Dosimetric impact of natural terrestrial radioactivity on residents of lower Himalayas, India
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ORIGINAL PAPER
Dosimetric impact of natural terrestrial radioactivity on residents of lower Himalayas, India Sarabjot Kaur . Rohit Mehra
Received: 16 May 2020 / Accepted: 9 October 2020 © Springer Nature B.V. 2020
Abstract A comprehensive radio-ecological evaluation of soil samples of Solan and Shimla districts of Himachal Pradesh has been carried out for risk and dose assessment. Twenty-six randomly selected environmental soil samples were analysed for natural radionuclide concentrations (226Ra, 232Th and 40K) using NaI(Tl) scintillator detector. The average concentration of 226Ra, 232Th and 40K was observed as 37, 59 and 430 Bq kg−1, respectively, which exceeded the worldwide average of 33, 45 and 412 Bq kg−1 reported by UNSCEAR (Sources and effects of ionizing radiation. Report to the general assembly with scientific annexes, New York, 2008). Radium equivalent activity (Raeq), hazard indices (Hex, Hin) and radioactivity level indices (Iϒr, Iα, AUI) and Clark value were checked against their threshold limits, and their mean values were safely below the recommended criteria. This confirms the soil applicability for construction purposes. Indoor ˙ ), age-dependent annual and outdoor dose rates (D effective doses (AED), organ-specific doses and lifetime attributable cancer risk (both cancer incidence and cancer mortality) were also computed. Strong positive correlation was established between radon/thoron exhalation rate and their parent
S. Kaur · R. Mehra (&) Environment Monitoring and Assessment Laboratory, Department of Physics, Dr. B R Ambedkar National Institute of Technology, Jalandhar, Punjab 144011, India e-mail: [email protected]
radionuclides. Multivariate statistical technique was employed to explore spatial distribution of radionuclides and homogeneity between various radiological parameters. Keywords Gamma spectroscopy · Radium equivalent · Hazard indices · Annual effective doses · Lifetime attributable risk · Exhalation and emanation rate Abbreviations AR Activity concentration of a particular radionuclide (Bq kg−1) NE Net area of the peak (background subtracted) at energy E T Counting time for a sample in NaI detector (s), 10,800 ϒ Gamma energy yield per disintegration of the specific radionuclide at energy E, 15.1 for 214Bi, 35.64 for 208Tl, 10.67 for 40K ε Absolute full-energy peak detection efficiency of detector at energy E, 1.13 for 226Ra, 0.77 for 232Th, 1.352 for 40K m Total mass of the dry soil sample inside the chamber or container (kg) RB Background count rate of detector tG Gross count time (s) tB Background count time (s) CRn(t) Radon concentration inside the accumulation chamber at any time t≠0 (Bq m−3)
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Environ Geochem Health
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Radon mass exhalation rate (Bq kg−1 h−1) Effective volume (residual air volume of exhalation chamber+Porous Volume of sample+internal volume of SMART RnDuo/RAD7) (m3), 0.0015 Effective radon decay constant which is sum to
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