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Plutonium activities and 240Pu/239Pu atom ratios in sediment cores from the East China Sea and Okinawa Trough: Sources and inventories
https://repo.qst.go.jp/records/43971
https://repo.qst.go.jp/records/43971514f2337-d080-4b67-a7fc-4396f68e79c8
| Item type | 学術雑誌論文 / Journal Article(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2006-01-30 | |||||
| タイトル | ||||||
| タイトル | Plutonium activities and 240Pu/239Pu atom ratios in sediment cores from the East China Sea and Okinawa Trough: Sources and inventories | |||||
| 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_6501 | |||||
| 資源タイプ | journal article | |||||
| 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 |
Wang, Zhong-Liang
× Wang, Zhong-Liang× Yamada, Masatoshi× 王 中良× 山田 正俊 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | Plutonium concentrations and 240Pu/239Pu atom ratios in the East China Sea and Okinawa Trough sediment cores were determined by isotope dilution inductively coupled plasma mass spectrometry after separation using ion-exchange chromatography. The results showed that 240Pu/239Pu atom ratios in the East China Sea and Okinawa Trough sediments, ranging from 0.21 to 0.33, were much higher than the reported value of global fallout (0.18). The highest 240Pu/239Pu ratios (0.32-0.33) were observed in the deepest Okinawa Trough sediment samples. These ratios suggested the US nuclear weapons tests in the early 1950's at the Pacific Proving Grounds in the Marshall Islands were a major source of plutonium in the East China Sea and Okinawa Trough sediments, in addition to the global fallout source. It was proposed that close-in fallout plutonium was delivered from the Pacific Proving Grounds test sites via early direct tropospheric fallout and transportation by the North Pacific Equatorial Circulation system and Kuroshio Current into the Okinawa Trough and East China Sea. The total 239+240Pu inventories in the cores were about 150-200 % of that expected from direct global fallout; about 46-67 % of the total inventories were delivered from the Pacific Proving Grounds. Much higher 239+240Pu inventories were observed in the East China Sea sediments than in sediments of the Okinawa Trough, because in the open oceans, part of the 239+240Pu was still retained in the water column, and continued Pu scavenging was higher over the margin than the trough. According to the vertical distributions of 239+240Pu activities and 240Pu/239Pu atom ratios in these cores, it was concluded that sediment mixing was the dominant process in controlling profiles of plutonium in this area. Faster mixing in the coastal samples has homogenized the entire 240Pu/239Pu ratio record today; slightly slower mixing and less scavenging in the Okinawa Trough has left the surface sediment ratios closer to the modern North Pacific water end member and higher ratios (0.30-0.34) at the bottom of the cores. | |||||
| 書誌情報 |
Earth and Planetary Science Letters 巻 233, 号 3-4, p. 441-453, 発行日 2005-05 |
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| ISSN | ||||||
| 収録物識別子タイプ | ISSN | |||||
| 収録物識別子 | 0012-821X | |||||
