Inhalation Dose and Source Term Studies in a Tribal Area of Wayanad, Kerala, India

Abstract

Among radiation exposure pathways to human beings, inhalation dose is the most prominent one. Radon, thoron, and their progeny contribute more than 50 per cent to the annual effective dose due to natural radioactivity. South west coast of India is classified as a High Natural Background Radioactivity Area and large scale data on natural radioactivity and dosimetry are available from these coastal regions including the Neendakara-Chavara belt in the south of Kerala. However, similar studies and reports from the northern part of Kerala are scarce. The present study involves the data collection and analysis of radon, thoron, and progeny concentration in the Wayanad district of Kerala. The radon concentration was found to be within a range of 12–378 Bq/m3. The thoron concentration varied from 15 to 621 Bq/m3. Progeny concentration of radon and thoron and the diurnal variation of radon were also studied. In order to assess source term, wall and floor exhalation studies have been done for the houses showing elevated concentration of radon and thoron. The average values of radon, thoron, and their progeny are found to be above the Indian average as well as the average values reported from the High Natural Background Radioactivity Areas of Kerala. Exhalation studies of the soil samples collected from the vicinity of the houses show that radon mass exhalation rate varied from below detectable limit (BDL) to a maximum of 80 mBq/kg/h. The thoron surface exhalation rate ranged from BDL to 17470 Bq/m2/h.

Outdoor and indoor natural background gamma radiation across Kerala, India

“…21,22 Wayanad and Idukki are the two districts that fall in the high altitude region. Both have an average elevation of 903 MSL (Wayanad) 23 and 1200 MSL (Idukki), 24 respectively. Neutron contribution from cosmic rays uctuates from 8% near the sea level to about 35% 4000 meters 25 The annual average dose values recorded for Wayanad and Idukki were 0.66 mGy per year and 1.06 mGy per year, respectively.…”

Radon Concentration Level in Selected offices at Bells University of Technology, Ota, Ogun State

“…It is a process in which a body emits energy that travels through empty space in the form of waves or particles to be absorbed by another body. The exposure of human to background radiation that emanates from Naturally Occurring Radionuclides is one of the scientific subjects that attracts public attention because exposure to high level of radiation can cause somatic and genetic effects which can result to the damage of some radiosensitive organ of the body and it can eventually lead to death [1,2]. The decay of some naturally occurring radionuclide such as radon, thorium, uranium and potassium are responsible for most background radiation that humans are exposed to on daily bases.…”

A Case Study of the Radon Hazard at the Boundary of a Coal Minefield

“…Inhaling radon provides about 50 percent of the average human ionizing radiation exposure dose and provides a significant additional risk of lung cancer in the human population [1,2]. Inhaled radon and its short-living progeny emit high-LET (linear energy transfer) alpha particles, inducing local exposure and leading to DNA damage in airways and alveolar tissue [3,4].…”