THE PLUTONIUM CONTENT OF HUMAN FETAL TISSUE AND IMPLICATIONS FOR FETAL DOSE

Measurements have been made of plutonium concentrations in human fetal tissues received from second trimester terminations carried out in we st Cumbria and Oxfordshire, using standard chemical techniques and alp ha or mass spectrometry. Fetal tissue concentrations of a few tens of muBq.kg-1 were measured; placental concentrations were of the same ord er of magnitude. These concentrations have been compared with an estim ated average maternal concentration of 0.3 mBq.kg-1, indicating no con centration of this element in the fetus, relative to the mother. The m easured plutonium concentrations have also been compared with those of naturally occurring radionuclides, in particular 210Po, determined by other workers at NRPB in a complementary study. The implication of th ese measured plutonium concentrations for radiation dose, is that expo sure of the human fetus to environmental levels of plutonium results i n an equivalent dose to the fetus during pregnancy of less than 0.02 m uSv. In addition, the risk of detriment from plutonium is considerably lower than for the naturally occurring radionuclide 210Po.