in global fallout debris ,23 it has not been detected elsewhere as a component
of any waste discharged to aquatic environments from nuclear facilities.
Most striking was the range of concentrations found in tissues and organs
among different species of fish collected at the same time and place (see
Appendix).
For three
species of reef fish,
mullet,
surgeonfish,
and
parrotfish, 20781 in most parts of the fish was usually below detection limits
by gamma spectrometry.
However, the radionuclide was consistently detected in
the muscle and other organs of goatfish and the pelagic lagoon fish.
Over 70%
of the whole-body activity of 20781 in goatfish and pelagic fish is associated
with the muscle tissue, whereas less than 5% (when detected) is found in the
muscle of mullet and surgeonfish.
Between 1977 and 1984, the concentrations
in goatfish muscle ranged from a high of 1360 pCi/kg wet weight to a low of
17 pCi/kg wet weight, with the lowest levels found in fish collected from the
eastern reef of the lagoon.
There was no clear trend in the data to indicate
that the concentration of 297Bi in the muscle of goatfish was changing with
time at some constant rate.
At B-1 and B-5, for example, the levels in muscle
tissue were significantly less during the period of 1981-1983, compared to the
concentrations measured in 1978.
On the other hand, at B-6 and B-12, the
concentrations measured in the muscle tissue of goatfish collected in 1984
were no different than the concentrations detected in 1978.
TRANSURANIUM RADIONUCLIDES IN FISH
Several
reports
on the concentrations of the transuranium elements in
Bikini fish have been published by this laboratory.9»!0,24
Only. previously
unpublished results and a few highlights from published data wil] be discusse
in this report.
The data in Table 6 show that both 239+240py and 24lam are not
significantly accumulated in the muscle tissue of any species of fish.
Less
than 1% of the total body burden of both 239+240py and 24lam is associated
with the muscle tissue of all reef species.
Somewhat higher fractions, but
lower concentrations, were found associated with muscle
species.
tissue of pelagic
The distributions of 239+240py and 24!Am among the other tissues o
the reef and pelagic species are also different.
For example,
the bone and
skin of reef fish contain much less of the total body burden than that of
:
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18