SOFT-TISSUE CONCENTRATIONS OF PLUTONIUM AND AMERICIUM IN OCCUPATIONALLY-EXPOSED HUMANS

Human tissues, obtained at autopsy from 82 volunteer donors with a his tory of occupational exposure, were analyzed for Pu-238, Pu-239+240, a nd Am-241 by chemical separation and subsequent alpha spectrometry. Co ncentrations of these actinide nuclides in soft tissues (testes, thyro id gland, spleen, kidneys, heart, and skeletal muscle) were compared t o those of the livers in the same subjects. Tissue:liver concentration ratios were essentially constant over a wide range of liver concentra tions. The spleen had consistently high actinide concentrations relati ve to liver; however, the heart had the greatest concentration ratio f or Am-241. Testes had relatively high concentration ratios of the plut onium nuclides but low concentrations of Am-241. Skeletal muscle had l ow concentrations of plutonium relative to liver but high concentratio ns of Am-241. In the tissues studied, concentration ratios of Am-241 w ere greater than those of the plutonium nuclides, most likely a result of more rapid excretion of that nuclide than the plutonium nuclides b y the liver.