Gamma-dose rates from terrestrial and Chernobyl radionuclides inside and outside settlements in the Bryansk Region, Russia in 1996–2003

Title: Gamma-dose rates from terrestrial and Chernobyl radionuclides inside and outside settlements in the Bryansk Region, Russia in 1996–2003

Author: Valery Ramzaev, Hidenori Yonehara, Ralf Hille, Anatoly Barkovsky, Arkady Mishine, Sarat Kumar Sahoo, Katsumi Kurotaki, Masafumi Uchiyama

Reference: Journal of Environmental Radioactivity, Volume 85, Issues 2–3, 2006, Pages 205-227

DOI: http://dx.doi.org/10.1016/j.jenvrad.2004.04.014

Keywords: Chernobyl accident; Cesium; Terrestrial radionuclides; Gamma-dose rates; Effective doses

Abstract: In order to estimate current external gamma doses to the population of the Russian territories contaminated as a result of the Chernobyl accident, absorbed gamma-dose rates in air (DR) were determined at typical urban and suburban locations. The study was performed in the western districts of the Bryansk Region within the areas of 30 settlements (28 villages and 2 towns) with the initial levels of ¹³⁷Cs deposition ranging from 13 to 4340 kBq m⁻². In the towns, the living areas considered were private one-story wooden and stone houses. DR values were derived from in situ measurements performed with the help of gamma-dosimeters and gamma-spectrometers as well as from the results of soil samples analysis. In the areas under study, the values of DR from terrestrial radionuclides were 25 ± 6, 24 ± 5, 50 ± 10, 32 ± 6, 54 ± 11, 24 ± 8, 20 ± 6, 25 ± 8, and 18 ± 5 nGy h⁻¹ at locations of kitchen gardens, dirt surfaces, asphalt surfaces, wooden houses, stone houses, grasslands inside settlement, grasslands outside settlement, ploughed fields, and forests, respectively. In 1996–2001, mean normalized (per MBq m⁻² of ¹³⁷Cs current inventory in soil) values of DR from ¹³⁷Cs were 0.41 ± 0.07, 0.26 ± 0.13, 0.15 ± 0.07, 0.10 ± 0.05, 0.05 ± 0.04, 0.48 ± 0.12, 1.04 ± 0.22, 0.37 ± 0.07, and 1.15 ± 0.19 μGy h⁻¹ at the locations of kitchen gardens, dirt surfaces, asphalt surfaces, wooden houses, stone houses, grasslands inside settlement, grasslands outside settlement, ploughed fields, and forests, respectively. The radiometric data from this work and the values of occupancy factors determined for the Russian population by others were used for the assessments of annual effective doses to three selected groups of rural population. The normalized (per MBq m⁻²¹³⁷Cs current ground deposition) external effective doses to adults from ¹³⁷Cs ranged from 0.66 to 2.27 mSv y⁻¹ in the years 1996–2001, in accordance with professional activities and structures of living areas. For the areas under study, the average external effective doses from ¹³⁷Cs were estimated to be in the range of 0.39–1.34 mSv y⁻¹ in 2001. The average external effective doses from natural radionuclides appeared to be lower than those from the Chernobyl fallout ranging from 0.15 to 0.27 mSv y⁻¹.

URL: http://www.sciencedirect.com/science/article/pii/S0265931X05002171