relatively large ranges in values were found for the individual isotopes
in the plants and animals.
Any conclusions, therefore, must be of only
the most tentative and generalized nature.
.
4
The data do suggest that in terms of strontiun-90, the isotope
of principal concern, this activity built up in the plant life over ‘the
first year after fallout and then started
decreasing
slowly.
By using
very rough approximation, and extrapolations, the data suggest that if
plant life had been growing in the area of highest contamination it might
have contained 10-30 microcuries of strontium-90 per kilogram of calciun,
at one year.
higher.
The corresponding values for the soils are several times
If an assumption is made that there is a discriminatory factor
of about four for the Sr/Ca ratio in plants versus bones, the above data
suggest possible levels of strontium-90 in the bones of animals from
continuous consumption of this food of a few to several microcuries.
of strontium-90 per kiiogram of calcium.
The maximum permissible body
burden for adult atomic energy workers is one microcurie of strontiun-
990 per kilogram of calcium.
There is some confirmatory evidence for this crude evaluation.
A variety of native animals were left on the Island of Rongelap after
the fallout in March 1954.
serially in time.
Tney have been collectad and sacrificed
Even after two years of continuous occupancy it was
reported that there were no pathological changes that could be ascribed
to radiation.2*
Their bones showed from about a one-tenth to a few tenths
of a microcurie of strontium-90 per kilogram of calcium.
Since the areas
of highest contamination were about 12-14 times greater than Rongelap,
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