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Equilibrium of Radiocesium with Stable Cesium within the Biological Cycle of Contaminated Forest Ecosystems
https://repo.qst.go.jp/records/67464
https://repo.qst.go.jp/records/6746436a29103-eedc-4c81-919a-549a66750600
| Item type | 会議発表用資料 / Presentation(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2003-09-11 | |||||
| タイトル | ||||||
| タイトル | Equilibrium of Radiocesium with Stable Cesium within the Biological Cycle of Contaminated Forest Ecosystems | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_c94f | |||||
| 資源タイプ | conference object | |||||
| アクセス権 | ||||||
| アクセス権 | metadata only access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_14cb | |||||
| 著者 |
Yoshida, Satoshi
× Yoshida, Satoshi× Muramatsu, Yasuyuki× Linkov, I.× Dvornik, A.× Zhuchenko, T.× 吉田 聡× 村松 康行 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | Large areas of forests in the world have been contaminated by radiocesium, 137Cs (half life: 30.0 year) and 134Cs (half life: 2.1 year), discharged from nuclear weapons testing and/or nuclear accidents. Many studies on the distribution and transfer of radiocesium in forest ecosystems were carried out mainly in the European forests after the Chernobyl accident in 1986. Higher concentrations of radiocesium in mushrooms were observed in comparison to plants in the forests. Even more than a decade after deposition, radiocesium is kept in the forests mainly in the organic soil layers, and radiocesium contamination of forest products is still high in contrast to agricultural products. Fungal and microbiological activity is likely to contribute substantially to the long-term retention of radionuclides in organic layers of forest soil. Radiocesium is expected to be stored predominantly within fungal biomass below ground. In order to decide the remediation strategies, prediction of the long-term behavior of radiocesium in the contaminated forests is required. The experimental measurements have provided information for the development of models, which explain radiocesium transport through several compartments in a forest ecosystem. However, the fate of radiocesium in the forest ecosystems is still difficult to predict. As the chemical behavior of radiocesium is expected to be almost identical to that of stable Cs, analyses of stable Cs should be useful to understand the long-term behavior of radiocesium and its equilibrium distribution. Recently we observed a good correlation between 137Cs and stable Cs in mushrooms collected from the same forest. The 137Cs/stable Cs ratio might be a useful criterion for judging the equilibrium of deposited 137Cs to stable Cs in a forest ecosystem. However, the relationship in the whole forest ecosystem is still unknown because of lack of analytical data. In this study, the concentrations of 137Cs and stable Cs were determined for several kinds of samples collected in forests with different contamination levels in Belarus. Samples were collected in 1998 in four different pine forests with different contamination levels in Belarus. At each forest, pines (needles with different age, branches, barks, woods), shrubs, mosses, mushrooms, and soils with different depth were sampled. They were dried and powdered. Activity concentration of radiocesium was determined by Ge-detector coupled to multi-channel analyzer. For stable element analyses, samples were decomposed with acids by using microwave oven. Diluted solutions were analyzed for stable Cs and related elements by ICP-MS and ICP-AES. The activity concentration of 137Cs in soil was the highest in the surface organic layers and decreased with soil depth. Contrastively, the concentrations of stable Cs in soils were almost constant with depth. The levels of 137Cs and stable Cs in plants, mosses and mushrooms were different depend on the species. The samples collected from different parts of trees also showed different concentrations of 137Cs and stable Cs. Although several different species of plants and mushrooms are included, a good correlation between 137Cs and stable Cs was observed for each sampling site independently. The 137Cs/stable Cs ratios in plants, mosses, mushrooms and soil organic layers observed for each site were about the same. This finding suggests that 137Cs, deposited on the forest ecosystems from the Chernobyl accident, was well mixed with stable Cs within the biological cycle in the system in 1998. Fungal and microbiological activity might play an important role on the mixing and the long-term retention of radiocesium. |
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| 会議概要（会議名, 開催地, 会期, 主催者等） | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | 第16回国際環境生物地球化学シンポジウム | |||||
| 発表年月日 | ||||||
| 日付 | 2003-09-06 | |||||
| 日付タイプ | Issued | |||||
