EARLY FOOD-CHAIN KINETICS
OF RADIONUCLIDES FOLLOWING CLOSE-IN FALLOUT
FROM A SINGLE NUCLEAR DETONATION
WILLIAM E. MARTIN *
University of California at Los Angeles, Los Angeles, California
ABSTRACT
Plant samples and rabbits were collected from representative locations
in the Sedan fallout field before and at various times after the detonation. Radiochemical and statistical analyses indicated highly significant
correlations between estimates of gamma dose rates and maximum
concentrations of ™Sr or ‘I in plant samples and in the stomach con-
tents, bone ash, or thyroids of rabbits collected between 15 and 110
miles from ground zero.
The effective half-lives of "Sr and ''I on fallout-contaminated
plants were approximately 18 and 5.0 to 5.5 days, respectively. Maximum concentrations of ®Sr in rabbit bone ash occurred about 30 days
after the detonation and remained high for at least 60 days; but maxi-
mum concentrations of '!I in rabbit thyroids occurred by or before
five days and then declined to pre-Sedan levels in less than 60 days
after the detonation.
:
Deterministic exponential models were formulated and found to
function satisfactorily, with parameter values derived from the data, in
providing a partial explanation of the quantitative kinetic relations be-
tween initial concentrations of ®Sr and '%4I on plants and subsequent
concentrations in the bone ash or thyroids of rabbits collected in the
Sedan fallout field. Major sources of error in the estimation of inputparameter values and in the use of such models to makepredictions
are described and discussed.
Similar models were proposed for the study of radionuclide kinet-
ics in human food chains (i.e., pasture plants, cow milk, and human
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