5:15 PM - 6:45 PM
[MAG33-P07] Soil Sample Archives from the Nagasaki Atomic Bombing Radioactive Fallout area
Keywords:Radioactive fallout, Atomic bomb soil sample, Archive
[Introduction] Nagasaki University has been measuring the radioactivity of soil samples collected mainly in Nagasaki Prefecture since 1969, starting with soil samples from the source of water in the Nishiyama area of Nagasaki City until around 1981, for the purpose of investigating the effects of residual radioactivity in fallout from the atomic bombing of Nagasaki in 1945. In particular, in the "Report on the Survey of Residual Radioactivity in Hiroshima and Nagasaki" (published by the Japan Public Health Association) in 1976 and 1978, soil samples were collected at 98 sites within a radius of approximately 30 km from the hypocenter and the results of the radioactivity measurements were reported. These soil samples were stored in a basement room, Nagasaki University, and remained unnoticed for about half a century. This report describes the organization of soil samples, the creation of a database, the maintenance of a public sample room, and the construction of the Nagasaki A-bomb soil sample archive.
[Methods] The soil samples were stored in individual containers as fine soil samples with information such as collection date, collection site number, and stratigraphy. The soil samples included uncultivated soil, crop soil (soil surrounding crops grown in the field), bricks, and concrete chips. First, these samples were assigned physical sample numbers as existing samples and refilled into new containers. On the other hand, in the 1980s, a handwritten "Soil Collection Record Book" was created and detailed information about the soil samples collected was kept, and these records were assigned record sample numbers. All information on the physical and archival samples is included in the A-bomb Database at Nagasaki University. The physical sample numbers were matched to the record sample numbers, and more than 90% of the physical samples were matched to the records. All 1,283 samples, which had been identified and repackaged in new containers, were re-stored in humidity-controlled vaults with shelf numbers. The information recorded in the A-bomb Database at Nagasaki University has been extracted and imported into the Database of Atomic Bomb Samples (DABS) using a processing program. DABS is utilized to visualize sampling locations and radioactivity on a map, as well as to conduct time-series analysis of the measurement results.
[Conclusion] Through the construction of the soil sample archive, the "Archives of environmental materials by A-bomb-derived radioactive fallout" was newly established in the Nagasaki University Museum of Medicine and opened to the public in August 2022. In addition, four explanatory videos on A-bombed soil samples have been produced and made publicly available, and students on school excursion tours can view the videos or listen to explanations by technical staff.
Nagasaki University will continue to maintain and manage the archived A-bomb soil samples under its responsibility, and in the future will establish a system to provide samples for new analytical methods for A-bomb and radioactive fallout traces.
Acknowledgements:We express our gratitude to the Ministry of Health, Labour and Welfare of Japan for funding this study.
[Methods] The soil samples were stored in individual containers as fine soil samples with information such as collection date, collection site number, and stratigraphy. The soil samples included uncultivated soil, crop soil (soil surrounding crops grown in the field), bricks, and concrete chips. First, these samples were assigned physical sample numbers as existing samples and refilled into new containers. On the other hand, in the 1980s, a handwritten "Soil Collection Record Book" was created and detailed information about the soil samples collected was kept, and these records were assigned record sample numbers. All information on the physical and archival samples is included in the A-bomb Database at Nagasaki University. The physical sample numbers were matched to the record sample numbers, and more than 90% of the physical samples were matched to the records. All 1,283 samples, which had been identified and repackaged in new containers, were re-stored in humidity-controlled vaults with shelf numbers. The information recorded in the A-bomb Database at Nagasaki University has been extracted and imported into the Database of Atomic Bomb Samples (DABS) using a processing program. DABS is utilized to visualize sampling locations and radioactivity on a map, as well as to conduct time-series analysis of the measurement results.
[Conclusion] Through the construction of the soil sample archive, the "Archives of environmental materials by A-bomb-derived radioactive fallout" was newly established in the Nagasaki University Museum of Medicine and opened to the public in August 2022. In addition, four explanatory videos on A-bombed soil samples have been produced and made publicly available, and students on school excursion tours can view the videos or listen to explanations by technical staff.
Nagasaki University will continue to maintain and manage the archived A-bomb soil samples under its responsibility, and in the future will establish a system to provide samples for new analytical methods for A-bomb and radioactive fallout traces.
Acknowledgements:We express our gratitude to the Ministry of Health, Labour and Welfare of Japan for funding this study.