{"created":"2023-05-15T14:58:45.418244+00:00","id":79710,"links":{},"metadata":{"_buckets":{"deposit":"5cb921cd-c9dd-45b1-9791-ec67cf0f97b2"},"_deposit":{"created_by":1,"id":"79710","owners":[1],"pid":{"revision_id":0,"type":"depid","value":"79710"},"status":"published"},"_oai":{"id":"oai:repo.qst.go.jp:00079710","sets":["1"]},"author_link":["861512","861511","861513"],"item_8_biblio_info_7":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"2020-02","bibliographicIssueDateType":"Issued"},"bibliographicVolumeNumber":"718","bibliographic_titles":[{"bibliographic_title":"Science of the Total Environment"}]}]},"item_8_description_5":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":" Nuclear weapons tests were conducted at the Bikini and Enewetak Atolls in the \n Pacific Proving Grounds (PPG) in the Marshall Islands between 1946 and 1958. The  240Pu/239Pu atom ratios in seawater samples from the northern North Pacific Ocean and Bering Sea were determined to elucidate the temporal variability in 239+240Pu inventory, to identify their Pu sources and to propose the transport pathways of PPG-derived Pu into the studied area. Water column 239+240Pu inventory in the Bering Sea was lower than that reported for a comparable station in the Geochemical Ocean Sections Study, indicating that the Bering Sea inventory has been decreasing from 76.0 ± 3.0 Bq m-2 to 37.1 ± 0.9 Bq m-2 during the period from 1973 to 1988 at the average rate of 2.6 ± 0.2  Bq m-2 yr-1. The 240Pu/239Pu atom ratios in the water column ranged from 0.222 to 0.255 with a mean value of 0.235 ± 0.008 in the northern North Pacific Ocean and from 0.215 to 0.237 with a mean value of 0.224 ± 0.004 in the Bering Sea. The obtained 240Pu/239Pu atom ratios were clearly higher than the mean global stratospheric fallout ratio of 0.18. These high atom ratios proved the existence of close-in tropospheric fallout Pu from nuclear weapons testing at the PPG. The relative contribution of the global stratospheric fallout and the PPG close-in fallout were evaluated by using the two-end-member mixing model. The 239+240Pu inventories originating from the PPG close-in fallout were calculated as 17.9 – 25.4 Bq m-2 in the northern North Pacific Ocean and 11.6 – 16.6 Bq m-2 in the Bering Sea, which corresponded to 38 – 54% and 31 – 45% of the total- 239+240Pu inventory in the water column in the northern North Pacific Ocean and Bering Sea, respectively. A significant amount of the PPG close-in fallout Pu has been transported to the northern North Pacific Ocean and Bering Sea. The proposed transport pathway accounting for the high 240Pu/239Pu atom ratio in the Bering Sea water column is the transportation of PPG-derived Pu by the North Equatorial Current followed by the Kuroshio Current, Kuroshio Extension, North Pacific Current and subsequently the Alaska Current, and then the Alaskan Stream.","subitem_description_type":"Abstract"}]},"item_8_publisher_8":{"attribute_name":"出版者","attribute_value_mlt":[{"subitem_publisher":"Elsevier"}]},"item_8_relation_14":{"attribute_name":"DOI","attribute_value_mlt":[{"subitem_relation_type_id":{"subitem_relation_type_id_text":"10.1016/j.scitotenv.2020.137362","subitem_relation_type_select":"DOI"}}]},"item_8_relation_17":{"attribute_name":"関連サイト","attribute_value_mlt":[{"subitem_relation_type_id":{"subitem_relation_type_id_text":"https://www.sciencedirect.com/science/article/pii/S004896972030872X","subitem_relation_type_select":"URI"}}]},"item_8_source_id_9":{"attribute_name":"ISSN","attribute_value_mlt":[{"subitem_source_identifier":"0048-9697","subitem_source_identifier_type":"ISSN"}]},"item_access_right":{"attribute_name":"アクセス権","attribute_value_mlt":[{"subitem_access_right":"metadata only access","subitem_access_right_uri":"http://purl.org/coar/access_right/c_14cb"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"Yamada, Masatoshi"}],"nameIdentifiers":[{"nameIdentifier":"861511","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"Zheng, Jian"}],"nameIdentifiers":[{"nameIdentifier":"861512","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"Zheng, Jian","creatorNameLang":"en"}],"nameIdentifiers":[{"nameIdentifier":"861513","nameIdentifierScheme":"WEKO"}]}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"journal article","resourceuri":"http://purl.org/coar/resource_type/c_6501"}]},"item_title":"240Pu/239Pu atom ratios in water columns from the North Pacific Oceanand Bering Sea: Transport of Pacific Proving Ground-derived Pu by Ocean Currents","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"240Pu/239Pu atom ratios in water columns from the North Pacific Oceanand Bering Sea: Transport of Pacific Proving Ground-derived Pu by Ocean Currents"}]},"item_type_id":"8","owner":"1","path":["1"],"pubdate":{"attribute_name":"公開日","attribute_value":"2019-11-19"},"publish_date":"2019-11-19","publish_status":"0","recid":"79710","relation_version_is_last":true,"title":["240Pu/239Pu atom ratios in water columns from the North Pacific Oceanand Bering Sea: Transport of Pacific Proving Ground-derived Pu by Ocean Currents"],"weko_creator_id":"1","weko_shared_id":-1},"updated":"2023-05-15T22:07:45.439212+00:00"}