f
resulting in a density of 1.0.
Small samples, spiny lobster
hepatopancreas for example, were ashed, dissolved in hydrochloric acid,
and sealed in PVC pipe.
Oven-dried soil samples were compressed to a density of
1.35 in PVC pipe.
Spectrum resolution was done by Schonfeld's
of least squares.
(1965) method
A set of previously prepared reference spectra
for the different geometries and radionuclides was used.
All
values were corrected for decay to the date of collection.
The
error given for individual values is the 95% error.
Strontium-90 Analyses
Strontium-90 was determined by measuring the equilibrium
concentration of its 90y daughter.
Yttrium-90 was separated by
solvent extraction and precipitation techniques
(Petrow,
1965),
with stable yttrium serving as both a carrier and a yield determinant.
Recoveries ranged from 80 to 100%.
Iron-55 Analyses
Iron-55 was separated and purified by a combination of
solvent extraction and electrodeposition techniques
Beasley,
1967).
Recoveries generally exceeded 90%.
(Palmer and
Counting
was done by X-ray spectroscopy with a proportional counter in
conjunction with a multichannel analyzer.