212 ignored. . DASA 2019-2 But iron goes to very small volumes of tissue. Specifically, it tends to concentrate in little globules and you get a very high dose there because essentially all of the range of the iron-55 electron is comparable with the diameter of the globuie. MILLET: May Lask if the unexposed population showed chromo- somal changes, too? CONARD: They showed some peculiar chromosomal changes that we haven't been able to understand yet, chromosomal breakages. They show about as many breakages of chromosomes as do the exposed people. But I was referring to the more specific radiationinduced types of aberrations, such as dicentrics and ring forms that occurred. AYRES: May I ask about the zinc? is it stored inthe body? for something else? How is that taken up and where Is it taken up as zinc or is it a surrogate CONARD: I really don't know. fairly well distributed, as I recall. I know it gets into the body and is LANGHAM: It's concentrated in the epithelial tissues, is very high, the skin is high. CONARD: The hair Theprostate I believe is fairly high. LANGHAM: The prostate and pancreas. greatest amount is in the skin and hair. Percentage wise, the BRUES: It looked to me as if the cesium levels were remaining rather constant in these people. I think that's remarkable. It turns over with a half-time of three months or so in man. So they must be in essentially 4 closed environment without cesium drifting or blow- ing out of it. CONARD: That's so. And I think, as Lauren pointed out, the fact that this raaterial is sticking in the upper layer of the soil and not being dispersed, being diluted in soil, so to speak, means that fora long tirme we'll have levels that can be detectable. * *Since this symposium, results on the latest radiochemical urine analyses (March 1967 urines) reveal that the excretion of these radionuclides