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Drozdovitch V, Kukhta T, Trofimik S, Melo DR, Viarenich K, Podgaiskaya M, Minenko V. Doses from external irradiation and ingestion of 134Cs, 137Cs and 90Sr of the population of Belarus accumulated over 35 years after the Chernobyl accident. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2022; 61:445-464. [PMID: 35767189 PMCID: PMC10084818 DOI: 10.1007/s00411-022-00979-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 06/04/2022] [Indexed: 06/15/2023]
Abstract
This study considers the exposure of the population of the most contaminated Gomel and Mogilev Oblasts in Belarus to prolonged sources of irradiation resulting from the Chernobyl accident. Dose reconstruction methods were developed and applied in this study to estimate the red bone-marrow doses (RBMs) from (i) external irradiation from gamma-emitting radionuclides deposited on the ground and (ii) 134Cs, 137Cs and 90Sr ingestion with locally produced foodstuffs. The mean population-weighted RBM doses accumulated during 35 years after the Chernobyl accident were 12 and 5.7 mGy for adult residents in Gomel and Mogilev Oblasts, respectively, while doses for youngest age groups were 20-40% lower. The highest mean area-specific RBM doses for adults accumulated in 1986-2021 were 63, 56 and 46 mGy in Narovlya, Vetka and Korma raions in Gomel Oblast, respectively. For most areas, external irradiation was the predominant pathway of exposure (60-70% from the total dose), except for areas with an extremely high aggregated 137Cs soil to cow's milk transfer coefficient (≥ 5.0 Bq L-1 per kBq m-2), where the contribution of 134Cs and 137Cs ingestion to the total RBM dose was more than 70%. The contribution of 90Sr intake to the total RBM dose did not exceed 4% for adults and 10% for newborns in most raion in Gomel and Mogilev Oblasts. The validity of the doses estimated in this study was assessed by comparison with doses obtained from measurements by thermoluminescence dosimeters and whole-body counters done in 1987-2015. The methodology developed in this study can be used to calculate doses to target organs other than RBM such as thyroid and breast doses. The age-dependent and population-weighted doses estimated in this study are useful for ecological epidemiological studies, for projection of radiation risk, and for justification of analytical epidemiological studies in populations exposed to Chernobyl fallout.
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Affiliation(s)
- Vladimir Drozdovitch
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, 9609 Medical Center Drive, Room 7E548 MSC 9778, Bethesda, MD, 20892-9778, USA.
| | - Tatiana Kukhta
- United Institute of Informatics Problems, National Academy of Sciences of Belarus, Minsk, Belarus
| | - Sergey Trofimik
- Institute for Nuclear Problems, Belarusian State University, Minsk, Belarus
| | | | - Kiryl Viarenich
- Institute for Nuclear Problems, Belarusian State University, Minsk, Belarus
| | - Marina Podgaiskaya
- Republican Center of Radiation Control and Environmental Monitoring, 220023, Minsk, Belarus
| | - Victor Minenko
- Institute for Nuclear Problems, Belarusian State University, Minsk, Belarus
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Drozdovitch V, Minenko V, Kukhta T, Viarenich K, Trofimik S, Rogounovitch T, Nakayama T, Drozd V, Veyalkin I, Mitsutake N, Ostroumova E, Saenko V. Thyroid dose estimates for the genome-wide association study of thyroid cancer in persons exposed in Belarus to 131I after the Chernobyl accident. JOURNAL OF RADIATION RESEARCH 2021:rrab082. [PMID: 34536956 DOI: 10.1093/jrr/rrab082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 07/26/2021] [Indexed: 06/13/2023]
Abstract
The Chernobyl accident on 26 April 1986 led to a sharp increase in thyroid cancer (TC) incidence in the individuals exposed to radiation in childhood. The major risk factor for TC was exposure to Iodine-131 (131I). Here, we estimated the thyroid doses due to 131I intake for 2041 participants of the genome-wide association study of TC in Belarusian people exposed to radioactive fallout from the Chernobyl accident. The following parameter-values specially developed in this study were used to estimate individual thyroid doses: (i) scaling factors for adjustment of the model-based doses, (ii) age and gender diet to characterize 131I intake, and (iii) area-, age- and gender-specific S-values for the thyroid gland per 131I decay in the thyroid. The most reliable doses were calculated for 103 people with measured 131I thyroid activity (the arithmetic mean of 1.2 Gy, median 0.52 Gy), and 275 individuals with detailed residential history and dietary data (the arithmetic mean of 0.41 Gy, median 0.24 Gy). The arithmetic mean of thyroid doses among all study participants was 0.23 Gy (median 0.082 Gy); the highest individual dose was 9.0 Gy. Special attention was paid to the reliability and validity of the obtained estimates, in particular for the individuals without 131I thyroid activity measurements and individual data on residential history and diet, by comparing those with the doses from other post-Chernobyl epidemiological studies. Overall, the doses estimated in the current study were in reasonable agreement with previously reported thyroid doses. These doses will be used in the genome-wide association study of TC in people exposed in Belarus to 131I after the Chernobyl accident.
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Affiliation(s)
- Vladimir Drozdovitch
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD 20892, USA
| | - Victor Minenko
- Institute for Nuclear Problems, Belarusian State University, Minsk, 220030, Belarus
| | - Tatiana Kukhta
- United Institute of Informatics Problems, National Academy of Sciences of Belarus, Minsk, 220012, Belarus
| | - Kiryl Viarenich
- Institute for Nuclear Problems, Belarusian State University, Minsk, 220030, Belarus
| | - Sergey Trofimik
- Institute for Nuclear Problems, Belarusian State University, Minsk, 220030, Belarus
| | - Tatiana Rogounovitch
- Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, 852-8523, Japan
| | - Takafumi Nakayama
- Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, 852-8523, Japan
| | - Valentina Drozd
- The International Fund "Help for Patients with Radiation-Induced Thyroid Cancer 'Arnica'", Minsk, 220005, Belarus
| | - Ilya Veyalkin
- Republican Research Center for Radiation Medicine and Human Ecology, Gomel, 246040, Belarus
| | - Norisato Mitsutake
- Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, 852-8523, Japan
| | - Evgenia Ostroumova
- International Agency for Research on Cancer, WHO, 69372, Lyon CEDEX 08, France
| | - Vladimir Saenko
- Department of Radiation Molecular Epidemiology, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, 852-8523, Japan
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Kukhta T, Minenko V, Trofimik S, Drozdovitch V. Reliability of thyroid doses due to 131I intake exceeding 5 Gy in a cohort of Belarusian children exposed to Chernobyl fallout. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2021; 60:179-191. [PMID: 33392786 PMCID: PMC7904619 DOI: 10.1007/s00411-020-00882-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 11/17/2020] [Indexed: 06/12/2023]
Abstract
High thyroid doses due to Iodine-131 (131I) intake among individuals exposed in childhood and adolescence to Chernobyl fallout raise questions about their reliability and their impact on the analysis of the radiation-related risk of thyroid cancer and other thyroid diseases in the exposed population. In the present study, an in-depth examination was conducted of thyroid doses from 131I intake over 5 Gy calculated for 131 subjects of the Belarusian-American cohort of individuals exposed after the Chernobyl accident. Thyroid doses in this cohort study were estimated based on individual radiation measurements of 131I thyroidal activity and detailed questionnaire data on individual behavior and consumptions of locally produced foodstuffs. Therefore, these doses provide the best basis for assessing reliability. The analysis showed that the result of direct thyroid measurement was mistakenly assigned to three out of 131 study subjects (2.3% of the total), and, therefore, the instrumental thyroid dose for these individuals cannot be correctly estimated. This study confirmed with a high degree of confidence the reliability of thyroid doses due to 131I intake exceeding 5 Gy that were calculated for the Belarusian-American cohort members.
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Affiliation(s)
- Tatiana Kukhta
- United Institute of Informatics Problems of the National Academy of Sciences of Belarus, Minsk, Belarus
| | - Victor Minenko
- Institute for Nuclear Problems, Belarusian State University, Minsk, Belarus
| | - Sergey Trofimik
- Institute for Nuclear Problems, Belarusian State University, Minsk, Belarus
| | - Vladimir Drozdovitch
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, 9609 Medical Center Drive, Room 7E548 MSC 9778, Bethesda, MD, 20892-9778, USA.
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Drozdovitch V. Radiation Exposure to the Thyroid After the Chernobyl Accident. Front Endocrinol (Lausanne) 2020; 11:569041. [PMID: 33469445 PMCID: PMC7813882 DOI: 10.3389/fendo.2020.569041] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 11/17/2020] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION The Chernobyl accident resulted in a considerable release of radioactivity to the atmosphere, particularly of Iodine-131 (131I), with the greatest contamination occurring in Belarus, Ukraine, and western part of Russia. MATERIAL AND METHODS Increase in thyroid cancer and other thyroid diseases incidence in population exposed to Chernobyl fallout in these counties was the major health effect of the accident. Therefore, a lot of attention was paid to the thyroid doses, mainly, the 131I intake during two months after the accident. This paper reviews thyroid doses, both the individual for the subjects of radiation epidemiological studies and population-average doses. Exposure to 131I intake and other exposure pathways to population of affected regions and the Chernobyl cleanup workers (liquidators) are considered. RESULTS Individual thyroid doses due to 131I intake varied up to 42 Gy and depended on the age of the person, the region where a person was exposed, and their cow's milk consumption habits. Population-average thyroid doses among children of youngest age reached up to 0.75 Gy in the most contaminated area, the Gomel Oblast, in Belarus. Intake of 131I was the main pathway of exposure to the thyroid gland; its mean contribution to the thyroid dose in affected regions was more than 90%. The mean thyroid dose from inhalation of 131I for early Chernobyl cleanup workers was estimated to be 0.18 Gy. Individual thyroid doses due to different exposure pathways varied among 1,137 cleanup workers included in the epidemiological studies up to 9 Gy. Uncertainties associated with dose estimates, in terms of mean geometric standard deviation of individual stochastic doses, varied in range from 1.6 for doses based on individual-radiation measurements to 2.6 for "modelled" doses. CONCLUSION The 131I was the most radiologically important radionuclide that resulted in radiation exposure to the thyroid gland and cause an increase in the of rate of thyroid cancer and other thyroid diseases in population exposed after the Chernobyl accident.
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