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The indoor 222Rn and 220Rn were measured by using deposition progeny sensors and single-entry pinhole dosimeter around Kolar Gold Fields of Karnataka state, India. The thirty different places were identified and fixed the dosimetry cups for the determination. The 222Rn and 220Rn concentrations of indoor environment range from 26.2 ± 1.3 to 138.4 ± 1.6 and 21.2 ± 0.8 to 133.3 ± 1.5 Bq/m3 with a mean value of 68.8 ± 1.6 and 61.8 ± 1.5 Bq/m3, respectively. The equivalent concentrations of 222Rn and 220Rn values vary from 0.9 ± 0.4 to 7.6 ± 1.1 and 6.8 ± 0.8 to 19.8 ± 1.8 Bq/m3 with a standard value of 4.3 ± 0.8 and 14.2 ± 1.3 Bq/m3, respectively. The values between the equilibrium factor between 222Rn, 220Rn, and their daughter were also calculated and found to be 0.23 and 0.07, respectively. The average annual intake of 222Rn, 220Rn, and their daughters' products is 2.28 mSv/y1, slightly below the global average of 2.4 mSv/y1 from all components. The data obtained compare average values in the world.

Measurement of indoor radon, thoron and their equilibrium equivalent concentrations in different dwellings around Kabini river basin, Karnataka State, India was carried out using SSNTD based pin-hole dosimeters during 2017–2018. Indoor concentrations of radon and thoron are varied from 18.9 to 156.8 Bq m− 3 and 13.1 to 110.0 Bq m− 3, respectively. The present study reveals that the annual effective dose received by the people of the study area is lesser than the recommended level 3–10 mSv y− 1 of the International Commission of Radiological Protection and is safe from the exposure of radon, thoron and their progenies.

Concentration of radon in ground and drinking water samples are collected from 36 locations around Kabini River basin, Karnataka State, India was measured using Emanometry Technique and it varied from 1.1 to 38.9 Bq.L−1 with geometrical mean of 8.5 Bq.L−1. The higher radon values are found at western side of the river, this is due to the local geology of the area and the upstream water consists of higher activity concentration of radon than that of downstream of the river. The total annual effective dose received by inhalation and ingestion of radon varied from 7.58 to 106.26 µSv.y−1 with geometrical mean of 25.37 µSv.y−1. The annual effective doses were within the safe limit of 0.1 µSv.y−1 as prescribed by World Health Organization (WHO). Out of the total population in the study area, nearly 70% use underground water, 20% use river water and others use surface water (river and lakes) for drinking.

Indoor radon, thoron and their progeny levels were measured in various types of dwellings during 2016-17 in Hemavathi river basin, Karnataka by using solid state nuclear track detector based pin-hole dosemeters; dwellings of various types were chosen for the measurement. The dosemeters containing the detector (LR-115, Type II Film) was used for this purpose. The concentration of indoor radon in the study area varied from 30.72 to 196.08 Bq m-3 with a median of 83.13 Bq m-3 and thoron concentration varied from 15.56 to 227.78 Bq m-3. Higher concentrations of radon and its progeny were observed in granite flooring and cement roofing dwellings compared to other types of dwellings. The reason for higher concentration of indoor radon and its progeny is due to activity of radium present in granite and provision of less ventilation in dwellings. The equilibrium equivalent radon, thoron concentrations and annual effective dose are discussed.

The activity concentration and total annual effective dose of the terrestrial naturally occurring radionuclides (232Th, 226Ra and 40K) were measured in soil and rock samples collected from various locations of Hemavathi river basin in Karnataka, using HPGe detector. The results revealed that activity concentration of radionuclides 226Ra, 232Th and 40K in the soil had geometrical mean values of 16.7 ± 0.6, 33.9 ± 1.2 and 359.9 ± 9.2 Bq kg−1, respectively. In rock samples activity concentrations of 226Ra, 232Th and 40K had geometrical mean values of 20.2 ± 0.7, 18.0 ± 0.9 and 276 ± 9.6 Bq kg−1, respectively. The external Hazard index and indoor hazard index were found to be within safety limits prescribed by European commission 1999 report.

The study on natural radioactivity level in the soil plays a significant role in health physics. The present study has been carried out with the aim of estimating activity concentration of radionuclides in soil samples collected at 30 places around Kolar Gold Fields, Kolar district using gamma ray spectrometry. Average values of activity concentration of 226Ra, 232Th and 40K in soil samples of the present study are 27.3 ± 1.8, 63.1 ± 2.5 and 818 ± 6 Bq kg−1, respectively. The average radium equivalent activity (Raeq), absorbed dose rate and annual effective dose have been calculated and compared with the referred safe values.

Concentration of radon and physicochemical parameters present in ground water collected from 65 bore wells of 30 different locations around Kolar Gold Fields, Kolar District, India are estimated by emanometry technique and chemical analysis. Activity of radium present in rock samples of the study area using HPGe detector are presented and discussed in the manuscript. The average radon concentration in the collected water samples are ranged from 3.3 ± 0.8 to 122.9 ± 2.1 Bq l−1 with an average value of 46.9 ± 1.7 Bq l−1. Average value of activity concentration of radium is found to be 29.1 Bq kg−1.

Concentrations of radon in drinking water collected from 32 locations of Hemavathi river basin, Karnataka, India have been measured by emanometry method. The radon concentration in water ranged from 2.7 ± 0.1 to 138.5 ± 1.5 Bq l−1 with a geometrical mean of 25.3 ± 1.1 Bq l−1. The study revealed that about 82.35% of drinking water samples contained radon concentration more than 11.1 Bq l−1, the limit is fixed by Environmental Protection Agency. Among the different parameters measured, concentration of radon showed weak correlation with chloride and no correlation with alkalinity, pH, nitrate, sulphate, fluoride and total dissolved substance.

Single crystals of ternary mixed alkali halide crystals (KCl) 0.9-x (KBr) x (NaI) 0.1 of different compositions with Lithium Sulphate doping were grown by melt Technique using AR grade chemicals as starting materials.. All the crystals were grown under identical conditions. Ternary crystals cleaved from the grown bulk samples were used for the present investigation.

Concentrations of radon, thoron and their progeny inside the working place depend on the activity of radionuclides in the soil, building materials, atmospheric conditions, construction of the building, type of work and ventilation condition. Radon is a radioactive noble gas, and it is emanated from 226Ra present in earth crest and building material. Based on the type of work, construction of the building and ventilation condition, concentrations of radon, thoron and their progeny have been measured in 60 workplaces at 10 locations of Mysuru, Bengaluru and Kolar districts of Karnataka state using Solid-State Nuclear Track Detector technique. From the study, variations of radon, thoron and their progeny have been observed with the nature of work.

Radon activity concentration in soil gas has been studied in and around Bharathinagara, Mandya district (12° 13|| N and 77° 20|| E) using Solid State Nuclear Track Detectors with Twin cup dosimeter. The activity concentration of 222Rn in soil gas was studied at two depths. Radon in soil gas was found to increase with depth and decrease with increase in moisture content of the soil. Radon in soil gas was found to be higher in winter season which varies from 0.22 ± 0.01 to 1.31 ± 0.01 kBq/m3 with a Geometric mean value of 0.56 ± 0.01 kBq/m3 in 1 m depth and lower radon soil gas was found to be 0.16 ± 0.01 to 0.60 ± 0.01 kBq/m3 with a Geometric mean value of 0.30 ± 0.01 kBq/m3 in 0.5 m depth during summer season. The activity concentrations of radon soil gas from in and around Bharathinagara are lower compared to those in other parts of the world.

An extensive studies on the indoor activity concentrations of thoron, radon and their progeny in the granite region in the state of Karnataka, India, has been carried out since, 2007 in the scope of a lung cancer epidemiological study using solid-state nuclear track detector-based double-chamber dosemeters (LR-115, type II plastic track detector). Seventy-four dwellings of different types were selected for the measurement. The dosemeters containing SSNTD detectors were fixed 2 m above the floor. After an exposure time of 3 months (90 d), films were etched to reveal tracks. From the track density, the concentrations of radon and thoron were evaluated. The value of the indoor concentration of thoron and radon in the study area varies from 16 to 170 Bq m(-3) and 18 to 300 Bq m(-3) with medians of 66 and 82.3 Bq m(-3), respectively, and that of their progeny varies from 1.8 to 24 mWL with a median of 3.6 mWL and 1.6 to 19.6 mWL, respectively. The concentrations of indoor thoron, radon and their progeny and their equivalent effective doses are discussed.

The radon survey was performed in granite quarries around Bangalore rural district and Bangalore city as part of a lung cancer epidemiological study. Long duration measurements of indoor and outdoor radon, thoron and their progenies concentrations were made around granite quarries of Bangalore rural district by using Solid State Nuclear Track Detector (SSNTD, LR-115, Type-II Plastic track detector) during summer and winter period (2006–07). The increase of radioactivity in granite quarries and inhalation dose to workers and populations near the quarries have been summarized. The higher concentrations of radon and thoron in granite quarries suggest radiation health effects on workers and public around the quarries is higher than permissible levels. The results are presented and analyzed with reference to ICRP limits.

Studies on natural radiation levels and radionuclides were carried out extensively in the environment of granite quarries of Kanakapura, Ramanagara Taluks and Bidadi Hobli in Bangalore rural District and Bangalore city. The indoor and outdoor gamma exposure rate in air was measured using an environmental dosemeter, and it is converted into absorbed dose using suitable conversion factor. The activity concentrations of natural radionuclides in rock samples and also in soil samples were measured using an HPGe gamma-ray spectrometer. The results reveal that the activity concentrations of (226)Ra, (232)Th and (40)K in rocks are found to be vary from 32.2 to 163.6, 128.3 to 548.6 and 757.4 to 1418.4 Bq kg(-1), respectively, with corresponding arithmetic mean values of 93.2, 306.2 and 1074.4 Bq kg(-1). Activity concentrations of (226)Ra, (232)Th and (40)K in soil samples were found to vary from 32.4 to 55.2, 39.9 to 214.3 and 485.4 to 1150.2 Bq kg(-1), respectively, with corresponding arithmetic mean values of 40.7, 93.1 and 750.4 Bq kg(-1). The average activity levels of all these radionuclides are above the global average. This is consistent with the geological and geo-chemical significance of the rocks of the area under investigation. The results of these systematic investigations are discussed in detail and compared with the literature values represented for other environments.

Indoor radon and its progeny levels were measured during 2005-06 in Bangalore rural district and in Bangalore City by using Solid State Nuclear Track Detector (SSNTD)-based twin cup dosemeters, and the activity of radium present in soils and rocks was measured by using HPGe detector. Fifty dwellings of different types were chosen for the measurement. The dosimeters containing the detector (LR-115 Type II Film) used in each house were fixed 2 m above the floor. After an exposure time of 90 days, films were etched to reveal tracks. From the track density, the concentrations of radon were evaluated. The value of radon concentration in the indoor air near granite quarries varies from 55 to 300 Bq.m(-3) with a median of 155 Bq.m(-3) and its progeny varies from 0.24 to 19.6 mWL with a median of 8.4 mWL. In Bangalore City, the concentration of radon varies from 18.4 to 110 Bq.m(-3) with a median of 45 Bq.m(-3) and its progeny varies from 1.62 to 11.24 mWL with a median of 4.15 mWL. Higher concentrations of radon and its progeny were observed in granite quarries compared with Bangalore City. The main reason for the higher indoor radon and its progeny concentration is due to the mining activity and the types of the bedrock. The concentration of radon mainly depends on the activity of radium present in soils and rocks and the types of building materials used. The activity of radium varies in granitic regions of Bangalore rural district from 42.0 to 163.6 Bq.kg(-1) with a median of 112.8 Bq.kg(-1). The concentrations of indoor radon and its daughter products and equivalent effective dose are discussed.

The present study deals with the activity concentration of natural primordial radionuclides, namely 226Ra, 232Th, and 40K in different rock samples of Ramanagara and Tumkur districts, and has been studied by using gamma ray spectrometry. The average activity concentration of 226Ra, 232Th, and 40K in the collected rock samples was found to be 41.08 ± 2.12, 86.26 ± 2.94, and 869.29 ± 3.78 Bq.kg−1, respectively. The average radium equivalent activity (Raeq) was found as 225.29 Bq.kg−1 and these values are well within the recommended limit prescribed for dwellings as 370 Bq.kg−1. The external (H ex) and internal hazard index (H in) values are also less than unity. The mean value of absorbed dose rate in rock samples was found as 107.33 nGy.h−1, respectively, and is slightly higher than the worldwide average value. The average indoor and outdoor annual effective dose values for rock samples are 0.526 mSv.y−1 and 0.131 mSv.y−1, respectively. These values are lower than the average world recommended value of 1 mSv.y−1.

Radon is a radioactive gas produced by the decay of 226 Ra present in the soil, rock, water and in atmosphere. Radon, thoron and their progeny are present in indoor and outdoor atmosphere. The concentration of these gases in indoor atmosphere is higher than that of outdoor. In the present study, the concentrations of radon, thoron and their progenies in some taluks of Tumkur district were estimated and the doses due them were calculated. Twin cup dosimeters with alpha sensitive films, LR- 115 type-2, were used for the measurement of concentrations of radionuclides. The mean indoor gamma radiation dose was found to be 0.64 mSvy −1 with highest of 0.75 mSvy −1 in Kunigal taluk. The concentrations of radon in good ventilated dwellings with granite floorings varied from 20.66 Bqm −3 in Tumkur city to 27.61 Bqm −3 in Kunigal. In poor ventilated dwellings, the concentrations of radon varied from 35.56 Bqm −3 in Tumkur to 44.87 Bqm −3 in Turuvekere. The dwellings with granite flooring showed higher concentration of radioactive gases than with marble as flooring and other floorings. The dwelling situated near the granite rocks showed higher concentrations.