-5-
were
the
hermit
and the
dopore ,
long the
» lang
he
weight basis than soft tissues.
Weighed samples of tissues in pliofilm bags were dried
overnight at 100° C and sent to the Applied Fisheries Laboratory in Seattle for processing,which was usually accomplished
about @ month after collecting.
2tained
In processing,
the samples in pliofilm bags were applied
to the plates(1 1/2-inch stainless steel, previously weighed),
ashed overnight at 5009 - 550° C, slurried with alcohol, and
en
dried.
ted
The plated ash received a few drops of Formvar
dissolved in ethylene dichloride (up to 1 mg dry equivalent)
and for
to affix the ash to the plate.
lable
The plates were then weighed,
and counted in methane gas-flow counters.
Except in the case of rats, counts were corrected back to
"ive-
date of collection using the decay rate of island soil
iteain-
(plate 7542) collected May 15, 1954 at Belle (Fig. 5, p. 11).
lliter
For rats the decay correction was based upon the individual
decay rate for each plate.
Self-absorption correction factors were based upon land
soil collected June 7, 1954 at Edna, the decay curve of which
(plate 9170) appears in Figure 5, page 11.
Within seven months
after Nectar an increase in average energy necessitated a reduction in the self-absorption correction factor for the later
The following tabulation illustrates these changes.
counting.
Ash weight
in mg/plate
Self-absorption correction factor for count ne
Before November 1, 1954 After November 1, 195
3
10
1.0
1.1
1.0
1.1
30
1.4
1.3
100
300
2.0
2.9
1000
1.6
1.9
4,3
2.5
Geometry and backscatter for the counters and plates used
required a combined correction factor of 1.54.
Coincidence
correction factors were determined and applied for the counters
employed.
For the decay curves plate counts were used,
corrected only for coincidence.
Applying these
-
-
correction factors gave values in disinte-
grations per minute per gram (d/m/g) of wet tissue as of the
KEYt0. serrinny,
ONE
ams
date of collection.
Processing techniques are further discussed
in UWFL-43 and WT-616. Three significant figures were retained
throughout the calculations, finally being rounded to two.
After plotting d/m/g against time the ordinate was in some
graphs calibrated also in picrocuries per kilogram (uc/kg), assuming 1 uc to equal 2.2 x 10° d/m.