6
204
THE SHORTER-TERM BIOLOGICAL HAZARDS OF
A FALLOUT FIELD
DISCUSSION
R. G. Lindberg and K. IT. ‘Larson
Dr. Stannarp
(University
One very simple question.
of
Rochester).
Were these figures
for particle size on a mass hasis average or
number basis?
Drs, Linpzers.
The technique has been to
take»soil sample from a known area, and using
standard soil methods break if down to the
particle size in the soil.
So the total activityis
an expression of the activity in a particular
size fraction and does not refleet the total
number of particles involved nor any characteristics of that purticle except size. The soil
acts as a carrier for the separation,
—~
RESIDUAL CONTAMINATION OF PLANTS, ANIMALS, SOIL,
AND WATER OF THE MARSHALL ISLANDS TWO YEARS
FOLLOWING OPERATION CASTLE FALLOUT
Presented by H. V. Weiss
U8. Naval Radiological Defense Laboratory, San Francisco, California
The object of this study was to determine the
persistence and fate of radioactive material in
the biological systems and in the physical
environment of these Marshall Islands contaminated by fallout from the 1 March 1954
The gross beta activity of the plant specimens
analyzed is recorded in
ing to the island
was recovered.
Table
1
from which the
accordsample
The data were corrected for
the counting efficiency of Sr® and presented as
nuclear detonation. For this purpose a resurveyof the islands was conducted in Febru-
corrected counts perminute per kilogram of wet
Radiological Defonse Laboratory. Specimens
of animals (land and marine) and birds, and
samples of plants, soil and water were collected
for analysis. Radio assays for gross beta and
gamma activity were conducted and in addition radiochemical determination of individual
fission products and induced activities were
made.
most samples was so low as to prevent such
evaluation with expediency. Furthermore since
the nuclide composition varied among plants
and even within different sections of the same
plant, a blanket correction was impossible.
Portulaca was many times more active than
other plant specimens recovered from the same
island. Leaves of plants were generally more
was made of the contaminated atolls, [1] and
soil, water, and biological specimens were
that surfaces of leaves were not decontaminated
prior to analysis may account at least in part
ary 1956 by a groupof scientists from the Naval
A few weeks after the 1954 incident a survey
collected from Rongelap and Utirik. These
samples were analyzed and the results were
given in the Operation CASTLE, Project 4.1
report {2]. Soil and water samples contained
microcurie amounts of activity; barely detectable quantities were found in plants.
sample.
Empirical corrections for self-absorp-
tion were not applied because the activity of
active than their fruit counterpart.
The fact
for this difference.
Three stages of coconuts-—green, ripe, and
sprouting nut—were analyzed. Both green and
ripe pandanus kevs wore examined. No dis-
tinct differences between the stage of growth
Approximately 1 year following the nuclear detonation, a surveyof the islands indicated that
the activity was present in metabolic systems
and was still in the environment at lower but
significant levels {3]. The present study, conducted 2 years post-detonation, provides further
and activity were discernible.
Where possible the meat, milk, shell, and
husk of coconuts were analyzed separately.
Within the limits of the analysis, the activity
appeared equally distributed among these
fractions.
tion can be made of the potential hazard from
the ingestion of contaminated materials.
Gejen > Eniwetak, Eniaetok > Rongelap >
Sifo, Utirik > Likiep. Theseresults agree well
data on the persistence and distribution of the
fallout activity. From these data an evalua-
448029 0-—-58——15
The order of plant activities relative to the
island from which they were recovered was:
205