Reprinted from ScIENCE, August 3, 1958, Vol. 128, No. 3318, pages 256-257.
Common Strontium Content
of the Human Skleton
The geochemica and biogeochemical
behavior of the dement strontium is
important in undestanding the movement of fission-procict strontium-90 into
man (7). Several investigators (2, 3)
have analyzed hunan bone from different locations for srontium, The availability of a large collection of bones
from the study of torld-wide fallout of
strontium-90 made convenient the examination of this frameter in greater
detail. This report ¢) is concerned with
(i) the distributionof strontium among
the different bone in an individual
skeleton, (ii) the «stribution of strontium in the populaion of a single city,
and (iii) the extesion of information
on geographical vziation. Samples consisted of a variety>f bones from eleven
individuals, wholekeleton ash from 133
NewYork City caavers, and composites
from 16 localiti, each representing
equal weights of tne ash from 4 to 38
individuals.
The analyses we performed by an
emission spectrognhic technique modified from that o'Turekian and Kulp
(2), The standan used to define the
working curves we actual samples of
bone ash which #re analyzed by the
isotope dilution ethod (accurate to
within 5 percent) \ll samples were run
in duplicate and-e reported as parts
of strontium per rion. The reproeducibility of these aryses is estimated to
be about + 10 perat.
The average strtium content of ad-
ditional samples fn previously investi-
gated areas (2) waound to be about 30
percent lower. In cer to check this discrepancy, some ofte original samples
were reanalyzed the present method.
The new analysesere also about 30
percent lower m ch case. Synthetic
standard: similar those used by Tu-
rekian and Kulp’) were analyzed,
using the present sking curve defined
by isotope dilution alyses of bone ash,
The results indicathat a matrix difference between bs and chemically
precipitated phosp! is responsible for
the higher values reted in the carher
work (2
In view this observation,
the samples of Turn and Kulp were
composited by ety and redeter-
mined.
The distribution of commenstrontium
among the different bones of individuals
was examined by analyzing the femur,
tibia, fibula, humerus, u!na, radius, hand
or foot bones, skull, pelvis-sternum, vertebrae, ribs, clavicle, scapula, and kneeelbow from eleven skeletons (5). Although the average strontium content of
the whole skeleton varied by a factor of
3 among these individuals, there was no
systematic difference in strontium content between any two bones of the body
outside of the experimental error (stand-
Table 1. Worid survey of common strontium in human bone.
:
Location
Boston
Boston
Boston
New York
Houston
Houston
vo. of
amples
samp
Sr in bone ash
ppm
North America
37
38
62*
134*
14+
12
Av
101
109
117
162
125
190)
162
152
~
105
Denver
337
203
203
Vancouver
Vancouver
San Juan
17}
12
5+
164
117
i79
14
179
Guatemala
29
156
156
Recife
South America
344
344
Guayaquil
17
oT
i79
179
Cordoba
18
160
160
Santiago
37t
160)
160
187
Santiago
a4
160
Caracas
377
187
West Germany
Copenhagen
Copenhagen
Europe
307
137
137
2T
4
242
256
253
140
Zurich
ly
140)
Rome
OF
168
Rome
London
London
10
4y
21
Ava
Tokyo
Tokyo
Tokyo
‘Taiwan
36
21%
at
19+
India
ait
Taiwan
India
Durban
Liberia
World av
6
12
Africa
13
1
258
187
136
206
199
23
191
179
176
206
160
ard deviation of 10 percent). Thus a
single bone can give a valid estimate of
the common strontium content of the
body at this level of certainty. This
would also be the case for strontium-90
distribution if a population ingested a
diet
.
18;
.
“14
187
194
324
195
324
172
* Samples run individually, ¢ Samples reported by
Turekian and Kulp (2) rerun as composites.
a
constant
Sr®°/Ca_
ratio
uals.
The histogram (Fig. 1) of the stron-
tium concentration in 133 individuals
(whole skeleton ash} from New York
City shows a nearly normal distribution
with a standard deviation that is only
about +32 percent of the mean of 162
parts per million by weight. The narrow spread reflects the averaging of food
sources In a city environment,
The data on the concentration of
strontium in human bone in various geo-
graphical localities are summarized in
Table 1. To show that the use of com-
posite samples is valid, the samples from
Boston and Tokyo were run individually,
and then equal weights of bone ash were
combined into composite samples. There
appear to be small but significant differences from one locality to the next,
The average for any given locality falls
within a factor of 2 of the mean of the
data (172 ppm). Recent work by Sow-
den and Sutch (6) on a limited number
of samples from England analyzed by
neutron activation gives results which
are consistent within the experimental]
and natural variation of those reported
here. Their work shows a Jower strontium concentration in young children.
This is expected as a result of fetal discrimination against strontium (7). An
examination of the present analyses
shows that for adults there is no age
effect,
The average world-wide value of
(%Sr)/(%Ca) x 10% in human bone
derived from Table 1 is 0.45+0.1. The
value
206
with
throughout the lifetime of the individ-
(%Sr/%Ca} x 10%
in
average
rock or soil is 7+ 1 (8). The discrimination factor between soi! and skeleton
for the strontium/calcium ratio is therefore 1522. The experimentally determined discrimination factor for strontium/caleium between soil and plant is
about unity (9), between plant and milk,
about 7 (10), and between milk or vegetation and human boneit is about 4 (73.
Thus, if in the average urban world
population, half of the calcium in the
diet comes from milk, and half from
poe ARCHIVES