:
oy
~
acer “
excretion levels of cesium'37 and strontium?? were measured from March 1954
through March 1958.
zinc®> levels were first measured in 1958 samples.
MATERIALS AND METHODS.
One hundred and forty one individual urine samples collected from ok March
1954 through 7 September 1954 were obtained by the Health and Safety Laboratory,
AEC.
Urine volumes were small (about 350 m1) and it was necessary to pool
samples.
This was done according to the age of the subjects and 19 samples of
pooled urine were assayed.
A 57 liter pooled urine sample from Rongelap was
collected and assayed in 1956 (3).
samples were assayed in 1957.
Three pooled samples and seven individual
Thirty individual urine samples were assayed in
1958.
In samples collected in 1954 and 1957 cesium-37 was scavanged by nickel
ferrocyanide (urine made strongly alkaline) and counted in a crystal well counter.
A twenty channel gamma-ray spectrum was determined for each sample and the cesium!
photo spectrum count rate used.
The 1958 samples were assayed directly for Cst37
zn°>, and KHO in 2.5 liter plastic containers placed on an 8 x 4 inch (TH activated)
sodium iodide crystal.
The activity for each radio-isotope was determined by
gamma-ray spectral analysis.
Sample activities were compared with known radio-
active standards (+ 5 percent) counted in the same geometry.
Strontiun?° was precipitated from urine as the carbonate.
Yttrium? was
separated and identified by its half-life using thin walled gas flow counters.
Urine samples were corrected for radio-active decay to the timeof collection.
There is some uncertainty as to the completeness and the duration of time
over which samples were collected and therefore twenty-four hour urine volumes
are not accurately known.
Potassium0 excretion, using 360 d/m or 2 gm K/day
indicates an average daily volume of about 1180 ml (+ 56 percent).
It was con-
venient to use one liter as an average 24 hour urine volume and to express radio-~
NM
assays in micromicrocuries per liter.