Population dose commitment associated with various radionuclides in foods

The radionuclides in foods monitoring program initiated by the Food and Drug Administration in 1973 was expanded in 1975 to include the analysis for hydrogen-3 in selected foods originating from the vicinity of nuclear power stations. Also, in 1975 the analysis for radium-226 was initiated in food samples from areas adjacent to the phosphate mines in Florida. In October 1976 a special survey of milk was performed to determine the levels of fission product contamination from the fallout produced by the detonation of a nuclear device by the People's Republic of China. Results from the analysis of strontium-90 and cesium-137 in the general foods survey for the years 1973 through 1977 indicated intake levels well within range I of the Radiation Protection Guides (RPG) [FRC 1: Range I at 0.1xRPG dose, periodic surveillance; Range II at the RPG dose, quantitative surveillance and routine control; Range III 10xRPG dose, evaluation and additional controls]. The levels of hydrogen-3 in foods from nuclear power station areas were slightly above the tritium background. The radium-226 levels in foods from Florida phosphate mining areas were about double that of the controls. In both cases, however, the radium-226 intake from the total diet was in range II of the RPGs. The iodine-131 levels in the special milk survey in HEW regions I and III were in range III of the RPGs. The levels of barium-lanthanum-140, cesium-137 and strontium-89-90 were all within range I. The clearance half-time from milk for these radionuclides was about 5, 7 and 9 days respectively. (author)