The present paper presents data obtained from analyses
of Pacific Ocean tune collected in 1967,
- 60
occurrence o£
Co
and
137
Cc s
as well as
1968 and 1969.
55
s
.
The
a8
Fe in tuna is discussed.
MATERIALS AND METHODS
Tissues of both light and dark muscle from tuna caught
between July 1967 and June’ 1969 were obtained at the Tokyo port
The samples were oven-dried
at the National Institute of Health,
Department of Food Control,
|
of landing of the Japane e fishery.
Tokyo,
under the supervision of Dr.
Seattle for analysis.
T. Kawabata and shipped to
Dates and locations of catches were
obtained from the vessels'
logs.
The species sampled were yellow-
fin (Taunnus albacares), bluefin (Thunnus thynnus), and big eye
(Thunnus chesuc).
The samples were redried in Seattle
and prepared for analy-
sis by gamwaa-ray spectrometry by compressing the tissues into
standard counting geometries.
After analysis for gamma-emitting
radionuclides, portions of the samples, usually 20 grams per
sample, were taken for analyses of iron-55 and stable iron,
Guplicate.
in
The light muscle and dark muscle obtained from the
fish were both analyzed for iron-55, but since
the
of the two tissues were similar,
iron-55
greater in the Gark muscle,
te
~
soe los
~ 7
ee
lentiy
chcained
w as
pans
and stable
9)
nad
Chi
a)
?
uu
a
;
°
©
oO
ry’
the specific activities
iron
as would
concentrations were
only the dark muscle from fish
analyzec,
art