before
counting.
oven at 96° C,
ona
planchet
The
samples of bottom sand were dried in an
and 100-mg portions of the dried material were spread
and dry ashed before counting.
The counts of radio-
activity were corrected to the date of collection;
correct for radioactive decay (decay factor) for all
the factors used to
but three of the
samples were based on a soil sample collected on May 15, 1954,at Belle
Island.
For the early collections decay factors as high as
16.2 were
used, whereas for the last collection a decay factor of only 1.02 was
applied.
Corrections also were made for self-absorption, backscatter
(0.77), geometry (2.00), and coincidence for those samples used in
determining absolute amounts of radioactivity.
factor for coincidence was
Only the correction
applied to samples used for determining
radioactive decay.
The amounts of radioactivity are expressed in microcuries
kilogram (ye/kg)
of
per
wet tissue for the algae samples, in uc/kg of dry
matter for the sand samples,
and in disintegrations per minute per mil-
liliter (d/m/m1) for the water samples.
The rates of radioactive decay of individual samples of algae,
sand,
and water were determined by counting the samples on at least three jifferent
dates.
The decay of
mixed fission products approximates
0
a linear log-log relationship for the period involved in this study"! Y