. The average radon concentration for oil dye and Belka cover was 668.3 +/- 42.3, 697.2 +/- 136.7 [bq/m[3]], respectively. Individuals living in a house with internal wall covering materials of gypsum and wallpaper receive an average annual dose smaller than one living in a house with internal wall covering materials of wood board and plastic dye. Using wallpaper and gypsum as an internal cover for the dwellings suggested

Exposure of school children to alpha particles

A substantial part of the public's natural radiation dose is due to the inhalation of radon gas. Most of the exposure occurs indoors where the airborne concentration of radon and its decay products is usually higher than outdoors. Radon activity concentration has been measured twice in 50 classrooms in 5 levels [10 each] during summer and winter using solid-state nuclear track detectors [CR-39]. The indoor radon levels in the classrooms were slightly higher than exclusion limits recommended by the ICRP in the first and second floors and fill within the safe limits in the higher floors, where the average radon concentrations were found to be 57.6 +/- 3.33, 48.5 +/- 3.10, 34.5 +/- 1.71, 29.7 +/- 1.33 and 25.3 +/- 1.88 Bq/m3 for first, second, third, fourth and fifth floors with good ventilation, respectively; and 78 +/- 3.23, 66.9 +/- 2.84, 40.3 +/- 1.70, 34.4 +/- 1.42 and 28.8 +/- 1.75 Bq/m[3] for classes with poor ventilation respectively. The mean annual radiation doses obtained on inhalation exposure to Rn-222 and its degradation products were 0.85 +/- 0.37 and 0.67 +/- 0.23 mSvy[-1] for classes with closed and open windows, respectively. From the results obtained it can be concluded that values of radon and its daughter products and the resulting dose in the classrooms fill within the safe limit. Poor ventilation, construction materials, and radon exhalation from the ground are the main reasons for the relatively high radon concentrations in the lower levels

Radon level in dwellings basement of Yazd-Iran

Indoor radon gas [[222]Rn] has been recognized as one of the health hazards for human. Air radon comes mainly from basement soil and construction materials. Saghand region with rich uranium mines lies 180 km from Yazd, so the indoor radon concentration can be high. Yazd, with population of about 457000, is the biggest city near Saghand, thus, indoor gamma background radiation of Yazd could be more than the other cities of Yazd province. In this study the air radon level of 84 dwellings basement from various regions of Yazd were measured during the year 2007. To do so, a portable radon gas surveyor was used which is an active measurement method. Using this device, alpha radiation of each basement was measured by a solid state detector for 24 hours. Radon concentrations of the basements were between 5.55 to 747.4 Bq/m[3] with mean of 137.36 Bq/m[3]. The mean radon concentration wasn't significantly different from the EPA guide line that is mitigation recommendations level [148 Bq/m[3]]. However, more than 30% of the basements had radon concentration more than EPA guide line. Using good air conditioning system in the dwelling basements is suggested

Environmental monitoring of radon, thoron and their progeny in some dwellings of northern Haryana (India).

The problem of randon is an important global problem of radiation hygiene concerning the world population. Radon and its progeny are the major contributors in the radiation dose received by general population of the world. Keeping this in mind, the environmental monitoring of radon, thoron and their progeny in some dwellings of northern part of Haryana state of India has been carried out. The radon thoron twin dosimeter cups were used for the study. Three pieces of LR-115 solid-state nuclear track detectors were fixed in the dosimeters and were suspended in the dwellings for three months during a season. The first detector indicated radon, thoron and progeny concentration, the second showed radon and thoron concentration, while the third detected only the radon concentration. The aim of study was to carry out possible health risk assessment in the dwellings under consideration. During summer season, the radon concentration in northern region of Haryana varied from 66-97 Bq m(-3), while the thoron concentration in the same dwellings varied from 27-65 Bq m(-3). During winter season, radon concentration in northern region of Haryana varied from 73-104 Bq m(-3) with an average of 88 + 7 Bq m(-3), while the thoron concentration in the same dwellings varied from 35-69 Bq m(-3) with an average of 55 +/- 8 Bq m(-3). The radon-thoron progeny levels and annual doses received by the inhabitants in the dwellings under study have also been calculated.

Níveis de radioatividade natural decorrente do radônio no complexo rochoso da Serra de São Vicente, SP / Levels of natural radon-radioactivity in the São Vicente, SP, rock massif

OBJETIVO: Realizar monitoração passiva e integrada do radônio em várias amostras de águas, solos e locais fechados do complexo rochoso da Serra de São Vicente, SP, com o intuito de avaliar a distribuição de ocorrência deste gás radioativo naquele local. MATERIAIS E MÉTODOS: A técnica utilizada consistiu em expor detectores plásticos policarbonatos (SSNTD) do tipo Makrofol E, na geometria de copo fechado, ao radônio emanado das amostras de águas coletadas dos solos e ao acumulado em ambientes internos (residências e cavidades nas rochas) existentes no complexo rochoso de São Vicente. RESULTADOS: Os valores obtidos para os teores de radônio variaram entre 8,1 e 36 Bq/l para as fontes de água natural, entre 68 e 610 Bq/m³ nas residências, entre 0,41 e 3,46 kBq/m³nos solos e entre 0,72 e 5,85 kBq/m³ nas cavidades do Maciço de São Vicente. CONCLUSÃO: Para algumas residências e na maioria das fontes de água estudadas, os teores de radônio encontrados neste trabalho estiveram acima dos limites máximos propostos por organismos internacionais. Recomenda-se, portanto, que ações de intervenção sejam implementadas para a dissipação do radônio, tanto nessas residências como durante a coleta das águas para fins de consumo.

OBJECTIVE: The objective of this study was to perform a passive and time-integrated radon monitoring in several soil and water samples and indoor environments of the São Vicente, SP, rock massif with the purpose of evaluating the presence and distribution of that radioactive gas in this region. MATERIALS AND METHODS: The technique employed consisted of exposing Makrofol E-type polycarbonate plastic detectors (SSNTD), using the closed cup method, to radon emanated from ground water samples and to the gas accumulated inside indoor environments (dwellings) and inside rock cavities existing in the São Vicente rock massif. RESULTS: The radon concentration values obtained ranged from 8.1 to 36 Bq/l in natural ground waters; between 68 and 610 Bq/m³ in dwellings; from 0.41 to 3.46 kBq/m³ in soils and from 0.72 to 5.85 kBq/m³ inside rock cavities of the São Vicente rock massif. CONCLUSION: In some dwellings and in most of ground water samples, the radon concentration values found in this study have exceeded the maximum levels proposed by international agencies. Thus, intervention actions are recommended for radon dissipation in dwellings and during consumption water collection.

[Air radon in Tunisia dwellings]

Radon is a natural radioactive gas produced by decay of uranium and radium present in soils. Diluted in air, in confined atmospheres, it may accumulate in high concentration. Inhalation of radio and its progeny is thought to increase lung cancer risk. For the first time, air radon concentrations were determined in 1151 dwellings situated in all the inhabited regions of Tunisia, using open alpha-track dosimeters exposed during two months. The median of 1864 measurements was 36 B[q] m[-3] [with a maximum of 512 B[q] M[-3] most of tem being less than 100 B[q] M[-3]. All results were under the International Instances recommended range

Medidas dos níveis de radônio em diferentes tipos de ambientes internos na região da Baixada Santista, SP / Measurements of radon levels in different indoor environments in Baixada Santista, São Paulo, Brazil

OBJETIVO: Exposições a altos níveis do gás radioativo radônio podem causar câncer de pulmão e, conseqüentemente, o conhecimento da concentração deste gás em ambientes internos é importante, do ponto de vista de proteção radiológica, para a população de um modo geral. Neste trabalho realizaram-se monitorações passiva e integrada de radônio em alguns tipos de ambientes fechados na região da Baixada Santista, SP, tais como túneis, galpão de fertilizantes, "shopping center", lojas de cerâmica e residências, com o objetivo de se avaliar os níveis de concentração existentes nestes locais. MATERIAIS E MÉTODOS: As medidas de concentração de radônio foram realizadas utilizando a técnica do registro de traços de partículas alfa em folhas plásticas de Makrofol E, na geometria de copo fechado ("cup method"). RESULTADOS: Os teores de radônio encontrados nos ambientes internos estudados neste trabalho variaram entre 17 e 263 Bq/m³, em razoável acordo com os valores divulgados na literatura por outros autores para ambientes similares. CONCLUSÃO: De modo geral, os resultados obtidos estão abaixo dos limites máximos recomendados pela Comissão Internacional de Proteção Radiológica (ICRP), não necessitando, portanto, que sejam implementadas ações de intervenção nos locais estudados.

A 20-year follow-up study on the effects of long-term exposure to thorium dust / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the possible effects of long-term exposure to dust containing thorium and thoron progeny on dust-exposed miners.</p><p><b>METHODS</b>A negative, high voltage, exhaled thoron progeny measurement system was used to estimate the miners' thorium lung burden.</p><p><b>RESULTS</b>The highest thorium lung burden of 638 miners was 11.11 Bq. The incidence of stage 0(+) pneumoconiosis was higher among dust-exposed miners. Lung cancer mortality of the dust-exposed miners was significantly higher than that of controls (P < 0.005).</p><p><b>CONCLUSION</b>There is a difference in cancer rates between those who have long-term exposure to dust containing thorium (in which carcinogenic ThO(2) and SiO(2) exist) and thoron progeny and those who have not.</p>

Indoor radon in Thailand: a study with particular reference to its sources.

Measurements of radon gas were carried out on each floor of the four tall concrete buildings. The results show clearly that levels of radon concentration on the higher floors of the buildings were mostly comparable and occasionally were much higher than the ground-floor in contact with the earth. Hence, the findings indicate that the source of indoor radon is not only the surrounding soil but also other sources in the buildings, i.e. most likely radium-containing building materials.