EAPSI: Spatial estimation of early radioactive fallout from the Hiroshima atomic bomb

Kelly-Reif Kaitlin E, Carrboro NC

Investigators

Abstract

In 1945, a uranium atomic bomb was dropped on Hiroshima, Japan. Victims of the atomic bomb experienced direct doses of radiation from the blast, but radioactive particles were also suspended into the atmosphere and deposited farther from the bomb's epicenter. These distal exposures are known as radioactive fallout and exposure is of concern to victims of the atomic bomb and their families. Researchers are studying health effects of radiation because it is possible that persons more distal from the atomic blast center received significant doses of radiation from fallout. Some measurements of fallout were taken by different research organizations during the days following the bombings but they were sparse and have not been utilized widely due to differences in measurement techniques. This project will join data from early surveys to estimate levels of early fallout from the atomic bomb, and produce a singular map of fallout. This project will be conducted at the Radiation Effects Research Foundation in collaboration with Dr. Harry Cullings, an expert in atomic bomb dosimetry. Using geospatial statistical methods, hierarchical models, and substantive physics knowledge, this study will model early radiation exposure in the Koi-Takasu area. Combining early surveys while considering survey timing in relation to radioactive decay of the fallout, the precision of each survey's measurements, and possible differences in calibration among surveys will allow spatial modeling of time-specific and integrated gamma-ray exposure rates. Early radiation exposure is important to characterize in order to better inform dosimetry research and other studies with biological endpoints, particularly the Life Span Study, which informs radiation protection standards worldwide. This NSF EAPSI award is funded in collaboration with the Japan Society for the Promotion of Science.