Bikramjit Singh Bajwa

Comparative study of natural radioactivity levels in soil samples from the Upper Siwaliks and Punjab, India using gamma-ray spectrometry

Natural radioactive materials under certain conditions can reach hazardous radiological levels. So, it becomes necessary to study the natural radioactivity levels in soil to assess the dose for the population in order to know the health risks and to have a baseline for future changes in the environmental radioactivity due to human activities. The natural radionuclide (226Ra, 232Th, and 40K) contents in soil were determined for 26 locations around the Upper Siwaliks of Kala Amb, Nahan and Morni Hills, Northern India, using high-resolution gamma-ray spectrometric analysis. It was observed that the concentration of natural radionuclides viz., 226Ra, 232Th and 40K, in the soil varies from 28.3+/-0.5 to 81.0+/-1.7Bqkg(-1), 61.2+/-1.3 to 140.3+/-2.6Bqkg(-1) and 363.4+/-4.9 to 1002.2+/-11.2Bqkg(-1) respectively. The total absorbed dose rate calculated from activity concentration of 226Ra, 232Th and 40K ranged from 71.1 to 162.0nGyh(-1). The radium equivalent (Req) and the external hazard index (Hex), which resulted from the natural radionuclides in soil, were also calculated and found to vary from 149.4 to 351.8Bqkg(-1)and from 0.40 to 0.95 respectively. These values in Upper Siwaliks area were compared with that from the adjoining areas of Punjab. The radium equivalent activities in all the soil samples were lower than the limit (370Bqkg(-1)) set in the Organization for Economic Cooperation and Development (OECD) report and the dose equivalent was within the safe limit of 1mSvy(-1).

Earthquake precursory studies in Kangra valley of North West Himalayas, India, with special emphasis on radon emission.

The continuous soil gas radon monitoring is carried out at Palampur and the daily monitoring of radon concentration in water is carried out at Dharamshala region of Kangra valley of North West Himalayas, India, a seismic zone V, to study the correlation of radon anomalies in relation to seismic activities. In this study, radon monitoring in soil was carried out by using barasol probe manufactured by Algade France, whereas the radon content in water was recorded using RAD 7 radon monitoring system of Durridge Company USA. The effect of meteorological parameters viz. temperature, pressure, wind velocity, rainfall, and humidity on radon emission has been studied. The seasonal average value and standard deviation of radon in soil and water is calculated to find the radon anomaly to minimize the effect of meteorological parameters on radon emission. The radon anomalies observed in the region have been correlated with the seismic events of M>or=2 reported by Wadia Institute of Himalayas Geology Dehradoon and Indian Meteorological Department, New Delhi in NW Himalayas within 250km distance from the monitoring stations.

Uranium and other heavy toxic elements distribution in the drinking water samples of SW-Punjab, India

Abstract In the present investigations, Laser Fluorimetry technique has been used for the microanalysis of uranium content in drinking water samples collected from different sources like the hand pumps, tube wells of various depths from wide range of locations in the four districts of SW-Punjab, India. The purpose of this study was to investigate the uranium concentration levels of ground water being used for drinking purposes and to determine its health effects, if any, to the local population of this region. Corresponding radiological and chemical risks have also been calculated for the uranium concentrations in ground water samples. Some other heavy elements have also been analysed using the Atomic Absorption Spectrometry. In this region, uranium concentration in 498 drinking water samples has been found to vary between 0.5–579 μgl−1with an average of 73.5 μgl−1. Data analysis revealed that 338 of 498 samples had uranium concentration higher than recommended safe limit of 30 μgl−1 (WHO, 2011) while 216 samples exceeded the threshold of 60 μgl−1 recommended by AERB, DAE, India, 2004.

Relationships between radon anomalies and seismic parameters in N-W Himalaya, India

Abstract Radon data accumulated during 1992–1999 in the grid (30–34°N, 74–78°E) in N-W Himalaya have been anlaysed vis a vis seismic data recorded in the same area, supplied by Indian Meteorological Department (IMD) network. In general, there is a positive correlation between the total radon emission and the microseismicity in the area under investigation. The earthquake magnitude has moderate positive correlation with epicentral distance and low positive correlation with amplitude of radon precursory signal, whereas both show low negative correlation between them. Empirical scaling relations are proposed using the best fit straight line from the log-linear graphs between magnitude of the events and log of the product of amplitude of radon anomaly and epicentral distance. The error between the recorded and calculated magnitude is also taken into account. The error range is higher at lower epicentral distances and magnitudes, showing that the local geology and tectonics have predominant influence on radon signals.

A study of indoor radon, thoron and their progeny measurement in Tosham region Haryana, India

Abstract In the present study indoor radon, thoron and their decay products concentrations have been measured using the newly developed LR-115 type-ІІ based Radon-Thoron discriminating twin-cup dosimeters with single entry face, direct radon and thoron progeny sensors (DRPS/DTPS) respectively. The annual annihilation dose has been assessed from measured radionuclide concentration to find out major contributor of lung cancer in the study area. The measurements have been carried out in NINETY dwellings of THIRTEEN different villages situated in and around the Tosham region. This region is known to be composed of acidic volcanic and associated granites. Dwellings were selected mainly targeting different type building material used in construction of houses like concrete–brick, mud-brick, and mud-thatches along with an idea of different ventilation conditions which affects the equilibrium factor (EF). The EF in this region has been varying from 0.20 to 0.72 and 0.03–0.13 for indoor radon and thoron respectively. The average inhalation dose observed in dwellings of different villages varies from 1.33 ± 0.31–3.36 ± 0.72 mSv/y that lies within the safe limits recommended by ICRP (2011).

Radon, helium and uranium survey in some thermal springs located in NW Himalayas, India: mobilization by tectonic features or by geochemical barriers?

Radon, helium and uranium measurements have been carried out in hot water springs in the Parbati and Beas valleys of Himachal Himalaya. Most of these hot springs are known as famous pilgrimage centers. The activity of dissolved radon in the liquid phase is found to vary widely, by an order of magnitude, between 10 and 750 Bq L(-1), whereas, the dissolved helium content in these thermal springs varies between 10 and 100 ppm. The uranium contents are low and vary from <0.01 to 5 microg L(-1). The measured values of radon, helium and uranium are possibly controlled by structural geology, namely the presence of pervious fault systems, and by the lithology of the leached host rocks. Redox-potential geochemical barriers cause the mobilization of uranile ions in solution (UO2+); the most plausible hypothesis is when the conditions are oxidising, confirming the importance of physico-chemical conditions up to the supergenic environment, to control the fluid geochemistry of the U-He-222Rn system. Some evidence is available from both geothermometric considerations and geochemical data which will be reported elsewhere, whereas the present study is focused on U decay series-noble gas geochemistry. The first analysis of collected 3He/4He data is consistent with a crustal signature at the studied thermal springs.

Radon monitoring in groundwater of some areas of Himachal Pradesh and Punjab states, India

Radon measurements have been carried out in groundwater of Himachal Pradesh and Punjab states, India. Radon concentration values in potable water show a wide range of variation from source to source and from place to place. Generally, radon concentration values in thermal springs groundwater have been found to be higher than the values from other sources.

Measurement of soil gas radon and its correlation with indoor radon around some areas of Upper Siwaliks, India.

Radon is a radioactive gas which makes the primary contribution to the natural radiation to which people are exposed. For that reason, great importance is attributed to the determination of radon concentration levels in water, indoor air and soil gas and outdoors. In this paper, measurements of radon concentration in soil gas have been carried out around some areas of the Upper Siwaliks of the Kala Amb, Nahan and Morni Hills, India, using a portable AlphaGUARD PQ 2000 device into which the soil gas is drawn using active pumping. The soil gas radon concentration around the Upper Siwaliks was found to vary from 11.5 +/- 0.9 to 78.47 +/- 3.1 kBq m(-3). The annual average indoor radon concentration in the study area was measured in the range from 71.7 +/- 21.0 to 421.7 +/- 33.6 Bq m( - 3) using LR-115 type II cellulose nitrate films in the bare mode. The values of soil gas radon concentration in the study area were compared with those from the adjoining low-radioactive areas of Punjab. Since the soil or bedrock beneath a building is one of the sources of radon gas in the indoor air, an effort has been made to find a possible correlation between soil gas radon with the indoor radon. A satisfactory positive correlation has been observed between soil gas radon and indoor radon in the study area.

A comparative study of indoor radon level measurements in the dwellings of Punjab and Himachal Pradesh, India

Abstract The LR-115 type-II plastic track detector has been used for measuring the indoor radon levels in the dwellings of some villages of Punjab and Himachal Pradesh. In Punjab, the villages surveyed are Rampura Phul, Lehra Mahabat and Pitho (villages in Bathinda district), and Amritsar city. The average indoor radon levels in these areas are found to vary from 64 to 152 Bq/m 3 , which are quite within the safe limits recommended by International Commission on Radiological Protection (Ann. ICRP 23(2)). The indoor radon levels have also been measured in the dwellings of Hamirpur district of Himachal Pradesh. The villages surveyed in this area are Nukhel, Badarn, Galore-Khas, Har-Upper, Tikker Brahamana and Awah-Lower where radon concentration has been found to vary from 261 to 724 Bq/m 3 . These values are higher than the recommended limit.

Measurements of Natural Radioactivity in Some Water and Soil Samples of Punjab State, India:

In the present investigation a nuclear track-etch technique using Solid State Nuclear Track Detectors was used to estimate the trace uranium concentration in water and soil samples collected from different sources and locations of the Amritsar and Bathinda cities of Punjab. The uranium concentration in the water samples collected from Amritsar was found to vary from 3.17 to 4.19 mg L 1 and in the Bathinda city it varied between 4.28 and 16.48 mg L 1. A lake sample, collected from the NFL water works site in Bathinda city had a uranium content of only 1.21 mg L 1 which was several times lower than those samples collected from hand-pumps and tube - wells from this area. The uranium concentration in soil samples of Amritsar city was found to vary from 0.61 to 1.27 ppm. In addition, soil samples from other cities of the Punjab were analysed using the Gamma-spectroscopic technique to determine 226Ra, 232Th and 40K concentrations in soil. The average values of the concentration of 1 respectively.