to decline except for small. transitory rises in the next few springs. The annual (1963) national average was ( to come ) "strontium units" in milk. This is less than the 34 "strontium units" predicted and should foretell less in the bones than predicted!-, (In general, predictions in the past of levels of strontium-90 in bones have been too higt.: This is due in part to the selection of data in the upper ranges to avoid underestimations of radiation exposure. Even so, it is remarkable that the observed amounts of strontium-90 in bones have been within about a factor of two of those predicted considering the fact that such predictions require the application of many scientific disciplines - nuclear physics, meteorology, chemistry, plant and animal physiology, etc., ~ often to new situations.) That segment of the U. S. population whose bones will receive the highest radiation dose are children born in 1963 in regions of ‘heavier rainfall. The total radiation exposure - from internally deposited as well as external radionuclides ~ has been predicted to be about 465 milliroentgens (0.465 roentgens) accumulated over a 70 year period! -. (This was based in part on predictions - that now appear to be somewhat too high - of the strontium-90 in the food supply.) Evaluation - The predicted average 70-year radiation dose to the bones of the age group receiving the highest exposure from all past tests - about 465 milliroentgens (0.465 roentgens) - is about five percent of the bone dose received during the same 70 year period from natural background sources. Gy CD a a