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238Pu: a review of the biokinetics, dosimetry, and implications for human exposures.

Abstract

Plutonium-238 (238Pu) has a half-life of about 87.7 y and thus a higher specific activity than 239Pu. It is used in radioisotope thermoelectric generators and is a substantial source of plutonium alpha-radiation in spent nuclear fuels. Early animal studies demonstrated differences in the biokinetics of inhaled oxides of 238Pu and 239Pu with 238Pu having a substantially more rapid translocation from the lungs to the systemic organs, particularly the skeleton. This resulted in the predominant occurrence of skeletal cancers in animals exposed to 238Pu oxides but lung cancers in those with exposures to 239Pu oxides. The anatomical distribution of osteogenic sarcomas seen in animal studies was similar to that observed with 239Pu and also in plutonium workers but differed from naturally occurring tumors. The in vivo "solubility" of 238Pu has been associated with the relative amounts of 238Pu/239Pu in the particles and calcination temperatures during the preparation of the dioxides. There is experimental evidence of in vivo 238Pu particle fragmentation attributed to nuclear recoil during radioactive decay. The resulting conversion of microparticles to nanoparticles may alter their interactions with macrophages and transport across epithelial barriers. There are few documented cases of human exposures, but the biokinetics appeared to depend on the chemical and physical nature of the aerosols. Robust human biokinetic and dosimetric models have not been developed, due in part to the lack of data. With the acceleration of nuclear technologies and the greater demand for reprocessing and/or disposal of spent nuclear fuels, the potential for human exposure to 238Pu will likely increase in the future.

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  • Publisher Full Text
  • Authors

    Suslova KG, Khokhryakov VF, Sokolova AB, Miller SC

    Source

    Health physics 102:3 2012 Mar pg 251-62

    MeSH

    Aerosols
    Animals
    Bone Neoplasms
    Endocytosis
    Health Physics
    Humans
    Intestinal Absorption
    Lung
    Neoplasms, Radiation-Induced
    Nuclear Reactors
    Occupational Exposure
    Osteosarcoma
    Plutonium
    Radiometry

    Pub Type(s)

    Journal Article
    Research Support, Non-U.S. Gov't
    Research Support, U.S. Gov't, Non-P.H.S.
    Review

    Language

    eng

    PubMed ID

    22420017