SESSION IV DISCUSSION 899 HARDY: Weknow that the Sr levelinthe diet was also increasing, but 37cs was increasing at a faster rate and was moreclearly reflected in the excretion values than was “Sr. VAN MIDDLESWORTH: I would like to ask Dr. Strgmme about something he had in a reprint he showed me but did not include in his paper regarding the different muscles of the body containing widely varying concentrations of cesium. Can you comment on this large difference? I wonder if the muscle cesium/potassium ratio was different. How do you account for these phenomena? STROMME: We have studied only one man so far for the paper I showed you. However, I know that reindeer have been studied very well in Norway, cesium than and it seems that the active muscles contain much more the inactive muscles. I don’t know if this is true for potassium. The material was too scarce for potassium studies. HARDY: Mr. Brar, can you or Dr. Gustafson give any reason for the increase in the '°"Cs bone levels after 20 years of age? BRAR: No, 1 don’t think we can. We are just trying to find what is in the bone. We don’t know why it is there. People have not suspected there would be any cesium in the bone at all, but rather that all of it would be in tissue. However, Japanese investigators have found some, and we also have found some. One of the speakers this morning mentioned that '°"Cs uptake from the soil was quite small, but still one finds quite a bit of this nuclide in grains, especially in those which are contained in pods, such as soybeans. Is there any possibility that cesium is absorbed through the leaves or stalks? Could someone answer that? WARD: I am not a plant physiologist, but the answer is that cesium is very mobile in the plant once it has been absorbed. Presumably absorption occurs largely through foliar absorption. The cesium gets into the plant system and then could be transferred to the seeds quite readily. BENINSON: On the same problem, I think that most of the data show that cesium levels depend mainly on the current rate of fallout. However, Dr. Frederickson and others claim that for some soils the soil-uptake component is important. Probably a good relation can be found which takes into account both the current year’s fallout and the average of the fallout for the past two years. With this sort of equation it seems possible to fit the actual measured milk data. However, from experimental work on contaminated soil and in connection with waste disposal, it would seem that no cesium or, at most, a very small fraction would be taken up from soil.

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