WORLDWIDE EFFECTS OF ATOMIC WEAPONS
BIOMEDICAL CONSIDERATIONS
cortex, is probably quite inactive and the calcium and strontium that reside
there are probably turned over in negligible quantities. It is this aspect of
bone metabolism that renders the quantitative considerations of most
recent tracer work inapplicable to the problem we are considering. The
tracer experiments that have been reported are dealing with a relatively
high concentration of strontium deposited in the bone and are followed
for short periods of time. Thus, in absolute terms, the bulk of the material
of cell division. In fact, a direct comparison between the effects on adults
42
is followed while it is present in the “high turnover’ structures and is not
a true quantitative picture for considering the same amount of material
deposited largely in the “low turnover” portions of mineralized bone. An
experiment reported by Pecher’ supports this contention. He injected
radioactive calcium and radioactive strontium intravenously into mice and
after 24 hr he recovered 58 per cent of the calcium and 33 per cent of the
strontium. However, when he reduced the amountof strontium injected,
43
and the effects on growing children presents a high degree of quantitative
uncertainty at this time.
MAXIMUM PERMISSIBLE BODY BURDEN
FOR STRONTIUM 90
This study is attempting to define the hazard involved relative to the
production of Sr°° by atomic bombs. In order to provide a reference standatd for quantitative comparisons and evaluations of risk, it is suggested
that the maximum permissible body concentration of 1 pc (i.e., 5 X 10°
wg) of Sr°° as established by the International Commission on Radiological
Protection (1950) be used.
Anycalculations referring to the number of bombs exploded, the fallout
problem, etc., may then be extrapolated to this reference point. In this
manner we may then estimate, for a given set of conditions, the number
of people who have been brought to this level. Or, alternatively, we can.
estimate the percentage ofthis level to which a!! people at risk have been
brought.
the recovery percentage more closely approximated the calcium values.
Thus, we are probably further supported when we insist that at the low
levels of natural strontium intake we assume that calcium and strontium
will behave quantitatively in the same way. This supports the use of the
calcium and strontium deposition graphs described earlier.
This quantitative behavioral difference at different ranges of concentration again points out the inapplicability of the tracer experiments being
sible body burden) has important implications relative to the amount of
Sr’ one can calculate as being nonhazardous when released. The dependa-
also brings to mind an important quantitative aspect relative to the mass
matter of vital concern in any quantitative consideration regarding the
release of Sr°° into the earth’s atmosphere. A few remarksrelating to how
reported in the literature.
This brief discussion of the deposition of calcium and strontium in bone
of tissue at risk. If we are discussing the gradual accumulation of a per-
This figure of 1 pc, or 5 X 10° pg, of Sr°° (as the maximum permis-
bility of this standard in predicting what it is supposed to predict is a
missible body concentration over the growth years, we can safely assume
this standard came into being and to some of the limitations involved
wouldseem to be in order.
if we are discussing the accumulation of radioactivity in adults, a sraaller
in man. It has, therefore, been necessary to compare the effects of Sr°° in
that the total mass of the skeleton will be uniformly exposed. However,
mass of tissue is involved, probably on the order of one-tenth of thetotal
skeleton. Other factors also enter into consideration. The 10 per cent of
the skeleton involved in the adult 1s in the region of high turnover with
regard to dynamic equilibrium, and retention may be quantitatively different over a period of years.when compared with that in a young growing
person. On a comparative basis we must also bear in mind that young
growing tissue is more radiosensitive than adult tissue having lower rates
Thereis no direct experimental evidence that Sr°° is a carcinogenic agent
animals with those of radium and then to estimate the equivalent response
in man from the known radium effects in man. The generally accepted
maximum permissiple amount or radium Tinea Mm the Motta SReTeTOT fs
0.1 ug, and the St”® value given above is supposed to be equivalentto this.
(This method of approach was accepted for the bone-seeking elements in
preference to the calculation in terms of a permissible amountof radiation
equivalent to 0.3 r/week to the critical tissues. Because of the distribution