Investigation of radon and thoron exhalation rates in soils: Manali-Leh Highway region of Himalayas.

This study analyses the natural radionuclides concentration (Ra and Th) along with the radon and thoron exhalation rates in 50 soil samples collected from the Manali-Leh Highway region of the Himalayas. The specific activity of Ra and Th radionuclides was determined using a NaI(Tl) detector, revealing that the concentration values of these radionuclides are lower than the global average. The radon and thoron exhalation rates in the soil samples were measured utilizing a SMART RnDuo detector. The radon mass exhalation rates range from 6 to 87 mBq kg h, with average values of 25 mBq kg h. The thoron surface exhalation rates vary from 110 to 757 Bq m h, with a mean value of 385 Bq m h. Additionally, the emanation coefficient and alpha dose equivalent for radon were calculated and the correlation between parent and daughter radionuclides was also explored.