Abstract
During the 1990s, neither atmospheric nuclear test has been conducted nor the severe nuclear accident has occurred, which resulted in no severe contamination in the atmosphere. Therefore, the current atmospheric radioactivity levels became extremely low, giving rise to insignificant public exposure. However, long-term monitoring of anthropogenic radioactivity in atmospheric deposition seems still important in terms of the environmental process study. In fact, the monitoring has revealed the process, so-called resuspension. In order to investigate the resuspension, 137Cs/ 90Sr activity ratios in the deposition were compared with those in surface soil samples. It was found that the 137Cs/ 90Sr ratio in the deposition samples at the MRI, Japan during the 1990s (average: 2.1) was not close to that of the Japanese surface soils (average: 4.5-7), which had been considered as the primary source. The findings suggest that the current radioactivity deposition is not composed of a single local component but a mixture of local and remote resuspension sources. This further lead to our noble hypothesis that large scale aeolian dust may play an important role as a remote source for the resuspension. [J Radiat Res 44:378-379 (2003)]
