Levels of thoron and progeny in high background radiation area of southeastern coast of Odisha, India

Abstract

Exposure to radon, (222)Rn, 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, (220)Rn, 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 (220)Rn and its progeny can equal or several time exceed that of (220)Rn 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.

Long-term measurements of residential radon, thoron, and thoron progeny concentrations around the Chhatrapur placer deposit, a high background radiation area in Odisha, India

“…The thickness of the films was adjusted to absorb the energy of alpha particles from radon, thoron and their progenies except for 212 Po (8.78 MeV). Since the Raduet and thoron progeny deposition detector are inexpensive and easy to use, they are often used in a large-scale survey (e.g., Chen et al, 2012;Janik et al, 2013;Kudo et al, 2015;McLaughlin et al, 2011;Ramola et al, 2010Ramola et al, , 2012.…”

“…In this area, surveys on radon and thoron concentrations in dwellings were carried out and they revealed that thoron concentration is higher than radon concentration (e.g., Ramola et al, 2010Ramola et al, , 2012Sulekha Rao and Sengupta, 2010). Sulekha Rao and Sengupta (2010) also attempted to calculate the dose due to inhalation of thoron (including its progeny) based on measurements of thoron gas.…”

Dose estimation derived from the exposure to radon, thoron and their progeny in the indoor environment

“…Although radiological importance of radon and its progeny has been acknowledged a long time ago, thoron had often been neglected due to its short half-life. The contribution of thoron to radiation doses has recently been recognized 6 7 8 9 . Many studies found that thoron can be a significant contributor to the radiation dose in residential buildings in some Asian, European and American countries 7 10 11 12 .…”

Distribution of natural radionuclide along Main Central Thrust in Garhwal Himalaya

“…This is known as emanation process and the total amount of radon emitted by pore space to environment is called the exhalation. The fraction of radon emanation and its exhalation rate depend on the geology of the area, soil porosity, structures (shears, faults and thrusts) and associated uranium mineralization (Choubey & Ramola, 1997;Duenas & Fernandez, 1987;Holkko & Liukkonen, 1993;Hubbard & Hagberg, 1996;Hubbard, Hagberg, & Enflo, 1992;Markkanen & Arvela, 1992;Prasad, Prasad, Gusain, Choubey, & Ramola, 2008;Ramola & Choubey, 2003;Ramola et al, 2012;Ramola, Singh, & Virk, 1988). Radon emanation rate is highest when soil moisture is between 15 and 20% in weight (Damkjaer & Korsbeck, 1985;Lindmark & Rosen, 1985;Stranden, Kolstad, & Lind, 1984).…”