1. How dynamic transfer models can complement an equilibrium-based approach: Case studies of radiocesium transfer to forest trees following accidental atmospheric release.
- Author
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Tanaka T and Thiry Y
- Subjects
- Trees, Forests, Cesium Radioisotopes analysis, Japan, Soil Pollutants, Radioactive analysis, Fukushima Nuclear Accident, Radiation Monitoring
- Abstract
Accidental release of radionuclides caused by nuclear accidents like those in Fukushima and Chernobyl can result in pulses of radioactivity entering the forest environment. Due to intense recycling in the forest, equilibrium between radioactivity concentrations in trees and in soil may not be reached during the period of short-term radionuclide transport following the accident. Another question arises as to whether the equilibrium hypothesis using empirical concentration ratios (CRs) can be applied to the long-term period. Using two atmospheric
137 Cs fallout scenarios in the Fukushima and Chernobyl sites, this study investigated whether the CR approach could provide conservative predictions of137 Cs levels in trees following137 Cs fallout events by comparing predictions from the CR approach using data gathered for trees by the IAEA to those from dynamic transfer models and actual measured data. The inter-comparisons also aimed to investigate whether the CR approach could account for the variability of137 Cs levels across different tree organs. The results showed that caution may be necessary when using the CR approach, which relies on the IAEA dataset, to estimate137 Cs accumulation in forest trees in the short - and long term following atmospheric137 Cs fallout events. A calculation by TRIPS 2.0 demonstrated the importance of considering the distribution within tree organs for in-depth analysis of radiological impact of forest trees. Our findings suggest that it may be preferable to use CR values based on site-specific data rather than generic data collected from various sites. This is particularly relevant when studying the sites where the bioavailability of137 Cs for trees and thus possible exposures are higher. This study also showed that dynamic modeling approaches could offer an alternative means of estimating CR values of the entire tree or specific tree organs in situations where empirically derived values are not available., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)- Published
- 2023
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