Thorium in human blood serum,clot, and urine comparison with ICRP excretion model

Neutron activation followed by a simple radio-chemical separation procedure was employed to determine the concentrations of thorium (²³²Th) in human blood serum, clot, and urine of normal subjects and three groups of occupationally exposed persons. The thorium concentrations in the blood serum, clot, and urine samples of the exposed groups were distinctly higher than those of the other study groups and were found to increase with increasing occupational length of the persons. Daily urinary excretion is correlated with serum thorium burden and it is estimated that the daily excreted thorium is about 15% of the thorium in the serum pool.