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 ” 2,3,4,9,8
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 examinedfor 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 Sp 125 and Eul55, which
are produced in very small amounts in u235 fission (0.023 per cent and
0.031 per cent
respectively,
Sullivan), 8
of approximately two years.
and which
since
March 26,
half lives
Subsequent analyses of several soil
samples from Rongelap Atoll which had been
tervals
have
1954,
-l-
showed the
collected at
presence
of
inthese