Sr® content of their bones will be higher than present-day adults, because their skeletons will reflect the contamination levels that have existed throughout their entire lifetime. It should be noted also that the bones of stillborn infants, or those that die at a very early age, contain only the amount of Sr® that is supplied by the mother through the placenta. Ex- amination of the data reveals that the Sr®*level in the skeleton of stillborns is lower than that in the bones of children aged 1 to 5, for example. It seems evident that the Sr® level in skeletons of stillborn children should not be considered as a reliable index of the uptake from the contaminated environment. 80 NUMBER OF SAMPLES 7OrF I AVERAGE °F ITIL | = 30 20 oO } pet TT yo O 02 04 06 O08 10 12 44 16 18 20 22.24.26 28 30 32 34 36 38 40 42 44 46 48 50 52 Sr90/G Ca, pyc (a) g _ AVERAGE a = aT uw ob oO ti afr s 2h = zd - 3 0 BosTON (| SWISS - 1A 02 04 06 08 AUDA | 10 1.21416 48 20 | 3.0 Sr30/G Ca, pyc ; 40 50 (b) Fig. 13—Histogram of Sr®® concentration in bones. a, Adult bones, representing world, 1955-1956. b, Bones from children, 1956. c. Sr?" in Teeth. It would be desirable to use humanteeth as a substitute for bone sam- ples, particularly for younger children from whom deciduous teeth are readily available. Some work has been done on the analysis of teeth, but more data are required before a decision can be made that teeth are a satisfactory substitute. The available results are shown in Table 47. 4.5 WHOLE-BODY MEASUREMENTS OF Cs}? It is possible to measure the Cs!*" content of the human body in vivo. The Cs'*" level in man is the resultant of several portions of his diet, including milk, meat, vegetables, and possibly drinking water, and should be relatively stable over short periods of time. 62