Deposition and retention of plutonium in the United States general population

Since 1959, a Los Alamos National Laboratory study has analyzed over 5000 tissues from 1100 individuals of the nonoccupationally exposed general population for fallout plutonium. These data have been useful in determining the tissue distributions and the annual baseline levels of environmental plutonium in the United States population. The effects of age, sex, date of death, cause of death and geographic location of resididence on the observed plutonium deposition have been evaluated. Because of the difference in biological turnover times of plutonium in the various organs of the body and the changing concentrations of plutonium in the atmosphere, the plutonium concentration ratios between tissues have changed as a function of time. However, our data indicate that over the past 10 years, the highest concentrations in the general population are found in the tracheobronchial lymph nodes and the liver and the lowest concentrations are in the spleen, gonads and kidney. The median body burdens of plutonium in the US population are estimated to have reached 12 pCi during the 1960's and have declined to about 2 pCi in 1977. Large errors in estimated skeletal burdens of plutonium may exist because of small specimen sample sizes and a lack of knowledge concerning the relative distribution of plutonium among the various bones of the human body