Strontium-90 concentration measurements in human bones and teeth in Greece

Strontium-90 concentration was measured in human bones and teeth collected in Greece during the period 1992-1996. One hundred and five bone samples, m ainly cancellous bone, and 108 samples, taken from a total of 896 individua l teeth were processed. Samples were classified according to the age and se x of the donors. Samples were chemically pre-treated according to a special ly devised method to enable extraction of Y-90, at equilibrium with Sr-90 i n the original sample. Subsequently, Y-90 beta activity was measured with a gas proportional counter. Radiostrontium: concentration in bone samples sh owed small variations with respect to age or sex, with an average value of 30 mBq Sr-90/g Ca. However, Sr-90 concentration measurements in teeth demon strated a pronounced structure, which clearly reflects contamination from t he 1960s atmospheric nuclear weapons tests and the more recent Chernobyl ac cident. This difference is attributed to the different histological structu re of skeletal bones and teeth, the later consisting mainly of compact bone . An age-dependent model for radiostrontium concentration in human bones an d teeth is developed which is able to successfully reproduce the experiment al data. Through a fitting process, the model also yielded calcium turnover rates for compact bone, as a function of age, as well as an estimate of ra diostrontium contamination of foodstuffs in Greece for the past four decade s. The results obtained in this study indicate that radiostrontium environm ental contamination which resulted from the atmospheric nuclear weapons tes ts in the 1960s, exceed by far that caused by the Chernobyl accident. (C) 1 999 Elsevier Science B.V. All rights reserved.