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clams and scallops like zooplankton readily accumulate
radionuclides in the form of particles but many of the
radionuclides that occur in the digestive tract are not
absorbed.
In laboratory experiments,
strontium radioiso-
topes are taken up and deposited in the shells of oysters,
clams and scallops but not in the soft tissues (Chipman
1959).
In both the field and the laboratory, it was
found that marine fish absorb few of the fission products
from the digestive tract,
radioisotopes in muscle,
and do not concentrate strontium
but do absorb zn©5 very rapidly.
Although little csl37 nas peen found in the marine organ-
isms from the Bikini-Eniwetok area, Csl37 has been taken
up and concentrated in the muscle by fish and shellfish in
laboratory experiments,
and therefore is regarded as the
fission product with the greatest potential hazard.
The
conditions that make for a higher concentration of csl57
in the laboratory than in the field are not known.
In the
field the concentration of cesium in four types of plankton
is less than in sea water,
as determined by Ketchum and
Bowen (1958), which indicates that there is not a great
demand for cesium at least by some types of plankton.
Lastly, in both the field and laboratory observations it