Strontium-90 and the Restlessness of Nature
In the spring of 1953, officials from the U.S. Atomic Energy Commission (AEC), military officers, and scientists affiliated with the RAND Corporation met in Santa Monica, California. They confronted a conundrum. Radioactive debris from Ivy Mike, the world’s first thermonuclear detonation, was missing. Ten megatons (10,000 kilotons) of explosive yield swept over Enewetak and outlying atolls in the Marshall Islands the previous November but little of it was detected by monitoring stations across the Pacific. Those assembled speculated it either came down where there were no monitoring stations or ascended through the troposphere and into the stratosphere–something which had never occurred before.
Of particular concern was strontium-90. With a half-life of 29 years, it constituted a serious and persistent radiological hazard. It is a “bone seeker.” Chemically similar to calcium, radiostrontium locates in deciduous (baby) teeth and bone upon ingestion, typically through contaminated milk. It can contribute to leukemia and bone cancer, in time. However, the esteemed physicist Willard Libby suggested to those assembled that debris was mixing in the stratosphere and when it came back to earth–which he surmised could be as long as 10 years–it would undergo radioactive decay and it was unlikely there would be terrestrial hotspots. That is, it would remain sequestered above the troposphere for some time and exhibit uniform re-deposition over the earth’s surface when it did come down. Nature provided an advantageous buffer from the hazards of strontium-90.
Libby was right. The fallout from Ivy Mike ascended into the stratosphere. He was wrong about everything else. Over the course of the 1950s, he was forced to continually revise downward the stratospheric sequestration of radioactive debris: from 10 years to 7, to 5, to less than 5, to less than a year depending upon how high in the stratosphere it ascended. In 1960, the same year he received the Nobel Prize, he co-authored an academic journal article indicating stratospheric holdup could be as little as 8 months for polar debris and less than 5 years at the equator. In 1968 Libby co-authored a study illustrating a stratospheric residence time of around 1.6 years. Further, it came down more heavily in the northern hemisphere in a latitudinal band encompassing the United States, Europe, and Russia.
During the era of atmospheric atomic testing, from 1945-1962, AEC and military officials as well as scientists working under contract with the AEC often defaulted to naïve and self-serving assumptions when confronted with the fallout of radionuclides upon the public. Strontium-90 traversing through ecological, corporeal, political, and cultural pathways illustrated the contradictions of brilliant, indeed noble-prize winning, science and technology. Moreover, even as each detonation in the south Pacific directly threatened the residents of the Marshall Islands, the transition from fission-fueled devices to hydrogen “super bombs,” ejecting fallout into the stratosphere, also constituted a hazard on the U.S. mainland, particularly in those areas experiencing consistent rainfall.
Radiostrontium highlights the agency of nature and restless, endemically chaotic, meteorological dynamics impossible to master or scarcely anticipate. Fallout moved in different directions, at different altitudes, and all at a different tempo. It migrated further than anticipated and arrived in a more intense state. It came down to earth capriciously and migrated through the food chain with surprising rapidity.
In 1957 the Greater St. Louis Citizens’ Committee for Nuclear Information (CNI) began collecting baby teeth for radiological analysis. It was a means of obtaining data on strontium-90 uptake that the atomic-industrial complex could not contain, control, or classify.
CNI was a consortium of faculty from Saint Louis University, Washington University, and community members. The biologist Barry Commoner was a founding participant who pushed forward the organization’s objectives before the public while volunteers cataloged and prepared baby teeth for analysis. Many were mothers concerned for the health of their children. CNI produced brochures, a newsletter, and reached out to St. Louis area schools, libraries, Cub Scout troops, dentist offices, and civic organizations large and small. Children who mailed in a tooth received a button declaring “I Gave My Tooth to Science,” and by 1959 CNI was receiving hundreds of teeth each week. Over 320,000 teeth were collected before the project ended in 1970.
Dr. Louise Reiss served as the project director from 1959-1961 and published the first results in the journal Science in 1961. Children born in 1951 and 1952 illustrated stable strontium-90 but the levels increased in 1953 and again in 1954 consistent with increasingly high yield detonations by the United States and the Soviet Union. Subsequent research documented a 30-fold increase in strontium-90 levels between 1951-1963, in tandem with the increasing pace of the global arms race.
Few parents forget the drama of coaxing loose a tooth from their child’s mouth, but by the late 1950s, this right-of-passage was of scientific and political consequence. Herein lay a record of the geopolitical posturing of the U.S. and the Soviet Union in the mouths of babes. The levels of strontium-90 documented were not known to be hazardous, but neither was it clear they were benign as children aged. What was clear is the increasing presence of strontium-90 suggested to many that the debate over atmospheric testing could no longer be dominated by a select few from within or tied to the AEC.
The baby tooth survey made visible a contaminant composed of energetic matter. And as a distinctive marker of the atomic age, it was drifting far and wide. Geography and even social class no longer offered sanctuary from American militarism. “The Atomic Energy Commission turned me into an environmentalist,” Barry Commoner remarked.
In September of 1962, Silent Spring arrived on bookshelves. Examining the proliferation of pesticides, and DDT in particular, Rachel Carson highlighted fallout–both radioactive and chemical–in describing the indiscriminate imposition of harmful substances upon the public; substances with deleterious effects unbounded across space and persisting tenaciously over time. In a letter penned in 1958, Carson confided:
I suppose my thinking began to be affected soon after atomic science was firmly established. Some of the thoughts that came were so unattractive to me that I rejected them completely, for the old ideas die hard, especially when they are emotionally as well as intellectually dear to one. It was pleasant to believe, for example, that much of Nature was forever beyond the tempering reach of man—he might level the forests and dam the streams, but the clouds and the rain and the wind were God’s.
In the atomic age the clouds, the rain, and the wind serve as transit for radioactive substances evoking injury in a widespread, crescive manner.
Citizen-scientist activism contributed to the Limited Test Ban Treaty of 1963 banning open-air detonations by the United States, United Kingdom, and the Soviet Union. Detonations went underground, significantly reducing the threat of strontium-90 contamination. But the past is reflected in–and constitutive of–the present. Strontium-90 falling out upon the public portends lessons applicable to a variety of contemporary issues of concern. Of particular importance is the availability of information; data from which to assess the conduct of powerful organizations in society. Absent such information, organizational actors are apt to default to self-serving assumptions that amplify the risks to public health.
For more information, see:
Report detailing the Santa Monica conference: Atomic Energy Commission, “Rand Sunshine Project,” Division of Biology and Medicine, 30 December 1953.
Libby’s successive revisions to the stratospheric holdup of strontium-90 and uniform redeposition: W.F. Libby and C.E. Palmer, “Stratospheric Mixing from Radioactive Fallout,” Journal of Geophysical Research 65, no. 10 (1960): 3307-3317; P. Fabian, W.F. Libby, and C.E. Palmer, “Stratospheric Residence Time and Interhemispheric Mixing of Strontium 90 from Fallout in Rain,” Journal of Geophysical Research 73, no. 12 (1968): 3611-3616.
For the results of the baby tooth survey see: William Krasner, “Baby Tooth Survey: First Results,” Environment 55, no. (1961): 18-24; Louise Zibold Reiss, “Strontium-90 Absorption in Deciduous Teeth,” Science 134, no. 3491 (1961): 1669-1673; Caroline Jack and Stephanie Steinhardt, “Atomic Anxiety and the Tooth Fairy: Citizen Science in the Midcentury Midwest,” The Appendix 2, no. 4 (2014).
The Barry Commoner quote is from a 1993 interview in the Chicago Tribune and referenced: Daniel Lewis, “Saw an Earth at Risk and Let the World Know,” New York Times, October 2, 2012, A1.
Carson’s quote is taken from: Letter from Rachel Carson to Dorothy Freeman dated February 1, 1958, Pp. 406-408 in Letters of the Century: America 1900-1999, edited by Lisa Grunwald and Stephen J. Adler (NY: The Dial Press, 1999).
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