Cerium in Mammalian Species

Radiocerium absorbed into the systemic circulation will be transported by blood proteins and be deposited predominantly in liver and bone. Deposition fractions will be about 0.45 for liver, 0.35 for bone, and 0.1 for other soft tissues with the remainder excreted in urine and feces. The retention times in liver and bone are long compared to the radioactive half-lives of the cerium isotopes. Therefore, their effective biological half-times in these organs will be approximately equal to their physical half-lives. Experimental data on internal organ distri- 

Variations in radiation doses to individuals within exposed populations also occur. Based upon previous exposures of people to Pu and Sr in fallout and exposures of laboratory animals to Ce, the dispersion of individual doses in a population is expected to be significant and should be considered in the formulation of population exposure guidelines. 

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To develop a better understanding of the potential health consequences of radiocerium in our environment, it is important to know the possible sources and physical and chemical forms of its release. The metabolism and dosimetry of internally-deposited radiocerium are highly dependent upon the forms of the material presented to the body and the mode of exposure as discussed in Section 3—Metabolism of Cerium in Mammalian Species. 

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