Word: strontium
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Dates: during 1950-1959
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...daily press reports have indicated that radioactive strontium 90 from the fallout of thermonuclear explosions is nothing to worry about. Japanese scientists do not agree. On April 8 scientists working under Japan's Atomic Energy Commission will present a report to the United Nations Radiation Committee. Its gist: strontium 90 should be studied carefully, and much more must be known about it before it can be written off as harmless to the human species...
Walter Selove, professor of Physics at the University of Pennsylvania and formerly assistant professor of Physics here, took a rather different viewpoint of the situation. He pointed out that it is virtually impossible to determine what may be reasonably called a "permissible level" of radioactive strontium 90 in the body...
Selove also stated that there was a tremendous variation in the amount of strontium 90 found in the soil. He said that the concentration depended on the amount of calcium in a certain area--there have been variations from the mean of as much as 5000 percent because of calcium concentration--and also that the amount of strontium taken into an individual's body depends on the form in which it is ingested...
Most of the strontium 90 created by past bomb tests is still in the stratosphere or in the soil, but it will tend to move for years into human bones. If no more large tests are made, the Columbia men figure, the average human bone should contain, by 1970, about 1.3 micromicrocuries of strontium 90 per gram of calcium. This is eleven times the present amount...
...Columbia men are concerned about such individuals as the Vancouver man who have a lot more strontium 90 than the average, and about people who get most of their calcium from vegetables that were grown in calcium-deficient soil. Such people may come much closer to the "permissible" level. The permissible level itself is still considered debatable. It was derived principally from a small amount of experience with the cancer-causing effects of radium in the bones; at that time no strontium 90 existed in the world. When more is known, the permissible level for strontium 90 may have...