| Plutonium from Above-Ground Nuclear Tests in Milk Teeth: Investigation of Placental Transfer in Children Born between 1951 and 1995 in Switzerland Pascal Froidevaux1 and Max Haldimann2 1University Institute of Radiation Physics, University Hospital Center, University of Lausanne, Lausanne, Switzerland; 2Consumer Protection, Chemical Risks, Federal Office of Public Health, Bern, Switzerland Abstract
Background: Occupational risks, the present nuclear threat, and the potential danger associated with nuclear power have raised concerns regarding the metabolism of plutonium in pregnant women. Objective: We measured plutonium levels in the milk teeth of children born between 1951 and 1995 to assess the potential risk that plutonium incorporated by pregnant women might pose to the radiosensitive tissues of the fetus through placenta transfer. Methods: We used milk teeth, whose enamel is formed during pregnancy, to investigate the transfer of plutonium from the mother's blood plasma to the fetus. We measured plutonium using sensitive sector field inductively coupled plasma mass spectrometry techniques. We compared our results with those of a previous study on strontium-90 (90Sr) released into the atmosphere after nuclear bomb tests. Results: Results show that plutonium activity peaks in the milk teeth of children born about 10 years before the highest recorded levels of plutonium fallout. By contrast, 90Sr, which is known to cross the placenta barrier, manifests differently in milk teeth, in accordance with 90Sr fallout deposition as a function of time. Conclusions: These findings demonstrate that plutonium found in milk teeth is caused by fallout that was inhaled around the time the milk teeth were shed and not from any accumulation during pregnancy through placenta transfer. Thus, plutonium may not represent a radiologic risk for the radiosensitive tissues of the fetus. Key words: fetus exposure, milk teeth, nuclear bomb test fallout, placenta transfer, plutonium, plutonium metabolism. Environ Health Perspect 116:1731–1734 (2008) . doi:10.1289/ehp.11358 available via http://dx.doi.org/ [Online 17 September 2008]
Address correspondence to P. Froidevaux, Institute of Radiation Physics, Grand Pré 1, CH-1007 Lausanne, Switzerland. Telephone: 41-21-623-3480. Fax: 41-21-623-3435. E-mail: pascal.froidevaux@chuv.ch We thank J.-J. Geering for the long-term collection of milk teeth and vertebrae in collaboration with dentists and pathologists from different regions of Switzerland. Research funding was provided by the Swiss Federal Office of Public Health (P.F. and M.H.) and the University of Lausanne (P.F.) . The authors declare they have no competing financial interests. Received 12 February 2008 ; accepted 16 September 2008.
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