-10-
particulate matter suspended in the water.
The filtrate was then
carried through a standard sulfide precipitate procedure for the
separation of strontium-90 and cesium-137 from other radionuclides
present in the sample.
Strontium-90 was separated from cesium-137
by the standard oxalate procedure.
Five samples of surface water
were analyzed for strontium-90 and cesium-137 and the remainder
of the samples were analyzed only for those radionuclides precipitated by the sulfide procedure.
The results of these analyses
are expressed in picocuries per liter of water at time af collectim.
The arrangement for the gamma spectrum analyses of the fish,
plankton and water samples included a three-inch by three-inch
sodium iodide detector and a multichannel analyzer
512).
(Nuclear Data
The time of counting varied from 40 to 800 minutes de-
pending upon the size of the sample and upon the expected level
of radioactivity in the sample.
Part of the samples were pro-
cessed at Christmas Island but the bulk of the collections were
frozen or dried and shipped to Seattle for analyses.
The analyzer output data were processed by an IBM computer
(Model 709).
The computer program was designed to analyze the
counting data for five comparatively long-lived radionuclides,
potassium-40,
cobalt-60,
cerium-141,144,
zine-65,
cesium-137,
and
as well as for four comparatively short-lived
radionuclides, barium-lanthanum-140,
ruthenium-103,
cobalt-57,
and iod.-e-i31.
zirconium-niobium-95,
Except for potassium-40,
a