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Procedures Used in Collecting and Processing Samples and Recording
Radioactivity
The procedures used in collecting samples of biological material in the
Marshall Islands have evolved over a period of years.
An effort was made
during each expedition to obtain as complete a sample as necessary for an
adequate evaluation of the problems studied, without completely swamping
the Laboratory with samples.
To carry out the program of sampling, specific animals and plants with
wide distribution have been selected for study.
From these selected samples
certain tissues are evaluated to determine the distribution of radioactivity.
Collections made in the field were retained on ice or frozen until they |
could be returned to the Division of Biology and Medicine field laboratory
at Parry Island.
There the organisms were identified, selected tissues
were dissected, weighed and then dried.
The packaged dried samples, to-
gether with the data cards, were sent by airmail to the Applied Fisheries
Laboratory, University of Washington for further processing.
At the Applied Fisheries Laboratory, the dried samples were ashed at
temperatures up to 540°C, cooled, slurried, dried, 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.
For a more complete discussion
of these procedures see WT-616 a
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