Estimating the radon concentration in water and indoor air

The paper presents the results of radon concentration measurements in the vicinity of water, indoor air and in contact to building walls. The investigations were carried out using CR-39 track detectors. Samples of ground water flowing out of many springs mostly in Arabian Gulf area except one from Germany have been studied. The results are compared with international recommendations and the values are found to be lower than the recommended value. Measuring the mean indoor radon concentrations in air and in contact to building walls in the dwellings of Kuwait University Campus were found 24.2 +/- 7.7, and 462 +/- 422 Bq m(-3) respectively. These values lead to average effective dose equivalent rates of 1.3 +/- 0.4 and 23 +/- 21 mSv year(-1), respectively.     

重庆市主城区室内氡浓度调查与评价

根据重庆市城市组团式建设特点,采用径迹法对重庆市主城建成区开展室内氡浓度调查。结果表明,各区县室内氡浓度整体水平较低,重庆市主城区室内氡浓度平均值为64.5 Bq/m3,168个采样点均小于国家标准200 Bq/m3;吸入氡及子体对人员产生的年均有效剂量均低于《住房内氡浓度控制标准》和《地下建筑氡及其子体控制标准规定》中规定的室内氡浓度行动水平。     

贵阳室内氡时空分布特征研究

为了全面分析室内氡的时空分布特征、来源和影响因素,选择了贵阳市不同地理位置的居民住宅、办公场所和公共场所,进行了为期一年的室内氡监测。贵阳市室内氡的平均浓度为(72.7±1.6)Bq/m3,低于室内空气污染国家标准,达标率98.5%。其中居民住宅、办公场所和公共场所的室内氡浓度分别为(93.46±86.93)、(74.68±40.74)、(61±26.93)Bq/m3。研究表明,室内涂料、装修程度和通风效果、小区环境等对室内氡浓度高低有显著影响,室内氡也随季节变化而发生波动。对于居民住宅和公共场所氡的室内外来源相对重要性不同。居民住宅内新楼和旧楼不同楼层室内氡的来源、影响因素和分布特征有显著差异。     

Assessment of environmental radioactivity for Batman, Turkey

The province of Batman, located in southern Anatolia, has a population of approximately 500,000. To our knowledge, there exists no information regarding the environmental radioactivity in this province. Therefore, gamma activity measurements in soil, building materials and water samples and an indoor radon survey have been carried out in the Batman province. The mean activity concentrations of the natural radionuclides (²²⁶Ra, ²³²Th and ⁴⁰K) and a fission product (¹³⁷Cs) were 35 ± 8, 25 ± 10, 274 ± 167 and 12 ± 7 Bq kg^???1, respectively, in the soil samples. The concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in the selected building materials ranged from 18 to 48 Bq kg^???1, 8 to 49 Bq kg^???1 and 68 to 477 Bq kg^???1, respectively. All the calculated radium equivalent (Ra_eq) activity values of the building material samples are lower than the limit of 370 Bq kg^???1, equivalent to a γ-dose of 1.5 mSv year^???1. The activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in tap waters collected from the study area were determined with mean specific activity concentrations of 42 ± 15, 35 ± 9 and 524 ± 190 mBq L^???1, respectively. Indoor radon measurements were made at 95 dwellings in Batman using a CR-39 detector. The radon concentration levels were found to vary from 23 to 145 Bq m^???3. The arithmetic mean of the measured radon concentration levels was found to be 84 Bq m^???3 with a standard deviation value of 23 Bq m^???3. The measurement results obtained in this study did not significantly differ from those taken in other parts of the country. The data generated in this study can be used to determine whether the Batman province is in a normal or high background radiation area and provides a valuable database for future estimations of the impact of radioactive pollution.     

Outdoor 220Rn, 222Rn and terrestrial gamma radiation levels: investigation study in the thorium rich Fen Complex, Norway

The present study was done in the Fen Complex, a Norwegian area rich in naturally occurring radionuclides, especially in thorium ((232)Th). Measurement of radioactivity levels was conducted at the decommissioned iron (Fe) and niobium (Nb) mining sites (TENORM) as well as at the undisturbed wooded sites (NORM), all open for free public access. The soil activity concentrations of (232)Th (3280-8395 Bq kg(-1)) were significantly higher than the world and the Norwegian average values and exceeded the Norwegian screening level (1000 Bq kg(-1)) for radioactive waste, while radium ((226)Ra) was present at slightly elevated levels (89-171 Bq kg(-1)). Terrestrial gamma dose rates were also elevated, ranging 2.6-4.4 μGy h(-1). Based on long-term surveys, the air concentrations of thoron ((220)Rn) and radon ((222)Rn) reached 1786 and 82 Bq m(-3), respectively. Seasonal variation in the outdoor gamma dose rates and Rn concentrations was confirmed. Correlation analyses showed a linear relationship between air radiation levels and the abundance of (232)Th in soil. The annual outdoor effective radiation doses for humans (occupancy 5 h day(-1)) were estimated to be in the range of 3.0-7.7 mSv, comparable or higher than the total average (summarized indoor and outdoor) exposure dose for the Norwegian population (2.9 mSv year(-1)). On the basis of all obtained results, this Norwegian area should be considered as enhanced natural radiation area (ENRA).     

Estimation of uranium and radon concentration in some drinking water samples of Upper Siwaliks, India

Uranium and radon concentration was assessed in water samples taken from hand pumps, natural sources and wells collected from some areas of Upper Siwaliks, Northern India. Fission track registration technique was used to estimate the uranium content of water samples. The uranium concentration in water samples was found to vary from 1.08 +/- 0.03 to 19.68 +/- 0.12 microg l(-1). These values were compared with safe limit values recommended for drinking water. Most of the water samples were found to have uranium concentration below the safe limit of 15 microg l(-1) (WHO, World Health Organization, Guidelines for drinking-water quality (3rd ed.). Geneva, Switzerland: WHO, 2004). The radon estimation in these water samples was made using alpha-scintillometry to study its correlation with uranium. The radon concentration in these samples was found to vary from 0.87 +/- 0.29 to 32.10 +/- 1.79 Bq l(-1). The recorded values of radon concentration were within the recommended safe limit of 4 to 40 Bq l(-1) (UNSCEAR, United Nations Scientific Committee on the Effects of Atomic Radiations, Sources and effects of ionizing radiation. New York: United Nations, 1993). No direct correlation was found between uranium concentration and radon concentration in water samples belonging to Upper Siwaliks. The values of uranium and radon concentration in water were compared with that from the adjoining areas of Punjab state, India.     

Assessing radon concentrations in areas with few measurements

The New York State Department of Health has estimated and mappedradon concentrations for every town and city in the State. Sincefor many towns there are few indoor radon measurements, the radonestimates for these towns were determined using correlations to surficial geology. A project was conducted to target towns for additional measurements that currently have few data but, based on the surficial geology of the town, are estimated to have elevated levels of indoor radon. The objective of the project wasto obtain at least 30 additional measurements for the targeted towns and to compare the measurement results with the estimates based on geology. The study completed 1606 radon measurements from 9080 detector applications mailed to home owners in 94 underserved towns spread throughout the State. Of the 1115 basement measurements, 43% exceeded 148 Bq m^-3, with a maximum of 6900 Bq m^-3. Three homes measured in one town hadradon concentrations above 2900 Bq m^-3. Of the 491 living-area measurements, 19% exceeded 148 Bq m^-3, with a maximum of 2700 Bq m^-3. About 60% and 86% of measurementresults were within one standard deviation and a factor of two,respectively, of estimated concentrations. Results indicate thatregardless of the magnitude of radon potential, the estimates arein good agreement with measured concentrations.     

Indoor radon measurement and effective dose assessment of 150 apartments in Mashhad,Iran

Environmental monitoring and indoor radon measurement are important for public health, to estimate the cancer risk of respiratory system and, if necessary, to suggest proper methods that reduce indoor radon level. In this research, indoor radon concentration in the air has been measured in 150 apartments in Mashhad city. The result demonstrates about 94.7% of apartments have radon concentration less than 100 Bq/m³, taken by WHO as the action level, and 5.3% have the concentration higher than this level. As well as, annual radon dose has been assessed using the equation for annual effective dose calculation introduced by United Nations Scientific Committee on the Effects of Atomic Radiation.     

Radon (thoron) daughter measurements with an automated,programmable, radiation monitor

A technical evaluation of an automated, programmable, grab-sampler manufactured by Pylon Electronic Development under the commercial name WL-1000C has been conducted. Six different methods are implemented in the instrument for analyzing radiation data. Any one method can be used on command and easily selected by means of a keyboard. Available radiation data that can be retrieved on command include radon (thoron) daughter concentrations and radon (thoron) Working Levels. Measurements were carried out under laboratory-controlled conditions in a large (26 m³) radon/thoron test facility, designed for calibration purposes, and at an underground uranium mine. Data obtained with the WL-1000C have been compared with conventional grab-sampling (e.g., Kusnetz, Thomas-Tsivoglou and Markov methods) and with other automated radiation instrumentation previously tested at our laboratories. Tests were done under constant radiation conditions and also under rapidly fluctuating conditions in order to determine the response of the instruments and methods in these two cases of practial interest. The Working Level used in these experiments was in the approximate range of 0.01 to 10 WL. Tests were conducted under a variety of environmental conditions. Good agreement with grab-sampling data was found for radon daughters. Some discrepancies with grab-sampling data were found for radon daughter/thoron daughter mixtures. Disagreement in the latter case is to be expected because of -energy overlap between RaA and ThC.     

Simultaneous measurements of radon and thoron,and their progeny levels in dwellings on anticlinal structures of Assam,India

Radon and thoron, and their progeny concentrations along with equilibrium factors for gas progeny and radiological risks to the residents have been measured in dwellings of Digboi and Mashimpur areas located on anticlines during the winter season. In this present investigation, twin-cup dosemeters fitted with LR-115 (II) nuclear detectors have been employed. The present work has shown that there exist considerable house-to-house variations in values with maximum values in mud houses and minimum values in assam type (AT) houses. It has been found that mean (and geometric standard deviations (GSD)) radon concentrations are 83.8 (1.3), 113.5 (1.1) and 157.2 (1.2) Bq m^?3 in AT, reinforced cement concrete (RCC) and mud houses in Digboi area and 63.0 (1.1), 87.1 (1.4) and 182.1 (1.2) Bq m^?3 in AT, RCC and mud houses in Mashimpur area, respectively. The overall mean radon concentrations in Digboi and Mashimpur are estimated to be 114.4 (1.4) and 100.0 (1.7) Bq m^?3. The mean radon concentrations are found to be less than the lower reference level of 200 Bq m^?3 of the International Commission on Radiological Protection (ICRP 2007). The thoron concentrations in Digboi area are estimated to be 31.1 (1.3), 50.8 (1.4) and 67.0 (1.6) Bq m^?3 in AT, RCC and mud houses, respectively, whereas in Mashimpur area, the thoron concentrations are estimated to be 26.4 (1.3), 44.4 (1.3) and 77.7 (1.3) Bq m^?3 in AT, RCC and mud houses, respectively. The mean annual effective doses in Digboi area are found to be 1.9 (1.3), 2.7 (1.2) and 4.1 (1.4) mSv y^?1 in AT, RCC and mud houses, respectively, while in the case of Mashimpur area, the mean annual effective doses are found to be 1.5 (1.4), 2.2 (1.2) and 4.9 (1.3) mSv y^?1 in AT, RCC and mud houses, respectively. Nevertheless, the obtained results are much lower than the upper reference level of 10 mSv (ICRP 2007).     

Determination of the working level of radon/thoron mixtures by personal α-dosimeters and environmental α-monitors using gross α-counting

Analytical procedures are presented which permit the determination of the Working Levels of the radon and thoron progenies with personal α-dosimeters and α-particle environmental monitors, operating on time integrating principles, from gross α-counts. Experiments have been carried out in an underground uranium mine and in a radon/thoron environmental chamber, specially designed for calibration purposes, to verify theoretical data. In general, and notwithstanding a number of complicating factors, fair to good agreement has been found between theoretical and experimental data. Experimental values have been found to be lower than theoretical values, an observation which is partly ascribed to plate-out of decay products in the instrument's sampling heads.     

Radon, helium and uranium survey in some thermal springs located in NW Himalayas, India: mobilization by tectonic features or by geochemical barriers?

Radon, helium and uranium measurements have been carried out in hot water springs in the Parbati and Beas valleys of Himachal Himalaya. Most of these hot springs are known as famous pilgrimage centers. The activity of dissolved radon in the liquid phase is found to vary widely, by an order of magnitude, between 10 and 750 Bq L(-1), whereas, the dissolved helium content in these thermal springs varies between 10 and 100 ppm. The uranium contents are low and vary from <0.01 to 5 microg L(-1). The measured values of radon, helium and uranium are possibly controlled by structural geology, namely the presence of pervious fault systems, and by the lithology of the leached host rocks. Redox-potential geochemical barriers cause the mobilization of uranile ions in solution (UO2+); the most plausible hypothesis is when the conditions are oxidising, confirming the importance of physico-chemical conditions up to the supergenic environment, to control the fluid geochemistry of the U-He-222Rn system. Some evidence is available from both geothermometric considerations and geochemical data which will be reported elsewhere, whereas the present study is focused on U decay series-noble gas geochemistry. The first analysis of collected 3He/4He data is consistent with a crustal signature at the studied thermal springs.     

Gamma dose measurement in dwellings of Agastheeswaram Taluk of Kanyakumari district, lying 30 km Radius from Kudankulam nuclear power plant site

Most of the building materials contain naturally occurring radioactive elements, the most important of which are potassium ⁴⁰K and the members of two natural radioactive series, which can be represented by the isotopes of thorium ²³²Th and Uranium ²³⁸U. The presence of these radioisotopes in the materials causes external exposure to the people who live in the building. In addition, the disintegration of Uranium ²³⁸U increases the concentration of radon gas ²²²Rn and of its daughters in the house. So a systematic indoor gamma dose measurement has been performed in the dwellings of Agastheeswaram Taluk of Kanyakumari district, which is lying within the 30 km radius from the upcoming Kudankulam nuclear power plant site. The geometric mean of annual absorbed dose from gamma radiation in dwellings has been found to be 278 nGyh⁻¹. The seasonal variation of indoor gamma dose measurements has also been studied. Significant differences have been observed in dwellings built of different materials such as concrete, tiled, etc.     

Background concentrations of individual and total volatile organic compounds in residential indoor air of Schleswig-Holstein, Germany

During a monitoring campaign concentrations of volatile organic compounds (VOCs) were measured in indoor air of 79 dwellings where occupants had not complained about health problems or unpleasant odour. Parameters monitored were the individual concentration of 68 VOCs and the total concentration of all VOCs inside the room. VOCs adsorbed by Tenax TA were then analysed by means of thermal desorption, gas chromatography and mass spectrometry. The analytical procedure and quantification was done according to the recommendation of the ECA-IAQ Working Group 13 which gave a definition of the total volatile organic compound (TVOC) concentration. Using this recommendation TVOC-concentrations ranged between 33 and 1600 microg m(-3) with a median of 289 microg m(-3). Compounds found in every sample and with the highest concentrations were 2-propanol, alpha-pinene and toluene. Save for a few samples, all concentrations measured have been a factor 2 to 10 lower, compared to data from similar studies. Only a few terpenes and aldehydes were found exceeding published reference data or odour threshold concentrations. However, it has been found that sampling and analysing methods do have a considerable impact on the results, making direct comparisons of studies somewhat questionable. 47% of all samples revealed concentrations exceeding the threshold value of 300 microg TVOC m(-3) set by the German Federal Environmental Agency as a target for indoor air quality. Using the TVOC concentration as defined in the ECA-IAQ methodology is instrumental in assessing exposure to VOCs and identifying sources of VOCs. The background concentrations determined in this study can be used to discuss and interpret target values for individual and total volatile organic compounds in indoor air.     

Soil gas radon analysis in some areas of Northern Punjab, India

The radon concentration levels in soil samples from 39 locations of Northern Punjab are measured using AlphaGUARD (PQ 2000 PRO Model) of Genitron instruments, Germany. The radon concentration in soil varies from 0.3 to 35.8 kBq/l. The minimum value of radon is observed in Talwandi Choudhrian and is maximum for Nushera Dhala. The soil gas radon is correlated with soil temperature, pressure, and humidity to observe the effect of these parameters on radon release. The soil gas radon values in the study area are compared with that obtained in groundwater. The results are also compared with the available radon data for other parts of Punjab and Himachal Pradesh.     

Long-term investigations of post-Chernobyl radiocaesium in fallout and air in North Croatia

The long-term behaviour of (137)Cs activity concentrations in air and fallout has been studied in the city of Zagreb for the post-Chernobyl period (1986-2006) as a part of an extended monitoring program of radioactive contamination of human environment in Croatia. Annual mean (137)Cs activity concentrations in air and annual total deposition fluxes (wet plus dry) decreased from 2.8 x 10(-4) Bq m(-3) in September 1986 to 3.0 x 10(-6) Bq m(-3) in last quarter of 2006 and from 6,410 Bq m(-2) year(-1) in 1986 to 2 Bq m(-2) year(-1) in 2006 respectively. By fitting the measured (137)Cs activity concentrations to the theoretical curve the ecological half-lives of (137)Cs in air and fallout were estimated with respective values of 0.46 and 0.54 years for immediate post-Chernobyl period, increasing to 5.52 and 3.97 years afterwards. Using the data on (137)Cs activity concentrations in air and fallout total caesium deposition velocity of (3.34 +/- 3.13) x 10(-2) ms(-1) was estimated with median value being 2.13 x 10(-2) ms(-1). Such relatively high (137)Cs deposition velocities compared with pre-Chernobyl ones, are characteristic for the post-Chernobyl period and, according to Stokes' settling law, indicate that the diameters of aerosol particles associated with (137)Cs originated from the Chernobyl accident are pretty large, i.e. >1 microm. (134)Cs/(137)Cs activity ratio in fallout and in air has been found to be similar to the theoretically predicted values, initial value being about 0.5 and decreasing according to differential radioactive decay. The similar ratio has been observed in most of the other environmental samples.     

A positive chemical ionization GC/MS method for the determination of airborne ethylene glycol and propylene glycols in non-occupational environments

An analytical method for ethylene glycol and propylene glycols has been developed for measuring airborne levels of these chemicals in non-occupational environments such as residences and office buildings. The analytes were collected on charcoal tubes, solvent extracted, and analyzed by gas chromatography-mass spectrometry using a positive chemical ionization technique. The method had a method detection limit of 0.07 microg m(-3) for ethylene glycol and 0.03 microg m(-3) for 1,2- and 1,3-propylene glycols, respectively, based on a 1.44 m3 sampling volume. Indoor air samples of several residential homes and other indoor environments have been analyzed. The median concentrations of ethylene glycol and 1,2-propylene glycol in nine residential indoor air samples were 53 microg m(-3) and 13 microg m(-3) respectively with maximum values of 223 microg m(-3) and 25 microg m(-3) detected for ethylene glycol and 1,2-propylene glycol respectively. The concentrations of these two chemicals in one office and two laboratories were at low microg m(-3) levels. The maximum concentration of 1,3-propylene glycol detected in indoor air was 0.1 microg m(-3).     

Radiological study of exposure levels in El Maghara underground coal mine

Coal is largely composed of organic matter, but it is the inorganic matter in coal minerals and trace elements that have been cited as possible causes of health, environmental and technological problems associated with the use of coal. Some trace elements in coal are naturally radioactive. These radioactive elements include uranium (U), thorium (Th) and their numerous decay products, including radium (Ra) and radon (Rn). Although these elements are less chemically toxic than other coal constituents, such as arsenic, selenium or mercury, questions have been raised concerning the possible risk from radiation. In order to accurately address these questions and to predict the mobility of radioactive elements during the coal fuel cycle, it is important to determine the specific activity, distribution and form of radioactive elements in coal. The assessment of the radiation exposure from coal burning is critically dependent on the specific activity of radioactive elements in coal and in the fly ash that remains after combustion. The El-Maghara coal mine is the only producing coal mine in Egypt. It is located in the middle of the Sinai desert about 250 km north-east of Cairo, where a coal-fired power plant is intended to be built. In this study, a pre-operational radiological baseline of the site and the occupational radiation exposures due to radon progeny in the mine were determined. The specific activities of 226Ra, 232Th and 40K in soil and coal dust samples collected along the main gallery ranges were found to be 6-22.9, 9.6-47.3 and 77-489 Bq kg-1, respectively. Soil samples collected around the mine showed concentrations of 226Ra, 232Th and 40K in the ranges 2.7-20.2, 3.2-12.6 and 14.6-201 Bq kg-1, respectively. All of the mean values of radon progeny were lower than the action levels for working places recommended in the International Commission on Radiological Protection (ICRP) 65.     

成都市土壤天然放射性核素的外照射水平估算研究

利用IED22000A便携式微机多道能谱仪对成都市区土壤的天然放射性核素进行了直接就地测量，估算出天然环境放射性核素^238U、^232Th、^40K的比活度范围分别为10.37～77．19Bq／kg、17，85～225．74Bq／kg、284．83～892．67Bq／kg；外照射指数范围为0．16—0．8；离地面1m高的空气吸收剂量率均值为83．23nGy／h；1外照射年有效剂量当量为0．34～0．70mSv；等效镭浓度的变化范围是59．06-386．45Bq／kg，均值为164．15Bq／kg。各项指标均在容许范围之内，因而成都市属于外照射水平的安全区域，人居环境不受影响。     

Determination of selected microbial volatile organic compounds by diffusive sampling and dual-column capillary GC-FID--a new feasible approach for the detection of an exposure to indoor mould fungi?

A new, analytically valid procedure is described to assess the exposure of human beings to the so-called microbial volatile organic compounds (MVOCs) in air. The method can be used routinely for large sample numbers and is especially valuable as a basis for further research on the correlation between single MVOCs and indoor mould growth. The procedure is based on the fact that fungi produce a variety of volatile organic compounds, such as 3-methylbutan-1-ol, 3-methylbutan-2-ol, fenchone, heptan-2-one, hexan-2-one, octan-3-one, octan-3-ol, pentan-2-ol, alpha-terpineol, and thujopsene, which they emit into the indoor environment. Using diffusive samplers, these MVOCs are adsorbed onto charcoal during a sampling interval of four weeks. The described method is thus superior to existing methods which use short-term active sampling. After desorption with carbon disulfide, the MVOCs were determined by dual-column gas chromatography with flame ionization detection using the large-volume injection technique for sample introduction. The detection limits ranged between 0.15 and 0.53 microgram m-3, within-series precision was found to range between 6.5 and 19.0%, and recovery was between 77 and 118%. The procedure has been successfully applied in the context of a large field study to measure the indoor MVOC exposure in children's rooms of 132 dwellings. The objective of the study was to examine the relation between indoor mould growth, the indoor MVOC exposure and the prevalence of adverse health effects. Information about mould formation has been obtained by a questionnaire and by the determination of colony forming units of mould fungi in mattress dust. With the exception of 3-methylbutan-2-ol, fenchone, nonan-2-one, octan-2-one, and thujopsene, indoor air concentrations of all MVOCs under investigation were significantly higher inside damp and mouldy dwellings. From the primary MVOCs under investigation, 3-methylbutan-1-ol, hexan-2-one, heptan-2-one, and octan-3-ol were found to be most reliable indicators for mould formation. A correlation was also found between selected MVOCs and the occurrence of mould species in mattress dust. Aspergillus sp. correlated with heptan-2-one, hexan-2-one, octan-3-ol, octan-3-one, and alpha-terpineol, while the occurrence of Eurotium sp. was correlated with higher indoor air concentrations of 3-methylbutan-1-ol, 3-methylbutan-2-ol, heptan-2-one, hexan-2-one, octan-3-ol, and thujopsene. Children living in dwellings with elevated MVOC levels had a higher prevalence of asthma, hay fever, wheezing, and irritations of the eyes. These positive associations persisted after controlling for confounding factors such as age, sex, body-mass index, number of siblings, social status, passive smoking, type of heating, and ventilation habits. However, they were not statistically significant. This lack of significance may be a result of the small number of investigated samples.