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A pilot survey in the Central Garhwal Himalayan region, India, assessed radon and thoron inhalation doses using RADUET, CR39 detectors during January to October 2013. Detectors were deployed for 95, 101, and 92 days in winter, summer, and in the rainy season respectively. Highest 222Rn concentration (260 ± 13 Bqm−3) was in cemented categories, followed by 170 ± 8 and 190 ± 10 Bqm−3 in wood-stone dwellings. Wood-mud categories had lower levels (116 ± 6 to 128 ± 8 Bqm−3). Despite significant 222Rn concentration, analysis of seasonal radiation exposures (EECTn and Feq) with short-lived decay products showed reduced doses in winter months ranging from 2.97 (± 0.31) to 6.91 (± 0.32) Bqm−3. [ABSTRACT FROM AUTHOR]

Exposure to radon, 222Rn, is assumed to be the most significant source of natural radiation to human beings in most cases. It is thought that radon and its progeny are major factors that cause cancer. The presence of thoron, 220Rn, was often neglected because it was considered that the quantity of thoron in the environment is less than that of radon. However, recent studies have shown that a high thoron concentration was found in some regions and the exposure to 220Rn and its progeny can equal or several time exceed that of 220Rn and its progeny. The results of thoron and its progeny measurements in the houses of high background radiation area (HBRA) of the southeastern coast of Odisha, India presented here. This area is one of the high background radiation areas in India with a large deposit of monazite sand which is the probable source of thoron. Both active and passive methods were employed for the measurement of thoron and its progeny in cement, brick and mud houses in the study area. Thoron concentration was measured using RAD-7 and Raduet. A CR-39 track detector was employed for the measurement of environmental thoron progeny, both in active and passive modes. Thoron and its progeny concentrations were found to be comparatively high in the area. A comparison between the results obtained with various techniques is presented in this paper. [ABSTRACT FROM AUTHOR]

Terrestrial gamma radiation is one of the important radiation exposures on the earth's surface that results from the three primordial radionuclides 226Ra, 232Th and 40K. The elemental concentration of these elements in the earth's crust could result in the anomalous variation of the terrestrial gamma radiation in the environment. The geology of the local area plays an important role in distribution of these radioactive elements. Environmental terrestrial gamma radiation dose rates were measured around the eastern coastal area of Odisha with the objective of establishing baseline data on the background radiation level. The values of the terrestrial gamma radiation dose rate vary significantly at different locations in the study area. The values of the terrestrial gamma dose rate ranged from 77 to 1651 nGy h−1, with an average of 230 nGy h−1. During the measurement of the terrestrial gamma dose rate, sand and soil samples were also collected for the assessment of natural radionuclides. The activities of 226Ra, 232Th and 40K from these samples were measured using a gamma-ray spectrometry with a NaI(Tl) detector. Activity concentrations of 226Ra, 232Th and 40K ranged from 15.6 to 69 Bq kg−1 with an average of 46.7 Bq kg−1, from 28.9 to 973 Bq kg−1 with an average of 250 Bq kg−1 and from 139 to 952 Bq kg−1 with an average of 429, respectively. The detailed significance of these studies has been discussed from the radiation protection point of view. [ABSTRACT FROM AUTHOR]

This paper presents the preliminary results of radon and thoron measurements in the houses of Chhatrapur area of southeastern coast of Orissa, India. This area is one of the high radiation background radiation areas in India, which consists of monazite sand as the source of thoron. Both active and passive methods were employed for the measurements. Radon and thoron concentrations were measured in the houses of Chhatrapur area using twin cup radon dosemeters, RAD7 and radon–thoron discriminative detector (Raduet). Thoron progeny concentration was also measured in the houses using deposition rate measurements. Radon and thoron concentrations in the houses of study area were found to vary from 8 to 47 Bq m−3 and the below detection level to 77 Bq m−3, respectively. While thoron progeny concentration in these houses ranges between 0.17 and 4.24 Bq m−3, preliminary investigation shows that the thoron concentration is higher than radon concentration in the houses of the study area. The thoron progeny concentration was found to be comparatively higher, which forms a base for further study in the area. The comparison between the results of various techniques is presented in this paper. [ABSTRACT FROM PUBLISHER]

A car-borne survey was carried out in Kerala, India to estimate external dose. Measurements were made with a 3-in × 3-in NaI(Tl) scintillation spectrometer from September 23 to 27, 2013. The routes were selected from 12 Panchayats in Karunagappally Taluk which were classified into high level, mid-level and low level high background radiation (HBR) areas. A heterogeneous distribution of air kerma rates was seen in the dose rate distribution map. The maximum air kerma rate, 2.1 μGy/h, was observed on a beach sand surface. 232Th activity concentration for the beach sand was higher than that for soil and grass surfaces, and the range of activity concentration was estimated to be 0.7-2.3 kBq/kg. The contribution of 232Th to air kerma rate was over 70% at the measurement points with values larger than 0.34 μGy/h. The maximum value of the annual effective dose in Karunagappally Taluk was observed around coastal areas, and it was estimated to be 13 mSv/y. More than 30% of all the annual effective doses obtained in this survey exceeded 1 mSv/y.

Several industrial processes are known to enrich naturally occurring radioactive materials (NORM). To assess such processes with respect to their radiological relevance, characteristic parameters describing this enrichment will lead to interesting information useful to UNSCEAR. In case of mineral treatment plants, the high temperatures used in smelting and refining processes lead to high concentrations of (238)U and (232)Th. Also due to thermal power combustion, concentration of U and Th in the fly ash increases manifold. NORM samples were collected from a Thailand mineral treatment plant and Philippine coal-fired thermal power plants for investigation. Some studies are initiated from a high background radiation area near Gopalpur of Orissa state in India. These NORM samples were analysed by gamma-ray spectrometry as well as inductively coupled plasma mass spectrometry. The radioactivity in case of Orissa soil samples is found to be mainly contributed from thorium. This study attempts to evaluate levels of thorium activity in NORM samples.