{"created":"2023-05-15T14:49:27.227234+00:00","id":67718,"links":{},"metadata":{"_buckets":{"deposit":"7e01e87e-461a-4a1a-982a-f9d33a994520"},"_deposit":{"created_by":1,"id":"67718","owners":[1],"pid":{"revision_id":0,"type":"depid","value":"67718"},"status":"published"},"_oai":{"id":"oai:repo.qst.go.jp:00067718","sets":["10:28"]},"author_link":["665493","665496","665495","665494"],"item_10005_date_7":{"attribute_name":"発表年月日","attribute_value_mlt":[{"subitem_date_issued_datetime":"2004-03-04","subitem_date_issued_type":"Issued"}]},"item_10005_description_5":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"In a series of investigation on the distribution of Pu in the Pacific marginal sediments, general excess inventories of Pu over those anticipated from global fallout were observed. It has been speculated that the main source of these excess inventories could be close-in and tropospheric fallout derived from large scale nuclear explosions on Bikini and Enewetok atolls prior to 1964. However, no direct evidence was found to support this hypothesis. \n   It was known that the isotopic signature of Pu, in particular the atom ratio of 240Pu/239Pu is a useful fingerprint to identify the source of Pu in the environment, because Pu released from different sources has its characteristic 240Pu/239Pu ratio. Recently, we investigated the applicability of quadrupole ICP-MS for the determination of Pu and its isotope ratio in marine sediments. The shield torch technique was explored as a way to improve detection sensitivity of actinides. We demonstrated that, when combined with a simple ion-chromatographic separation procedure, the conventional quadrupole ICP-MS with the shield torch system under normal plasma conditions, which offers sufficiently low detection limits, can be readily applied to the determination of Pu in marine sediment samples. From the Pu isotope ratio signature obtained in sediment core samples, we identified two isotopically distinct sources of fallout Pu in Sagami Bay, Japan: the global fallout Pu and the transported Bikini close-in fallout Pu.   \n   The sediment core record of global fallout and Bikini close-in fallout Pu, solved a long term puzzle about the sources of Pu in Sagami Bay. It clearly indicates that Pu contamination which originated from Bikini and Enewetak nuclear test series in the 1950s has extended westwards as far as the Japanese coast, probably through the surface oceanic currents, e.g. the North Equatorial and Kuroshio currents. Using a two fallout end-member model, we found that the Bikini close-in fallout was a major source of Pu in Sagami Bay, its contribution ranged from 44 -59 %. Further study will focus on the Pu scavenging process by biogenic and inorganic particles, thus to elucidate the details of oceanic Pu transportation process.","subitem_description_type":"Abstract"}]},"item_10005_description_6":{"attribute_name":"会議概要（会議名, 開催地, 会期, 主催者等）","attribute_value_mlt":[{"subitem_description":"第５回環境放射能研究会","subitem_description_type":"Other"}]},"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":"Zheng, Jian"}],"nameIdentifiers":[{"nameIdentifier":"665493","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"Yamada, Masatoshi"}],"nameIdentifiers":[{"nameIdentifier":"665494","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"鄭 建","creatorNameLang":"en"}],"nameIdentifiers":[{"nameIdentifier":"665495","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"山田 正俊","creatorNameLang":"en"}],"nameIdentifiers":[{"nameIdentifier":"665496","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":"conference object","resourceuri":"http://purl.org/coar/resource_type/c_c94f"}]},"item_title":"Application of ICP-MS to the source identification of Pu in marine sediments","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Application of ICP-MS to the source identification of Pu in marine sediments"}]},"item_type_id":"10005","owner":"1","path":["28"],"pubdate":{"attribute_name":"公開日","attribute_value":"2004-03-04"},"publish_date":"2004-03-04","publish_status":"0","recid":"67718","relation_version_is_last":true,"title":["Application of ICP-MS to the source identification of Pu in marine sediments"],"weko_creator_id":"1","weko_shared_id":-1},"updated":"2023-05-15T20:34:30.522377+00:00"}