Sedimentary record of plutonium in the North Yellow Sea and the response to catchment environmental changes of inflow rivers

Yihong Xu, Shaoming Pan*, Jianhua Gao, Xiaolin Hou, Yongfu Ma, Yongpei Hao

*Corresponding author for this work

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    Abstract

    Plutonium (Pu) isotopes were first determined in surface and core sediment samples collected from the northern North Yellow Sea (NYS) to elucidate their source terms and deposition process as well as the response to catchment environmental changes of inflow rivers. 240Pu/239Pu atom ratios in all sediments showed the typical global fallout value of ∼0.18 without any influences from the nuclear weapons tests conducted recently in the North Korea or early in the Pacific Proving Ground. The large variation of 239+240Pu activities (0.022–0.515 mBq/g) observed in surface sediments should be mainly attributed to the re-suspension and transportation of fine sediments influenced by the Liaonan Costal Current. Based on the two 239+249Pu depth profiles with easily observed onset fallout levels (1952) and global fallout peaks (1963), 239+240Pu served as a valid time mark in the coastal sedimentary system. Riverine input Pu contributed only 15–27% to the total global fallout inventory (92.5–108.8 Bq/m2) in the northern NYS, much lower than that in the Yangtze River estuary (77–80%), indicating a better soil conservation in the northeast China due to higher forest coverage compared to the Yangtze River's drainage basin. The increase of riverine input Pu after 1980s reflected the more intense soil erosion degree caused by the land use and cover change due to the increment of human activities in the northeast China at the same period. Our results demonstrated that plutonium is a good indicator for studying sedimentary process and its response to the environment in the coastal area.
    Original languageEnglish
    JournalChemosphere
    Volume207
    Pages (from-to)130-138
    Number of pages9
    ISSN0045-6535
    DOIs
    Publication statusPublished - 2018

    Keywords

    • Plutonium
    • North Yellow Sea
    • Sediment
    • Isotopic ratio
    • Chronological marker
    • Riverine input

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