Radon survey and soil gamma doses in primary schools of Batman,Turkey

A survey was conducted to evaluate levels of indoor radon and gamma doses in 42 primary schools located in Batman, southeastern Anatolia, Turkey. Indoor radon measurements were carried out using CR-39 solid-state nuclear track detector-based radon dosimeters. The overall mean annual ²²²Rn activity in the surveyed area was found to be 49 Bq m^?3 (equivalent to an annual effective dose of 0.25 mSv). However, in one of the districts (Besiri) the maximum radon value turned out to be 307 Bq m^?3. The estimated annual effective doses are less than the recommended action level (3–10 mSv). It is found that the radon concentration decreases with increasing floor number. The concentrations of natural and artificial radioisotopes were determined using gamma-ray spectroscopy for soil samples collected in close vicinity of the studied schools. The mean gamma activity concentrations in the soil samples were 31, 25, 329 and 12 Bq kg^?1 for ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs, respectively. The radiological parameters such as the absorbed dose rate in air and the annual effective dose equivalent were calculated. These radiological parameters were evaluated and compared with the internationally recommended values.     

In situ measurements of radon levels in water and soil and exhalation rate in areas of Malwa belt of Punjab (India)

Radon concentration levels in water and soil gas from 36 locations pertaining to some areas of Malwa region of Punjab have been measured on an in situ basis using a continuous active radon detector (AlphaGuard, Model – PQ 2000 PRO, Genitron instruments, Germany). Exhalation rate measurements have also been carried out at these places, using a closed-circuit technique. The radon concentrations in soil and water varied from 1.9 to 16.4 kBq m^?3 and 5.01 to 11.6 kBq m^?3, respectively. The exhalation rate (E _Rn) ranged between 7.48 and 35.88 mBq m^?2 s^?1 with an average value of 18.17 mBq m^?2 s^?1. Annual dose rates have been calculated for water radon concentrations. The minimum to maximum values of dose rates were found to be 13.42–31.08 μSv y^?1. The recorded values of radon concentration in water are within the safe limit of 11 Bq l^?1 recommended by the US Environment Protection Agency [National Research Council, Risk Assessment of Radon in Drinking Water (Academy Press, Washington, DC, USA, 1999)]. All measurements were made in similar climatic and environmental conditions to ensure minimal variations in meteorological parameters. An intermediate correlation coefficient (0.5) was observed between radon exhalation rates and soil gas values.     

The potential health hazard due to elevated radioactivity in old uranium mines in Dolina Białego,Tatra Mountains,Poland

Natural radioactivity is one of the essential components of the environment. Unlike the Sudety mountains area in Poland, the Tatra Mountains were not the subject of wide survey as regards the levels of natural radioactivity. Especially, the concentrations of radon (natural radioactive gas) have not been investigated there in terms of their possible negative health impact. Within the frame of bilateral cooperation between the Institute of Nuclear Physics in Kraków, Poland, and the Jo?ef Stefan Institute in Ljubljana, Slovenia, the measurements of natural radioactive elements in old uranium mines in the Tatra National Park were performed in June 2010. The investigated sites were located in Dolina Bia?ego (The Valley of the White). One of the mines is situated near the tourist path. The paper presents the results of complex measurements of natural radioactivity in both uranium drifts. The concentration of radon gas inside the mining drifts exceeded 28,000 Bq m^?3. Also, very high gamma dose rates were observed (up to 5600 nSv h^?1). The maximum concentrations of natural radioactive elements (potassium ⁴⁰K, radium ²²⁶Ra, thorium ²³²Th) in rock samples amounted to 535, 2137, and 18 Bq kg^?1, respectively. The effective dose rates due to radon and thoron inhalation have been assessed as 0.013 mSv h^?1 (for the lowest concentration) and 0.121 mSv h^?1 (for the highest concentration).     

Measurements of radon concentration in drinking water samples from Kastamonu (Turkey)

Concentration of ²²²Rn was determined in selected natural spring and tap water samples collected during spring and summer seasons from Kastamonu, Turkey. The aim of this work was to produce a map of the radon concentrations in water sources of the province and to determine any potential radiological risk for the local population. Radon measurements were performed by an AlphaGUARD radon gas analyser. The average radon concentrations were found to vary from 0.39±0.02 to 12.73±0.39 Bq l^?1 for natural springs and from 0.36±0.04 to 9.29±0.45 Bq l^?1 for tap water in spring, from 0.50±0.09 to 19.21±1.00 Bq l^?1 for natural springs and from 0.31±0.03 to 13.14±0.38 Bq l^?1 for tap water in summer. Furthermore, the results are compared with international recommendations and concentrations reported for other countries. Doses resulting from the consumption of these waters were calculated. The effective dose equivalents due to the intake of the ²²²Rn present in these waters are expected to range from 0.93 to 32.54 μSv y^?1 in summer and from 0.80 to 49.09 μSv y^?1 in spring.     

Time variations of 222Rn concentration and air exchange rates in a Hungarian cave

A long-term radon concentration monitoring was carried out in the Pál-v?lgy cave, Budapest, Hungary, for 1.5 years. Our major goal was to determine the time dependence of the radon concentration in the cave to characterise the air exchange and define the most important environmental parameters that influence the radon concentration inside the cave. The radon concentration in the cave air was measured continuously by an AlphaGuard radon monitor, and meteorological parameters outside the cave were collected simultaneously. The air's radon concentration in the cave varied between 104 and 7776?Bq?m(-3), the annual average value was 1884±85?Bq?m(-3). The summer to winter radon concentration ratio was as high as 21.8. The outside air temperature showed the strongest correlation with the radon concentration in the cave, the correlation coefficient (R) was 0.76.     

Measurements of Environmental Radon-222 Concentrations in Indoors and Outdoors in Egypt

The major contribution to population exposure from natural radiation arises from the inhalation of the decay products of radon. Substantial surveys are being conducted by several investigators to estimate the indoor and outdoor exposure nationally and to discover regional variations. In this work, radon concentration in the indoor and outdoor air was determined using the can technique and employing CR-39 solid state nuclear track detector for lengthy exposures. The range of radon-222 activity in this survey was 54 … 299 pCi · m^?3 in Cairo, 22 … 171 pCi · m^?3 in Alexandria and 89 … 370 pCi · m^?3 in Asiut. Measurements carried out in Aswan and Sinai ranged between 98 … 411 pCi · m^?3. Values of indoors and outdoors radon concentrations were found to vary with geographic location, season and height above ground. Further work is going on to study the different parameters affecting the levels of the environmental radon.     

Assessment of health hazard due to natural radioactivity in Kluang District,Johor, Malaysia

The radiation survey of the ambient environment was conducted using two gamma detectors, and the measurement results were used in the computation of the mean external radiation dose rate, mean-weighted dose rate and annual effective dose, which are 144 nGy h^?1, 0.891 mSv y^?1 and 178 μSv, respectively. A high-purity germanium detector was used to determine the activity concentrations of ²³²Th, ²²⁶Ra and ⁴⁰K in soil samples. The results of the gamma spectrometry of the soil samples show radioactivity concentration ranges from 19±1 to 405±13 Bq kg^?1 with a mean value of 137±5 Bq kg^?1 for ²³²Th, from 21±2 to 268±9 Bq kg^?1with a mean value of 78±3 Bq kg^?1 for ²²⁶Ra and from 23±9 to 1268±58 Bq kg^?1 with a mean value of 207±13 Bq kg^?1 for ⁴⁰K. Radium equivalent activity (Ra_eq) and external hazard index (H_ex) were 290 Bq kg^?1 and 0.784, respectively, which were safe for the population. The mean lifetime dose and lifetime cancer risk for each person living in the area with average lifetime (70 y) were 12.46 mSv and 7.25×10^?4 Sv year, respectively. The results were compared with values given in United Nations Scientific Committee on the Effects of Atomic Radiation 2000.     

Measurements of radon concentration levels in thermal waters in the region of Konya,Turkey

²²²Rn (radon) is one of the most important sources of natural radiation to which people are exposed. It is an alpha-emitting noble gas and it can be found in various concentrations in soil, air and in different kinds of water. In this study, we present the results of radon concentration measurements in thermal waters taken from the sources in the region of Konya located in the central part of Turkey. The radon activity concentrations in 10 thermal water samples were measured by using the AlphaGUARD PQ 2000PRO radon gas analyser in spring and summer of the year 2012. We found that radon activity concentrations range from 0.60±0.11 to 70.34±3.55 kBq m^?3 and from 0.67±0.03 to 36.53±4.68 kBq m^?3 in spring and summer, respectively. We also calculated effective doses per treatment in the spas for the spring and summer seasons. It was found that the minimum and maximum effective doses per treatment are in the range of 0.09–10.13 nSv in spring and in the range of 0.1–5.26 nSv in summer.     

Radon and thoron levels,their spatial and seasonal variations in adobe dwellings – a case study at the great Hungarian plain

Radon and thoron isotopes are responsible for approximately half of the average annual effective dose to humans. Although the half-life of thoron is short, it can potentially enter indoor air from adobe walls. Adobe was a traditional construction material in the Great Hungarian Plain. Its major raw materials are the alluvial sediments of the area. Here, seasonal radon and thoron activity concentrations were measured in 53 adobe dwellings in 7 settlements by pairs of etched track detectors. The results show that the annual average radon and thoron activity concentrations are elevated in these dwellings and that the proportions with values higher than 300 Bq m^?3 are 14–17 and 29–32% for radon and thoron, respectively. The calculated radon inhalation dose is significantly higher than the world average value, exceeding 10 mSv y^?1 in 7% of the dwellings of this study. Thoron also can be a significant contributor to the inhalation dose with about 30% in the total inhalation dose. The changes of weather conditions seem to be more relevant in the variation of measurement results than the differences in the local sedimentary geology. Still, the highest values were detected on clay. Through the year, radon follows the average temperature changes and is affected by the ventilation, whereas thoron rather seems to follow the amount of precipitation.     

Transfer of radioactivity from soil to vegetation in Rechna Doab,Pakistan

In Rechna Doab, samples of the most common vegetation, perennial grass Desmostachya bipinnata (dab), were collected along with soil samples from 29 sites. Natural radioactivity of ²²⁶Ra, ²³²Th/²²⁸Ac and ⁴⁰K was measured by using high purity germanium-based gamma ray spectrometer. Activity concentration levels of ²²⁶Ra, ²³²Th/²²⁸Ac and ⁴⁰K in soil were found to be 46.8±6.2 (36.0–57.6), 61.4±5.9 (48.2–73.2) and 644.8±73.9 (537.7–868.4) Bq kg^?1 (dry mass), respectively, and those in vegetation were 2.74±1.70 (1.00–6.39), 2.24±0.59 (1.56–2.61) and 172.72±113.37 (53.14–469.24) Bq kg^?1 (dry mass), respectively. The measured values of the activity concentration in vegetation are comparable with some other international data. Calculated soil to vegetation transfer factors of ²²⁶Ra, ²²⁸Ac and ⁴⁰K were 0.06±0.03 (0.02–0.14), 0.04±0.01 (0.03–0.04) and 0.26±0.16 (0.09–0.69). The mean outdoor absorbed dose rate in air for the area under study was determined as 8.22 nGy h^?1 and the mean indoor absorbed dose rate in air was 11.52 nGy h^?1. The total annual effective dose to the general public from the vegetation was found to be (0.02–0.16) mSv, which is below the recommended limit value of 1 mSv y^?1 for the general public. The dab vegetation under study was found to be radiologically safe for the population and environment.     

Radioactivity measurements in the environment of the Udhampur area,Jammu and Kashmir Himalayas,India

LR-115 plastic track detectors have been used for the measurement of radon exhalation rate and radium concentration in soil samples collected from some villages of the Udhampur district, Jammu and Kashmir, India. Uranium concentration has also been determined in these soil samples using the fission track registration technique. Radium concentration in soil samples varies from 5.46 to 19.17 Bqkg^?1, whereas uranium concentration varies from 2.53 to 3.65 ppm. The radon exhalation rate in these samples has been found to vary from 6.42 to 22.47 mB kg^?1 hr^?1. The work is undertaken for health risk assessments due to uranium and radium in the study area. A positive correlation has been observed between uranium and radium, as well as uranium and radon exhalation rate in soil samples.     

Radioactive analysis and radiological hazards in different types of Egyptian cement

Studies of the natural γ-emitting radionuclides in different types of cements manufactured by different companies in Egypt (e.g. Iron (HI), Karnak (HK), and Super fine (HSu) products from Helwan Ltd.) have been done to determine their natural levels of radioactivity using a high-purity germanium detector (HPGe). Knowledge of radioactivity present in cement materials enables one to assess any possible radiological risks to human health. The results show that the highest mean values of ²²⁶Ra and ²³²Th activity are 234.01±20.12 and 46.56±4.65 Bq kg^?1, respectively, measured in cement sample ‘Iron’ from Helwan company (HI). The corresponding value of ⁴⁰K is 333.53±26.68 Bq kg^?1 measured in cement sample ‘Karnak’ from Helwan company (HK). For ¹³⁷Cs, this value is 3.27±0.31 Bq kg^?1 measured in cement sample (HI). The average concentrations of measured radionuclides in the different cement samples are 72.21±6.39, 24.98±2.24, 134.49±10.45, and 0.58±0.08 Bq kg^?1 for ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs, respectively. The measured activity concentrations for these radionuclides were compared with the reported data of other countries. Radium equivalent (Ra_eq) activities and different hazard indices were calculated to assess the radiation hazard. Iron HI cement sample shows a higher Ra_eq activity of 311.91±31.10 Bq kg^?1. Calculations of absorbed doses in nGy h^?1 show that the Iron (HI), Karnak (HK), and Super fine (HSu) products from Helwan company have higher activities than the permissible level (80 nGy h^?1). On the basis of the external hazard index (H _ex), Ra_eq activities, and annual effective dose rates for organs (H _organ), the natural radioactivity of cement samples is not greater than the recommended values in the established standards and hence safe for use in building constructions and therefore for inhabitants.     

Natural radionuclide concentrations in soils around Baoji coal-fired power plant,China

Radionuclides are released together with fly ash from the coal-fired power plant and thus add to the natural radiation. Fifty soil samples were collected around the Baoji coal-fired power plant from 25 locations and the natural radionuclide concentrations were determined by a gamma ray spectrometric system. The results show that the activity concentrations in soil samples range from 12.54 to 40.18 Bq kg^?1, 38.02 to 72.55 Bq kg^?1 and 498.02 to 1126.98 Bq kg^?1 for ²²⁶Ra, ²³²Th and ⁴⁰K with the mean values of 27.35, 52.66 and 764.72 Bq kg^?1, respectively. In order to evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity (Ra_eq), the absorbed dose rate (D) and the annual effective dose rate have been calculated and compared with the internationally approved values. The radium equivalent activity in all the soil samples is lower than the safe limit set in the Organization for Economic Cooperation and Development report (370 Bq kg^?1). The average value of the calculated dose rates is higher than the global average value 55 nGy h^?1, and the calculated annual effective dose rate is significantly lower than the average annual external effective dose rate (460 μSv y^?1) of the normal background radiation.     

Measurement of radionuclides and absorbed dose rates in soil samples of Peshawar,Pakistan, using gamma ray spectrometry

The analysis of gamma-emitting radionuclides in nature, i.e. ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs, has been carried out in soil samples collected from Peshawar University Campus and surrounding areas using a high purity germanium detector coupled with a computer-based high-resolution multichannel analyser. The activity concentrations in soil ranged from 30.20±0.65 to 61.90±0.95, 50.10±0.54 to 102.80±1.04, 373.60±4.56 to 1082±11.38 and 9.50±0.11 to 46.60±0.42 Bq kg^?1 for ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs, with a mean value of 45±7.70, 67±12.50, 878±180 and 19±9.20 Bq kg^?1, respectively. The radium equivalent activity, internal and external hazard indices have mean values of 203.40±29.40 Bq kg^?1, 0.56 and 0.68, respectively. The mean values of outdoor and indoor absorbed dose rates in air and the annual effective dose equivalents were found to be 106.50 and 128 nGy h^?1 and 0.19 and 0.54 mSv y^?1, respectively. In the present study, ⁴⁰K was the major radionuclide present in soil samples. The presence of ¹³⁷Cs indicates that this area also received some fallout from the nuclear accident of the Chernobyl power plant in 1986. The activity concentrations of radionuclides found in soil samples during the current investigation were nominal. Therefore, they are not associated with any potential source of health hazard to the public.     

Radon in soil and its concentration in the atmosphere around Mysore city, India

Radon concentration in soil-gas and in the atmospheric air has been studied around Mysore city (12°N and 76°E) using Solid State Nuclear Track Detectors. The radon in soil-gas is found to be higher at a depth of 1 m than at a depth of 0.5 m from the ground surface. The higher radon concentration in soil was observed near Chamundi Hills and Karigatta village with average values of 5.94 kBq.m⁻³ and 5.32 kBq.m⁻³ at 1 m depth from the ground surface. Seasonal variations in radon in soil gas shows that, the concentration is lower in summer with an average value of 0.60 kBq.m⁻³ and higher in monsoon season with an average value of 4.70 kBq.m⁻³. Estimation of ²²⁶Ra in soil at these locations is also made using HPGe detector. The activity of ²²⁶Ra, varies from 4.82 to 74.23 Bq.kg⁻¹ with an average value of 32.11 Bq.kg⁻¹. Radon concentrations in soil-gas shows good correlation with the activity of ²²⁶Ra in soil with a correlation coefficient of 0.76     

Simultaneous measurements of indoor radon and thoron and inhalation dose assessment in Douala City,Cameroon

ABSTRACT

Radon, thoron and associated progeny measurements have been carried out in 71 dwellings of Douala city, Cameroon. The radon–thoron discriminative detectors (RADUET) were used to estimate the radon and thoron concentration, while thoron progeny monitors measured equilibrium equivalent thoron concentration (EETC). Radon, thoron and thoron progeny concentrations vary from 31?±?1 to 436?±?12 Bq?m^–3, 4?±?7 to 246?±?5 Bq?m^–3, and 1.5?±?0.9 to 13.1?±?9.4 Bq?m^–3. The mean value of the equilibrium factor for thoron is estimated at 0.11?±?0.16. The annual effective dose due to exposure to indoor radon and progeny ranges from 0.6 to 9?mSv?a^–1 with an average value of 2.6?±?0.1?mSv?a^–1. The effective dose due to the exposure to thoron and progeny vary from 0.3 to 2.9?mSv?a^–1 with an average value of 1.0?±?0.4?mSv?a^–1. The contribution of thoron and its progeny to the total inhalation dose ranges from 7 to 60?% with an average value of 26?%; thus their contributions should not be neglected in the inhalation dose assessment.     

Comparison of active and passive radon survey in cave atmosphere,and estimation of the radon exposed dose equivalents and gamma absorbed dose rates

Radon (²²²Rn) measurements were conducted in the Pileki Cave with Radim 3A Active Radon Monitor equipment. Measurements were also done with the passive sampling method with CR-39 nuclear track detectors by exposing them for three months in the cave. Radon concentrations obtained from the active and passive sampling methods showed that, firstly, the concentrations inside the cave measured by the latter method differed greatly due to high humidity levels up to 88%. The total inside radon exposure dose equivalent people were subjected to was estimated to be 19?µSv a^?1 for visitors and 24,065?µSv a^?1 for guides. The gamma absorbed dose rates were determined for inside and outside the cave. The dose rates were calculated by means of using the ²²⁶Ra, ²³²Th and ⁴⁰K activity concentrations and by means of real-time measurements. The gamma absorbed dose rates were found to be much higher than the value of 55?nGy?h^?1 given by UNSCEAR. In addition, the mineralogical compositions and elemental analyses of samples taken from the cave were determined by XRD and WD-XRF methods.     

238U and total radioactivity in drinking waters in Van province,Turkey

As part of the national survey to evaluate natural radioactivity in the environment, concentration levels of total radioactivity and natural uranium have been analysed in drinking water samples. A survey to study natural radioactivity in drinking waters was carried out in the Van province, East Turkey. Twenty-three samples of drinking water were collected in the Van province and analysed for total α, total β and ²³⁸U activity. The total α and total β activities were counted by using the α/β counter of the multi-detector low background system (PIC MPC-9604), and the ²³⁸U concentrations were determined by inductively coupled plasma-mass spectrometry (Thermo Scientific Element 2). The samples were categorised according to origin: tap, spring or mineral supply. The activity concentrations for total α were found to range from 0.002 to 0.030 Bq L^?1 and for total β from 0.023 to 1.351 Bq L^?1. Uranium concentrations ranging from 0.562 to 14.710 μg L^?1 were observed in drinking waters. Following the World Health Organisation rules, all investigated waters can be used as drinking water.     

Conference and Research Reports

Groundwater discharge into an open pit lignite mining lake was investigated using radon-222 as a naturally occurring environmental tracer. The chosen study site was a meromictic lake, i.e., a water body that is divided horizontally into two separate layers – the upper mixolimnion (with seasonal mixing) and the lower monimolimnion (without seasonal mixing). For the estimation of groundwater discharge rates into the lake, a simple box model including all radon sinks and sources related to each layer was applied. Two field investigations were performed. During the October campaign, the total groundwater discharge into the lake was found to be 18.9 and 0.7 m³ d^?1 for the mixolimnion and monimolimnion, respectively. During the December campaign, the groundwater discharge into the mixolimnion was 15.0 m³ d^?1, whereas no discharge at all was observed into the monimolimnion. Based on the given water volumes, the residence time of lake water was 5.3 years for the monimolimnion and varies between 0.9 and 1.1 years for the mixolimnion. The investigation confirmed radon to be a useful environmental tracer for groundwater and surface water interactions in meromictic lake environments.     

Aerosol characterization and lung deposition of synthesized TiO2 nanoparticles for murine inhalation studies

This study presents a novel exposure protocol for synthesized nanoparticles (NPs). NPs were synthesized in gas phase by thermal decomposition of metal alkoxide vapors in a laminar flow reactor. The exposure protocol was used to estimate the deposition fraction of titanium dioxide (TiO₂) NPs to mice lung. The experiments were conducted at aerosol mass concentrations of 0.8, 7.2, 10.0, and 28.5 mg m^?3. The means of aerosol geometric mobility diameter and aerodynamic diameter were 80 and 124 nm, and the geometric standard deviations were 1.8 and 1.7, respectively. The effective density of the particles was approximately from 1.5 to 1.7 g cm^?3. Particle concentration varied from 4 × 10⁵ cm^?3 at mass concentrations of 0.8 mg m^?3 to 12 × 10⁶ cm^?3 at 28.5 mg m^?3. Particle phase structures were 74% of anatase and 26% of brookite with respective crystallite sized of 41 and 6 nm. The brookite crystallites were approximately 100 times the size of the anatase crystallites. The TiO₂ particles were porous and highly agglomerated, with a mean primary particle size of 21 nm. The specific surface area of TiO₂ powder was 61 m² g^?1. We defined mice respiratory minute volume (RMV) value during exposure to TiO₂ aerosol. Both TiO₂ particulate matter and gaseous by-products affected respiratory parameters. The RMV values were used to quantify the deposition fraction of TiO₂ matter by using two different methods. According to individual samples, the deposition fraction was 8% on an average, and when defined from aerosol mass concentration series, it was 7%. These results show that the exposure protocol can be used to study toxicological effects of synthesized NPs.