-3-
from the fresh or frozen specimens, at the Eniwetok Marine
Biological Laboratory.
ts,
The tissues were weighed at the time of
dissection and then dried.
The packaged dried samples, together
with data cards, were sent by air mail to the Applied Fishertes
Leboratory, University of Washington, for further processing.
There the dried samples were ashed at temperatures up to
550°C on stainless steel counting plates and then counted in an
internal gas-flow counting chamber.
The counts per plate were
converted to disintegrations per minute per gram (d/m/g) of wet
tissue,
as of the date of collection, by correcting for sample
weight, geometry, backscatter, self-absorption, coincidence and
decay.
(See WT-616 (UWPL-33) for a more complete discussion of
these procedures. )
The decay corrections for all tissues except carapace were
based on the decay rate of a soil sample collected at Belle
Island the day after the Nectar shot.
Decay corrections for the
carapace were based on the decay rate of 97904 y90 and sr89 which
constituted virtually 100 per cent of its activity at the time
the chemical determinations were made.
The decay correction
factors ranged from 1.09 to 12.7.
The variation in amount of radioactivity for each tissue at
each collection date, although great, {Appendix Table 1) was not
great enough to obscure general trends in changes of radioactivity with time or differences in levels of radioactivity
between tissues.
The term "activity" as used here means radioactivity per
unit weight.