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component of an insoluble particle or by adsorption of the
dissolved isotope to organic and inorganic scavengers present
in sea water.
(2) The cumulative effect of the deposition of particulate matter in settling basins on the bottom of a lagoon brings
about a greater concentration of radioactive settling particles
in the benthic than in the pelagic divisions and in their associated fauna.
(3)
Radioactive zine associated with a particulate phase
in sea water will be concentrated by carnivorous fish.
Ina
lagoon-type environment in which there is little exchange of
sedimentary material with the open sea,
there will be a greater
concentration of particulate radiozinc in the benthic carnivor-
ous fish than in fish of the pelagic division.
(4) The binding of zinc-65 by the biota prevented mixing
and flushing of the isotope from the lagoon.
5 years after its introduction as fallout,
For a period of
the pattern of dis-
tribution of zinc-65 in the lagoon reflected the conditions
imposed by the original fallout distribution.