Dose estimation derived from the exposure to radon, thoron and their progeny in the indoor environment (original) (raw)
Related papers
Indoor radon/thoron levels and inhalation doses to some populations in Himachal Pradesh, India
Journal of Environmental Monitoring, 2002
It is well established that some areas of Himachal Pradesh (H.P.) state of India situated in the environs of the Himalayan mountains are relatively rich in uranium-bearing minerals. Some earlier studies by our group have indicated high levels of radon (w200 Bq m 23 ) in the dwellings. It is in this context that an indoor radon/thoron survey has been carried out in selected villages of four districts in the state of H.P. This survey has been conducted as a part of a national, coordinated project using twin chamber dosemeter cups designed by the Environmental Assessment Division (EAD), Department of Atomic Energy, Govt. of India. The track-etch technique is used for calibration of plastic detector LR-115 type-II which are employed for recording alpha tracks due to radon/thoron and their daughters. Year long radon/thoron data have been collected for seasonal correlations of indoor radon/thoron in the dwellings. The indoor radon levels have been found to vary from a minimum value of 17.4 Bq m 23 to a maximum value of 140.3 Bq m 23 . The indoor thoron levels vary from a minimum value of 5.2 Bq m 23 to a maximum value of 131.9 Bq m 23 . The year average dose rate for the local population varies from 0.03 mSv h 21 to 0.83 mSv h 21 . The annual exposure dose to inhabitants in all the dwellings lies below the upper limit of 10 mSv given in ICRP-65.
Environmental Earth Sciences, 2013
Radon, thoron, and their progeny are largest contributors to the radiation dose received by human beings present in the natural environment. The indoor radon depends upon many factors such as building materials, meteorology, ventilation, and occupant's behavior. This paper presents the measurements of indoor radon, thoron, and their progeny in four villages in rural area of district Kanshiram Nagar (Kasganj) in the state of Uttar Pradesh in Northern India. The concentration of indoor radon and thoron varies from 10.32 to 72.24 and 11.61 to 84.49 Bq m -3 with a geometric mean (GM) of 29.49 and 31.20 Bq m -3 , respectively. The concentration of radon and thoron daughters was found to vary from 1.11 to 7.80 and 0.31 to 2.28 mWL, respectively. The annual exposure due to radon and thoron mainly vary from 0.05 to 0.30 WLM. The preliminary results (i.e., bare mode exposure of the LR-115 detectors fixed on cards) of this study have been separately published and compared this recent data with those results.
Annual Inhalation Dose of Indoor Radon and Thoron in Mizoram, India
Crimson Publishers, 2021
The geographical location of the study area is Saiha and Lawngtlai districts of Mizoram, India within Latitude-22 0 29 ' 28.3 " to 22 0 36 ' 59.4 " and Longitude 92 0 59 ' 14.3 " to 92 0 52 ' 22.0 " with altitude ranging from 1866±10 feet to 3807±10 feet from the sea level. Methods Indoor radon & thoron The LR-115 type-II plastic track detectors (SSNTDs) kept in the Dosimeter was deployed
Radiation protection dosimetry, 2016
Long-term measurements of indoor radon, thoron and their progeny concentrations have been carried out in dwellings of Yamuna and Tons Valleys of Uttarkashi, Garhwal Himalaya to investigate the health risk associated with inhalation of radon, thoron and progeny. The experimentally determined values of radon, thoron and progeny concentrations were used to estimate the annual inhalation doses and annual effective doses. The annual inhalation dose has been found to vary from 0.8 to 3.9 mSv y(-1)with an average of 1.8 mSv y(-1) The annual effective dose from the exposure to radon and its progeny in the study area has been found to vary from 0.1 to 2.4 mSv with an average of 1.2±0.6 mSv. Similarly, the annual effective dose due to thoron and its progeny has been found to vary from 0.2 to 1.5 mSv with an average of 0.6±0.4. The measurement techniques and results obtained are discussed in detail.
2020
237-244Radioactive materials which occur naturally have widely presence in the earth’s crust and these materials are the most common sources of ionizing radiation present in an environment. Radon and its decay product contribute significant amount (more than 50%) of ionizing radiation in the atmosphere. This ionizing radiation increases the exposure of radiation to human being in the surroundings. The risk due to radon-222 and its decay products is more in poorly ventilated houses, mines and caves etc. This paper presents a review study on radon-222 and thoron-220 concentration/level done previously in the Garhwal region of Uttarakhand state. In this review paper, the various outcomes of indoor radon-222 and thoron-220 concentration measured in the Garhwal Himalaya region are mainly discussed in details
Radiation protection …, 2012
LR-115 (type II)-based radon-thoron discriminating twin-chamber dosemeters have been used for estimating radon ( 222 Rn) and thoron ( 220 Rn) concentrations in dwellings of south-western Punjab, India. The present study region has shown pronounced cases of cancer incidents in the public [Thakur, Rao, Rajwanshi, Parwana and Kumar (Epidemiological study of high cancer among rural agricultural community of Punjab in Northern India. Int J Environ Res Public Health 2008; 5(5):399-407) and Kumar et al. (Risk assessment for natural uranium in subsurface water of Punjab state, India. Hum Ecol Risk Assess 2011;17:381-93)]. Radon being a carcinogen has been monitored in some dwellings selected randomly in the study area. Results show that the values of radon ( 222 Rn) varied from 21 to 79 Bq m 23 , with a geometric mean of 45 Bq m 23 [geometric standard deviation (GSD 1.39)], and those of thoron ( 220 Rn) from minimum detection level to 58 Bq m 23 with a geometric mean of 19 Bq m 23 (GSD 1.88). Bare card data are used for computing the progeny concentration by deriving the equilibrium factor (F ) using a root finding method [Mayya, Eappen and Nambi (Methodology for mixed field inhalation dosimetry in monazite areas using a twin-cup dosemeter with three track detectors. Radiat Prot Dosim 1998;77(3):177-84)]. Inhalation doses have been calculated and compared using UNSCEAR equilibrium factors and by using the calculated F-values. The results show satisfactory comparison between the values.
Journal of Radioanalytical and Nuclear Chemistry, 2014
The radiation dose due to inhalation of radon, thoron and their progenies constitute a major part (50 %) of the total natural background dose received by a man. Thus measurement of indoor radon in dwellings is very important. In the present study, radon, thoron and their decay product measurements were carried out using passive detector systems, namely the pinholes dosimeters and Direct Radon (Thoron) progeny sensors. These measurements were carried out in indoor environments (different dwelling types) during January-April 2013 for 90 days, in the Gogi region. The timeaveraged mean radon, thoron and decay product concentrations were found to be within the permissible UNSCEAR limits.
The measurement of indoor radon, thoron and their daughter products was carried out in about fifty houses of dist. Shahjahanpur and Hardoi of Central Uttar Pradesh, India using LR-115 plastic track detectors. The measurements were made in residential houses from June 2008 to May 2009 hanging twin cup radon dosimeter at a height of 1.5-2m from ground level. The twin cup radon dosimeter can record the values of radon, thoron and their decay products separately. The graphs were plotted for radon concentration versus number of houses, thoron concentration versus number of houses and dose rate versus number of houses for different seasons. The resulting dose rates due to radon, thoron varied from 0.04 to 1.46 µSv/h. The observed radon and thoron concentration inside the houses of central Uttar Pradesh were found to be lower than the ICRP recommended value of 200 Bqm-3 and thus are within safe limits.
Measurement of indoor concentrations of radon and thoron in Mizoram, India
A A A ABSTRACT BSTRACT BSTRACT BSTRACT Radon, thoron and their progenies as a natural radiation hazards to human health is well known. These gases are present in the environment and their level of concentration depends upon geographical and geological conditions, meteorological factors, etc. The indoor radon/thoron concentration is also influenced by building materials, ventilating system and soil gas diffusion. Measurement of radon/thoron concentration in Mizoram is reported in this paper covering three districts, namely Aizawl, Kolasib and Champhai. In this study, we used solid-state nuclear track detectors to obtain the time integrated concentration levels of indoor radon/thoron. The study was conducted by measuring the cumulative exposure for a period of about 90 days each in 149 houses during rainy season (May-August). Houses were selected on the basis of geological characteristics of the area and the construction types in order to determine variation of concentrations of radon and thoron due to these factors. Among the three districts, Champhai District had the highest radon/thoron concentrations, while Kolasib District had the maximum thoron concentration. Among the different types of houses, concrete building had the average maximum concentration of radon followed by Assam type building with G.I. Sheet walls while the contribution due to asbestos walls of Assam type building was found to be lowest.