Potential Health Effects of Man-Made Actinides Compared with Natural Radionuclides

Alpha emitters within the body are known to produce both bronchogenic carcinoma (lung cancer) and osteosarcoma (bone cancer). The alpha dose from naturally occurring radionuclides to these critical sites is compared with that which might be expected from the alpha emitters produced in nuclear power reactors (plutonium, americium and curium). A background dose rate of about 9500 mrad to cells in bronchial epithelium and 100 mrad to cells on bone surfaces for a 50 year exposure is estimated for the total of all the natural radionuclides. About 0.25 and 2 mrad respectively are estimated for a 50 year exposure to the man-made actinides when soil is contaminated to the same level as is found for the natural actinides uranium and thorium (about 1 pCi/g). Since the potential for cancer induction ought to be related to alpha dose, contamination of the environment with man-made alpha-emitting actinides can be evaluated on this basis.