isotopes in appreciable amounts.
Detailed studies were undertaken to
establish with certainty the identity of the isotopes and to determine
their contribution to the total activity in the Rongelap soil.
MATERIALS AND METHODS
A 1.68-gram portion of soil ash, equivalent to 18.1 grams of dry
soil, taken from the top inch in a bird nesting area at Kabelie Island
on July 18, 1957, was dissolved in 0.2 N HCl and passed through an
ion-exchange column to separate the radioisotopes present in the
sample.
(The method used was described in detail by Lowman, Palumbo,
and South). 14
For this experiment a cationic resin (Dowex 50*) of 50-
100 mesh and column size of 0.942 cm2 x 61 cm was used.
The sample
and the eluting agents were passed through the column ata flow rate of
ene ml/min.
A summary of the volumes used and the radioisotopes
eluted is givenin Table 1.
Aliquots of the fractions collected
were
counted for beta and gamma activity, and those fractions with significant amounts of gamma radioactivity were analyzed in a single-channel,
50-position, automatic-advance, gamma spectrometer
well-type sodium iodide crystal.
* Available from Dow Chemical Co., Midland, Michigan
with a 2-inch,