FACTORS INFLUENCING THE BIOLOGICAL AVAILABILITY OF FALLOUT RADIONUCLIDES FOR ANIMALS AND MAN
Biological availability of radioiodine and radiostrontium is considered broadly in terms of relations to radiation exposure. The most important source of I/sup 131/ in human diet is milk. Time at which maximum I/sup 131/ concentration appears in milk is dependent upon ingestion patterns of the animals serving as the milk source andd hence, upon condition of the pasture. Usually found in the form of iodide, I/sup 131/ levels in cow's milk are 1% of a daily ingested dose per liter of milk at steady state and about 8% of a single dose in the total milk. Corresponding values for the goat are 40% of a single dose in the total riilk and 65% of a daily ingested dose per liter; the very high variability is accounted for by extremes in the levels of milk production of the goats studied. Many chemicals such as iodide or perchlorate when fed to the core will reduce I/sup 131/ levels in milk. However, these chemicals themselves are secreted into milk and may have an effect on the consumer. As a combined effect of thyroid weight and fresh-milk intake, 6 months to 2-year-old children would be expected to have the highest exposure. The body burden of Sr/sup 90/ is governed primarily by the Sr/sup 90// CA ratio of the total diet and the comparative retention of these two substances in the body. Plant foods and dairy products are the maln contributors of Sr/sup 90/ to the human diet, dairy products generally having a lower Sr/sup 90//Ca ratio. From a practical standpoint, the greater the proportion of dietary calcium coming from dairy products as compared to plant foods, the lower will be the Sr/up 90//Ca ratio of the diet. Reduction of Sr/sup 90/ levels in milk by dietary supplementation of stable calcium is possible but for a number of reasons, is not feasible. (H.M.G.)
- Research Organization:
- Cornell Univ., Ithaca, N.Y.
- NSA Number:
- NSA-18-003604
- OSTI ID:
- 4139539
- Journal Information:
- Federation Proc., Journal Name: Federation Proc. Vol. Vol: 22
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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