Radiation dose due to radon,thoron and their decay products in indoor environment of Khurja City,U.P., India

Inhalation of radon, thoron and their decay products can cause a significant health hazard when present in enhanced levels in the indoor environment like a human dwelling. In the present work a set of indoor radon and thoron measurements was carried out using time-integrated passive twin cup dosimeters containing LR-115 Type II solid state nuclear track detectors in different houses of Khurja City in Bulandshahar district of U.P. in India, built of the same type of building materials. The radon gas concentration was found to vary from 9.18 to 23.19 Bq m^?3 with an average value of 16.02 Bq m^?3 (SD = 3.68) and the thoron gas concentration varied from 2.78 to 9.03 Bq m^?3 with an average value of 5.36 Bq m^?3 (SD = 1.58). The radon progeny concentration ranged from 0.99 to 2.51 mWL with an average value of 1.77 mWL (SD = 0.40) and the concentration of thoron progeny was found to vary from 0.30 to 0.98 mWL with an average value of 0.58 mWL (SD = 0.17). The annual effective dose varied from 0.27 to 0.67 mSv year^?1 with an average value of 0.47 mSv year^?1(SD = 0.10).     

Study of radon,thoron and their progeny levels in indoor environment of Firozabad city in U.P., India

Twin cup pin-hole dosimeters having LR-115 as the detector were used to measure the concentration of radon and thoron in the dwellings of Firozabad city of Uttar Pradesh State in India. The mean values of radon, thoron, radon progeny and thoron progeny concentrations were found to be 37.4 Bqm^?3, 13.7 Bqm^?3, 4.0 and 1.5 mWL respectively. The average value of annual effective dose equivalent to the inhabitants of Firozabad city was found to be 1.1 mSv and is below the action level as recommended by the ICRP.     

Indoor radon measurement in Izmir Province,Turkey

In 2013, an extensive study was performed in a total of 117 locations in Izmir province and indoor radon levels were measured using the alpha track etch integrated method with LR-115 detectors. As the maps are more practical to interpret the results of radiological survey, the distributions of indoor ²²²Rn activities in four most densely populated districts of Izmir were mapped in detail. It is seen that the estimated average radon concentration level (210 Bq m^?3) determined in Izmir province was almost three times higher than the mean value for Turkey (81 Bq m^?3). Exposed annual effective dose equivalents for Izmir province were estimated in the range of 0.7 to 12.3 mSv year^?1 with a mean of 5.3 mSv year^?1. In this study, it is pointed out that indoor radon concentration was affected by the age of the building and height above the ground.     

Radon and thoron concentrations in offices and dwellings of the Gunma prefecture, Japan

Summary Aone year survey of indoor radon and thoron concentrations was carried out in offices and dwellings of the Gunma prefecture, Japan. A passive integrating radon and thoron discriminative monitor was used in the survey. The annual mean radon concentration was 22±14 Bq ^. m^-3, and ranged from 12 to 93 Bq ^. m^-3 among the 56 surveyed rooms. Radon concentration in offices was generally higher than that in the dwellings, with the arithmetic averages of 29 and 17 Bq ^. m^-3, respectively. Radon concentrations were generally lower in the traditional Japanese wooden houses than those houses built with other building materials. Seasonal variation of indoor radon was also observed in this survey. Compared to summer and autumn, radon concentrations were generally higher in spring and winter. The mean value of thoron to radon ratio was estimated to be 1.3, higher values were observed in the dwellings than in the offices. The annual effective dose from the exposure to indoor radon was estimated to be 0.47 mSv after taking the occupancy factors of offices and dwellings into account.     

Estimation of radon and thoron caused dose at exraction and processing sites of mineral sand mining area in Vietnam (HA TINH province)

Mineral sands are mined in several countries to supply to the titanium and zircon producing industries. Coastal black mineral sands usually contain, besides ilmenite (FeTiO₃) and rutile (TiO₂), radioactive minerals such as zircon (ZrSiO₄) and monazite (RePO₄). Radon and thoron activity concentration originated from natural radioactive contents of the black mineral sand was monitored at the extraction and processing for black minerals in the coastal areas of Ha Tinh Province, one of the around 40 coastal mineral sand deposits in Vietnam. The survey was carried out with the Raduet chambers made by Radosys Ltd—Hungary. The obtained results for 25 investigated points show that the measured values are not high in the residential houses and in case of the sand extraction site as well. At the titanium processing plant the measured values were higher than outside the facility (Radon: 18–55 Bq/m³ with average of 34 Bq/³ and Thoron 33–118 Bq/m³ with average of 58 Bq/m³) but still comparable to the average concentration of the world published by UNSCEAR. The typical outdoor levels of radon and thoron gas are each of the order of 10 Bq/m³. Although the radon concentrations were low in the zircon and titanium processing plants, the thoron concentrations in the houses for separating rutile and zircon were very high. At zircon processing factory, the thoron concentration could reach 2,931 Bq/m³ and the estimated annual effective dose would be 21.4 mSv/a. Intervention has to be taken in order to reduce the thoron level in this factory since the level of thoron and its progenies corresponding to an annual occupational effective dose is beyond the action level of 6 mSv/a.     

Calibration technique for a CR-39 detector for soil and water radon exhalation rate measurements

The calibration factor of 0.029 ± 0.0002 track cm^?2 per Bq d m^?3 for radon concentration measurements was determined using CR-39 and RAD7 detectors. The ²²²Rn concentration varied from 2,225 to 9,950 and 12 to 1,002 Bq m^?3 in soil and water, respectively. The highest radon exhalation and gamma dose rates were found in Acid and undifferentiated granitic rocks and Miscellaneous soils.     

Assessment of natural and fallout radioactivity in soil samples of Visakhapatnam

Environmental gamma radiation levels around the new Bhabha Atomic Research Centre site at Visakhapatnam have been assessed. Natural and anthropogenic radionuclide activity concentrations in soil samples collected were determined using high-resolution gamma spectroscopy. Average activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K were found to be 38, 38, 230 and 520 Bq kg^?1, respectively. No anthropogenic radionuclide except fallout ¹³⁷Cs having mean concentration range ≤ 0.2–2.2 Bq kg^?1 was detected in the soil samples. The observed values are compared with the values reported for different areas in India and other parts of the world. The annual total external gamma radiation dose to the members of public estimated using the above observations ranged from 0.13 to 0.38 mSv y^?1 with an average of 0.25 mSv y^?1.     

Assessment of radioactivity associated with a low ore grade open cast mine at Banduhurang, Jharkhand, India and estimation of occupational exposure to the miners

The study summarizes radiological characteristics of Banduhurang open cast mine which includes qualitative and quantitative behavior of ²²²Rn concentration, external gamma radiation level over the mine pit as well as in its adjoining environment, long-lived alpha (LLα) activity concentration associated with the respirable size of ore dust and assessment of dose to the mine workers in 2006–2008. The investigations reveal that geometric means (χ_g) of measured radon concentration were 36.39, 38.69, 26.64 and 24 Bq m^?3 with respective geometric standard deviations (σ_g) were 1.52, 1.55, 1.36 and 1.68 Bq m^?3 and χ_g of gamma absorbed dose rates were 0.54, 0.64, 0. 45 and 0.15 μGy h^?1 with respective σ_g were 1.63, 1.53, 1.52 and 1.72 μGy h^?1 over the mine pit, ore yard, waste yard and in the surrounding environment within a 10 km radius to the mine, respectively. The χ_g of LLα activity was observed to be 16 mBq m^?3 with σ_g of 1.9 mBq m^?3. The annual mean effective dose equivalent received by the member radiation workers of Banduhurang mine was estimated to 1.41 mSv y^?1, which is about 7% of the prescribed dose limits of 20 mSv y^?1.     

Radon concentration in well water from Namom district (Southern Thailand): a factor influencing cancer risk

The radon concentrations were determined in well water samples from Namom district, Southern Thailand, by using a RAD7 radon monitoring system. The measured values ranged from 0.1 to 483.0 Bq l^?1, while the average ±1σ across all measured samples was 32.0 ± 9.2 Bq l^?1. Regarding the health risks from radon in household drinking water, some settlements had radon concentration exceeding 100 Bq l^?1, an upper limit set by the European Union Directive EC2013/51/EURATOM. It is of concern that the results indicate health risks, especially to those consumers who directly use well water with high radon concentration.     

Evaluation of radon induced lung cancer risk in occupants of the old and new dwellings of the Dera Ismail Khan City,Pakistan

In order to carry out indoor radon measurement in new and old buildings of the Dera Ismail Khan city, CR-39 based radon detectors were installed in bed rooms and sitting rooms/TV lounges in 25 (each) old and new houses and were exposed to indoor radon for 90 days. After processing, mean weighted average indoor radon concentrations in old and new houses were found to be 275 ± 33 and 86 ± 18 Bq m^?3 whereas mean annual effective doses expected to be received by the occupants were 6.86 ± 0.79 and 2.1 ± 0.43 mSv year^?1, respectively. From the measured weighted average indoor radon concentration, excess relative risk factor was calculated using the risk model of BEIR VI for the age group of 35 and 55 years. Average excess lung cancer risk was found to be 1.63 ± 0.19 and 1.35 ± 0.16 and 0.5 ± 0.10 and 0.4 ± 0.08 for old and new houses, respectively.     

Potassium concentrations and annual effective dose of the customary food stuffs in Mexico

Measurement of radionuclides concentration in foodstuffs allows to assess the intake’s assimilated dose. This contributes at least one-eighth of the mean annual effective dose due to natural sources. Among the trace elements in foodstuff, potassium is one of the most important elements. It is a well-known essential element and it occurs all over the earth. Three of the most customary consumed foodstuffs in Mexico since pre-Hispanic time (by all social classes) are the following: bean, chili and corn meal (“tortillas”). They were analyzed by γ-spectrometry in order to determine ⁴⁰K activity concentration, the derived annual effective dose, and the K mass fraction (%). Results show that the mean activity concentration of ⁴⁰K, annual effective dose and K mass fraction (%) are as follow: 901 ± 90 Bq kg^?1, 37.2 ± 3.7 μSv a^?1 and 2.84 ± 0.27 % for chili; 510 ± 10 Bq kg^?1, 27.5 ± 0.5 μSv a^?1 and 1.60 ± 0.04 % for bean; and, 90 ± 30 Bq kg^?1, 58.1 ± 19.4 μSv a^?1 and 0.27 ± 0.089 % for corn meal, “masa”. The total effective dose intake from these typical foodstuffs is about 0.122 ± 15.6 mSv a^?1in Mexico’s urban zones.     

Seasonal and diurnal variations of radon/thoron exhalation rate in Kanto-loam area in Japan

Radon and thoron concentration in the outdoor environment are affected by the magnitude of the exhalation rate that can vary diurnally and seasonally. This paper presents measurement results of radon and thoron exhalation rates and gamma-ray dose rate in different season at same location points in Gunma Prefecture Japan. Exhalation rates were measured by the MSZ instrument which is based on the accumulation method. Three measurement points Katashina Village, Midori City and Takasaki City were selected for measurement. Soil water saturation and soil temperature were measured to investigate their relationship with exhalation rate. The diurnal variation of exhalation rate may be correlated with soil temperature but no clear relationship was found between them. The gamma-ray dose rate do not vary significantly at the same places even in different season. The average radon exhalation rates were 11 ± 2, 2 ± 1, 5 ± 3 and 11 ± 4 mBq m⁻² s⁻¹ for spring, summer, autumn and winter, respectively. Those for thoron were 1,100 ± 100, 120 ± 30, 250 ± 80 and 860 ± 140 mBq m⁻² s⁻¹. Thus there was a variation of radon and thoron exhalation rate with different seasons. The radon and thoron exhalation rates in the summer and autumn surveys are higher than those in the spring and winter surveys which were affected by rainfall. It indicates that water saturation is an influential factor for radon and thoron exhalation rates.     

Background radiation study in Coimbatore city,Tamilnadu

The activity concentration and absorbed gamma dose rates due to primordial radionuclides (²³⁸U, ²³²Th and ⁴⁰K) have been determined for the soil of Coimbatore city using NaI(Tl) gamma-ray spectrometer. The average activity concentrations of ²³²Th, ²³⁸U and ⁴⁰K in the soil samples have been found to be 31.4 Bq·kg⁻¹, 12.8 Bq·kg⁻¹ and 698.0 Bq·kg⁻¹, respectively, which give the total gamma dose rate contribution of 56.4 nGy·h⁻¹. Grab sampling technique has been used to determine the indoor radon (²²²Rn) and thoron (²²⁰Rn) progeny levels in different dwellings in the city. The concentrations of radon and thoron progenies range from 0.4 to 10.4 and from 0.7 to 12.7 mWL with a mean value of 1.4 mWL and 3.1 mWL, respectively. The annual effective dose due to radon and thoron progeny has been found to be 0.14 mSv·y⁻¹.     

137Cs, 40K, alkali–alkaline earth element and heavy metal concentrations in wild mushrooms from Turkey

In 2002, an extensive study was performed in forest sites of Izmir. This first study results led on the one hand, to quantify of ¹³⁷Cs and ⁴⁰K concentration in mushrooms collected in the Izmir region and to a first evaluation of dose in people due to the ingestion of radionuclide-contaminated mushrooms. The mushroom concentration values varied over a wide range from below detection limit to 401 ± 4 Bq kg^?1 (dry wt) for ¹³⁷Cs. The ⁴⁰K concentration values obtained for different species of mushrooms ranged from 588 ± 26 Bq kg^?1 to 2024 ± 63 Bq kg^?1 (dry wt). The annual effective dose values due to mushroom ingestion for ¹³⁷Cs are lower than the ICRP-2007’s reference level value of 1 mSv for “existing” exposure situation. Inductively coupled plasma-mass spectrometry was used to measure many alkali–alkaline earth elements and heavy metals in mushroom samples. The relationships among the concentrations of ¹³⁷Cs and the stable elements were presented and the occurrence of metals in mushrooms was evaluated.     

Natural radioactivity and its gamma dose rate in Mission (Texas) soils

The activity concentration of radionuclides in ²³⁸U, ²³²Th, and ⁴⁰K were determined in Mission (Texas) surface soils through gamma-ray spectrometry measurements using hyper pure germanium detector. Activity concentrations of ²³⁸U, ²³²Th, and ⁴⁰K were 13–32 Bq kg^?1 (mean value: 23 Bq kg^?1), 17–47 Bq kg^?1 (mean value: 31 Bq kg^?1), and 100–460 Bq kg^?1 (mean value: 300 Bq kg^?1) respectively. The absorbed gamma dose rate in air from these soils were found in the range of 23 to 56 nGy h^?1 with an average value of 42 nGy h^?1. The contribution to the absorbed gamma dose rate in air was observed as 26 % from ²³⁸U, 45 % from ²³²Th, and 29 % from ⁴⁰K. The outdoor annual effective dose equivalent varied between 28 and 69 μSv y^?1 with the mean value of 52 μSv y^?1.The evaluated data were compared with the data from different countries and also with the world mean value.     

Measurement of radon concentration in groundwater in the Ashanti region of Ghana

Radon in groundwater and their annual effective dose in the Ashanti region of Ghana have been determined using the continuous grab sampling technique and an AB-5 detector. Mean levels of radon were in the range of 0.51–46.16 Bq L^?1. Effective annual doses ranged from 0.18–16.16, 0.13–12.08 and 0.09–8.31 μSv y^?1 for infants, children and adults, respectively. These values are significantly lower than the reference level of 0.1 mSv y^?1 recommended by the WHO and United Nations Scientific Committee on the Effects of Atomic Radiation for members of the public.     

Natural radioactivity in sand samples collected along the bank of river Indus in the area spanning over Gilgit to Lowarian, Pakistan: assessment of its radiological hazards

Sand is extensively used in construction of buildings. The presence of natural radioactivity in it results in internal and external exposure to the general public. Therefore, it is desirable to determine the concentration of naturally occurring radio-nuclides, namely ²³²Th, ²²⁶Ra and ⁴⁰K in sand. In this regard, in continuation of our earlier studies, 42 sand samples were collected from fourteen different locations along the banks of river Indus from Gilgit to Lowarian in the northern part of Pakistan covering an area of ~500 km. In order to measure the specific activities in these samples, a P-type coaxial high purity germanium based gamma-ray spectrometer was used. Average values of the measured activities of ²²⁶Ra, ²³²Th and ⁴⁰K were found to be 45.6 ± 3, 74.73 ± 3 and 339.8 ± 3.6 Bq kg^?1, respectively which results in an average absorbed dose rate 83.54 nGy h^?1. From the measured activities, average radium equivalent activity was found to be 178.59 Bq kg^?1. External and internal hazard indices were also calculated and found to be 0.48 and 0.61, respectively. Average effective dose expected to be received due to the gamma rays was 0.26 mSv y^?1. Measured natural radioactivity, hazard indices and effective doses received by the population were found to be within the recommended limits.     

Measurement of activity concentration of primordial radionuclides in soil samples from Thirthahalli taluk and the assessment of resulting radiation dose

The activity concentration of primordial radionuclides ²²⁶Ra, ²³²Th, and ⁴⁰K in soil samples of Thirthahalli taluk were measured systematically by using a low background HPGe detector coupled to 16 K MCA. The measured activity concentration of ²²⁶Ra lies between 5.1?±?0.2 and 79.5?±?1.7 Bq kg^?1with an average activity of 25.99 Bq kg^?1, ²³²Th ranges from 5.1?±?0.3 to 95.3?±?2.2 Bq kg^?1with an average activity of 33.60 Bq kg^?1and that of ⁴⁰K varies from 18.3?±?1.5 to 833.4?±?17.5 Bq kg^?1with an average activity of 175.52 Bq kg^?1. Higher concentration of these radionuclides were found in the soil samples where the regional geology is granites. The consequential gamma dose and the corresponding radiation hazard was also estimated and is found to be within the permissible limits. The possible radiological impact on the public was also determined and these results are presented in this paper.     

Evaluation of radon concentration and heavy metals in drinking water and their health implications to the population of Quetta,Balochistan, Pakistan

ABSTRACT

The purpose of this study is to estimate the concentrations of radon and heavy metals in drinking water and assess their health implications to the population of Quetta, Pakistan. The concentration of radon and heavy metals was measured in drinking water collected from tube wells of different depths of the Quetta, Balochistan, Pakistan, using RAD7 detector and Atomic Absorption Spectrometer, respectively. The results show that the concentration of radon ranged from 3.56 ± 0.98 to 8.56 ± 1.32Bq/L with an average of 5.67 ± 1.34Bq/L. The average value of contribution of radon in water to indoor air was found 2.02 ± 0.47mBq/L. In addition to concentration of radon in drinking water, physiochemical parameters like pH and electrical conductivity (EC), and annual effective doses for different age groups were also estimated. Positive correlation of (R² = 0.8471) was observed between depth of well and concentration of radon, however no such relations were found among pH and EC with concentration of radon. Average values of annual effective doses due to intake of radon for age groups 0–1 years (infants), 2–16 years (Children) and ≥17 years (adults) were found (3.00 ± 0.71)×10^?2, (1.1 ± 0.26)×10^?2 and (1.45 ± 0.34)×10^?2 mSv/y, respectively. Average values of heavy metals concentrations were found 1.85 ± 0.64, 3.21 ± 0.75, 5.06 ± 1.19, and 2.47 ± 0.77 and 5.58 ± 1.23 µg/L for As, Cr, Ni, Cd and Pb, respectively. The values of radon concentration and heavy metals in drinking water were found below the USEPA permissible limits, Thus we conclude that, the investigated waters are safe.     

The use of carbon dioxide as the reaction cell gas for the separation of uranium and plutonium in quadrupole inductively coupled plasma mass spectrometry (ICP-MS) for nuclear forensic samples

²²⁶Ra, ²³⁸U, ²³²Th, and ⁴⁰K radionuclides have been determined using gamma-ray spectrometry in soil samples collected from urban areas in the southern governorates of Jordan and showed average concentrations of (39 ± 18), (45 ± 20), (23 ± 13), and (233 ± 128) Bq kg^?1, respectively. The corresponding radio-elemental concentrations in the existing geological features were obtained and examined for the relative depletion/enrichment processes and state of equilibrium in soils. Radium equivalent activity, hazard indices, and annual gonadal dose equivalent do not exceed the permissible limits. Absorbed dose rates in air outdoor and external effective dose showed average values of 44.0 nGy h^?1 and 54.4 μSv y^?1, respectively.