THE OCCURRENCE OF ANTIMONY-125, EUROPIUM-155, IRON-55,
AND OTHER RADIONUCLIDES IN RONGELAP ATOLL SOIL
INTRODUCTION
Since 1946 the Laboratory of Radiation Biology of the University
of Washington has conducted studies at the Eniwetok Proving Ground
to evaluate the effects of
radioactivity produced by the atomic
tests on aquatic and terrestrial organisms.
studies” 2,3,4,9,6
The results of these
have shown that a definite relationship exists
between the amount and nature of the radioisotopes in the environment
and in the living organisms.
In the present study, detailed analyses
were made of soil samples taken from several locations at Rongelap
Atoll
in July 1957.
The samples were examined for total radioactivity
as well as for isotopic content.
Gamma spectrum curves from the soil samples contained gamma
peaks which indicated the presence of one or more isotopes not previously reported in biological or soil samples from the Marshall Islands.
The gamma energies agreed well with those of Sb 125 and Eu!55, which
are produced in very small amounts in y235 fission (0.023 per cent and
0.031 per cent respectively,
of approximately two years.
samples from
tervals
since
Rongelap
March 26,
Sullivan), 8 and which have half lives
Subsequent analyses of several soil
Atoll which had been
1954,
-l-
showed
the
collected
presence
of
at
inthese