856
BENINSON, RAMOS, AND TOUZET
Table 5 summarizes the results from bone samples for which a
detailed dietary history could be assembled. Table 6 gives estimates of
the corresponding calcium increments in skeleton between consecutive
average ages of age groups. These values have been computed with the
following information. The calcium content of a newborn child is estiTable 6— CALCIUM INCREMENTS It.
SKELETON CORRESPONDING TO
%0Sr IN BONE AND DIET HISTORY
Age group,
Calcium
Age group,
Calcium
months
content, g
months
content, g
Fetal
0 to 2.1
0 to 6
6 to 12
24
12.3
30.4
30.4
i
12 to 24
6 to 9.5
12 to 18.7
24 to 33.6
39.6
17.7
22.1
21.5
mated to be about 24 g in the Argentine litoral area.'” In addition, published calculations’? show that the calcium increase in the child fits
reasonably well the expression
Calcium retained
= constant
(Calcium ingested) x (weight of child)
A not readily assessed uncertainty is introduced by the calculation
procedure.
The whole question of averaging is debatable. It is felt, however,
that the near constancy of daily intakes and skeletal calcium increase
Supports averaging, assuminglinearity. Detailed tables for the calcium
level in bone for this area are published elsewhere. ’?:®
The *Sr/calcium ratios in children’s bone in the Argentine litoral
area are a little lower than those observed in Australia and less than
one-half of most values found in the northern hemisphere. Dose rates
incurred in bone from this contamination is of the order of 3 mrad per
year.
Stable Strontium
Analysis of stable strontium in bone was made of materials obtained during 1963, including samples for which no diet history could
be satisfactorily assembled. Means and standard errors are compiled
in Table 7. It should be noted that determinations of different bones
from the same child show no significant variations within the skeleton.
Results suggest that stable-strontium/calcium ratios increase slowly
with age, from 0.23 mg/g in fetal bone to about 0.4 mg/g in the third
year of life, the value which is also observed in adults.