that this be considered as well as the value in terms of micromicrocuries of Sr® per gram of
calcium, since a high value for the latter is less important if the over-all concentration is low.
e. Diet Sampling Surveys Conducted Outside the United States. A number of diet surveys
are being undertaken throughout the world to study the nutrition of the countries concerned.
Some of the samples taken for this purpose have been made available for sr® analysis. In addition, certain food sampling has been carried out in South America under the direction of
Dr. Paul Pearson of the Division of Biology and Medicine, AEC. The results of these analyses
are given in Table 38.
f. Sr®° in Miscellaneous Vegetation and Herbage.
The results of a numberof miscel-
laneous samples of vegetation and herbage are given in Table 39. These data are reported for
completeness and are not directly connected with any of the monitoring or experimental
programs.
4.3
SrIN URINE
Urine sampling is a technique widely used in the field of industrial hygiene to measure
exposure of workers to toxic materials. The variation in excretion rates among individuals
exposed to the same level, however, makes the urine results very difficult to interpret. Colonel
James Hartgering of the Walter Reed Army Hospital reported a series of results at the Congressional Hearings in 1957. A few other data are given in Table 40.
4.4
BONE
In following calcium through metabolic processes, sr®*shows highest concentration in bone
when comparedto other tissue. The various factors in the uptake of Sr® and the Sr/Ca discrimination are being studied. In addition, it is desirable to have a monitoring program to
follow the concentrations of Sr®® in various bone materials as a function of time.
;
Measurements have been carried out on both animal bone and human bone. Animal bone
invariably shows high Sr* concentrations when compared to human bone from the same area.
One factor causing this higher concentration is the amount of Sr® deposited on leaf surfaces.
This leaf deposit is eaten by the animal, whereas a large portion of the human diet consists of
foods of animal origin, which contain lower concentrations of Sr®, and well-washed and otherwise prepared vegetables.
a. Sr*? in Miscellaneous Animal Bone.
In addition to certain specific studies of animal
bone (see Secs. 5.1 and 5.5), there have been a number of miscellaneous animal bone samples
analyzed. These are tabulated according to the laboratory responsible for the analyses, but
they are not otherwise grouped.
Table 41 gives the HASL data; Table 42 gives the data from the University of Chicago, and
Table 43 gives the data from the Lamont Geological Observatory.
The levels in the samples reported here may be compared with those reported by the
United Kingdom, which are presented in Part 4 of this report.
b. Sr*? in Human Bone.
The largest group of data on the Sr® content of human bone is
that reported by Dr. Kulp of the Lamont Geological Observatory.” These data have been sum-
marized in the articles cited, but a brief summary is reproduced here in Table 44 and Fig. 13.
A number of samples were analyzed at the University of Chicago, and the results are summarized in Tables 45 and 46. The first table includes infants from the Chicago area, and the
second table summarizes the results on infants from other localities.
The level of Sr® in human bone lags considerably behind the level in the environment. In
other words, man is generally not yet in equilibrium with his environment. The highest
Sr®° values should be found in children that have lived their lives in the period of greatest con-
tamination, i.e., children born in late 1954 or afterward. This is generally reflected in the
data presented for the United States as well as for other countries such as the United Kingdom.
(See Part 4 of this report.)
Adult bone indicates only the turnover of skeletal calcium and contains Sr” at a relatively
low level at the present time. When the children who were born since 1954 become adults, the
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