Deposition of Strontium-90 Through October 1958
It is estimated that the global deposition of strontium-90 increased from 1.9 to 2.6 megacuries during the period from June 1957 to October 1958. During this time the stratospheric reservoir of strontium-90 increased from l.4 to 4.3 megacuries. Approximately 90 percent of the deposition of debris now stored in the stratosphere will have occurred by 1970. In 1958, the strontium-90 content of powdered milk in the New York area averaged 5.9 micromicrocuries per gram of calcium in comparison with 3.9 micromicrocuries per gram of calcium for the previous year. For this region of the country, the strontium-90 content of milk appears to be increasing in proportion to the strontium-90 content of the soils from which the cows derive their forage. The upper limit of foreseeable contamination in milk can be estimated by assuming that this proportionality will continue until all of the strontium-90 has been deposited from the upper atmosphere. This procedure should yield estimates which tend to err on the side of safety. In this manner, it is estimated that the maximum foreseeable sustained level of milk contamination in the New York area is 11 micromicrocuries per gram of calcium. A child deriving fts calcium from dairy sources may be expected to develop a skeleton having 5.5 micromicrocuries per gram of calcium. This estimate is double that made in June 1957 and reflects the increased stratospheric inventory due to U.S.S.R. detonations in 1958. The radiological dose to the skeleton from natural sources such as cosmic rays, radium, potassium, and so forth, is approximately 125 milligrams per year. A skeletal burden of 5.5 micromicrocuries of strontium-90 per gram of calcium will deliver a dose of approximately 5.5 milligrams per year to the bone marrow. The maximum foreseeable dose from strontium-90 in the New York area is thereby estimated to be about 5 percent of the dose due to natural radioactivity.
- Research Organization:
- U.S. Atomic Energy Commission, New York
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-13-018022
- OSTI ID:
- 4261959
- Journal Information:
- Journal of Occupational and Environmental Medicine, Vol. 1, Issue 12; Other Information: Orig. Receipt Date: 31-DEC-59; ISSN 1076-2752
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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Related Subjects
ABSORPTION
ATMOSPHERE
BACKGROUND
BODY
BONE MARROW
BONES
CALCIUM
CATTLE
CONTAMINATION
COSMIC RADIATION
FOOD
MAN
MILK
NUCLEAR EXPLOSIONS
POTASSIUM
POWDERS
RADIATION DOSES
RADIOACTIVITY
RADIUM
SOILS
STRATOSPHERE
STRONTIUM 90