- 63 chemically similar elements.

The abundance in sea water

of strontium and calcium, which is chemically similar to
strontium, is part of the reason that Sr90 is not abundant

in marine organisms (Table IV).

Another factor is the

low specific activity for sr9° in sea water due to
mixing and dilutien by ocean waters.

The low level of

csl47 in marine organisms cannot be accounted for entirely
for the same reasons, because the stable isotopes of
cesium are scarce in the sea.

However,

potassium,

an

element chemically similar to cesium, is abundant (Table

IV) and also, the specific activity for Csl57 in sea water
is low.
The Sr?° in canned tuna fish and salmon has been
determined by the Health and Safety Laboratory of the U.S.
Atomic Energy Commission.

In 48 analyses of samples re-

ceived between April 20, 1956 and August 8, 1957, the
highest value was ,.004 wuc/g, wet weight (U. S. Atomic
Energy Commission report HASL 42 1958).

Because the

values were very low and there seemed to be no trend in
time or location,

arily.

the sampling was discontinued tempor-

The health hazard from Sr9° which is determined

from the ratio of Sr9° to calcium is low for fish because

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