FISSION-PRODUCT DEPOSITION AND DIETARY LEVELS
IN THE CHICAGO AREA
P, F. GUSTAFSON, 58. S. BRAR, and S. E. MUNIAK
Argonne National Laboratory, Argonne, Illinois
ABSTRACT
Measurements of gamma-emitting fission products in soil core samples
have been made by gamma-ray spectrometry since 1957, These provide
a running inventory of ground deposition and accumulation of a number
of radionuclides, Concurrent measurements of fission products in air
and in precipitation have madeit possible to relate airborne activity to
deposition. The only gamma-emitting fission product present in soil
which is of biological importance is '*’Cs. The other gamma emitters
constitute a source of external radiation of varying magnitude but are
not metabolically active. Quarterly food sampling in the Chicago area
has been conducted in conjunction with the Health and Safety Laboratory
Tri-City Sampling Program since April 1961. These samples have been
analyzed for "Cs and have shown traces of other gamma-emitting
fission or activation products from time to time, notably °*“Mn. Changes
in the '*’Cs level in the diet with time have been compared with whole-
body measurements of 87Cs8 in Chicago residents. The concentration of
‘8ICg in human rib bone was determined in 1961 prior to the resumption
of nuclear testing and in specimens collected in 1962-—1963.
ANALYSES
Soil core samples have been collected from the Argonne, II1., site
and analyzed for gamma-emitting radioactivity since 1957. Two cores
4 in, in diameter and 6 in. deep were taken from two locations on the
site at each sample collection, The cores were air-dried in the labora-
tory, pulverized, and homogenized, and approximately 2 kg was placed
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