Abstract
This report presents the result on the measurement of plutonium in Japanese human bone samples collected in four cities. Those measurement was done in connection with the nuclear explosion tests conducted since 1962.
The results show that the concentration of plutonium in human bone has increased yearly from 1962 through 1971, and the average concentration in 1971 was 4 × 10-15Ci per one gram of bone. Any difference due to the sampling place, sex or age has not been detected in the plutonium concentration in bone. It is of significance to note that the transfer of plutonium to fetus was recognized. The amount of plutonium deposited in bone showed a closer relation to the concentration of plutonium in air than in diet. It is estimated by using the equation of ICRP (1959) that the radiation dose delivered to bone is 16.3 mrem/year at the radioactivity level in 1971.
