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1 個解答

  • Amby
    Lv 6
    1 十年前


    Polonium is a highly radioactive and toxic element and is very difficult to handle. Even in milligram or microgram amounts, handling 210Po is extremely dangerous, requiring specialized equipment and strict handling procedures. Alpha particles emitted by polonium will damage organic tissue easily if polonium is ingested, inhaled, or absorbed (though they do not penetrate the epidermis and hence are not hazardous if the polonium is outside the body).

    The committed effective dose equivalent (CEDE) of 5.14×10−7 sieverts per becquerel (1.9×103 mrem/microcurie) for ingested 210Po, this value is vital for working out the cancer risk associated with 210Po. For an assessment of acute effects (radiation sickness) the dose rate (Gy day-1) is more important than the committed dose which is a dose inflicted over many years.[17] If the polonium is inhaled, the CEDE is even higher, 2.54×10-6 Sv/Bq or 9.43×103 mrem/microcurie.

    In rats a dose of 1.45 MBq/kg of 210Po tends to cause death in about 30 days.[18]

    The maximum allowable body burden for ingested polonium is only 1,100 becquerels (0.03 microcurie), which is equivalent to a particle weighing only 6.8 × 10-12 gram. Weight for weight, polonium is approximately 2.5 × 1011 (250 billion) times as toxic as hydrogen cyanide. The maximum permissible concentration for airborne soluble polonium compounds is about 7,500 Bq/m3 (2 × 10-11 µCi/cm3). The biological half-life of polonium in humans is 30 to 50 days.[19]