Thtyreme ee 8 bine cm
INTERNAL DEPOSETION OF RADIONUCLIDES
5.3
Imecruri Coetamination im
Huemen Beings
Tue Ixreawat Conramination study was be-
- ee ee ee
gun 15 days post-detonation with the collection
of pooled 24 hour «rine samples from the
Marshalless and American groups. Mazimem
As a complete radiorhemical analysis of all
the urine samples was not feasible, samples were
analysed for only “r*, He'®. the rare earth
group and fissile material. These analyses are
the most useful for evaluating the concentra-
tion and identity of all the potentially hazardous internally deposited radicactive tsotopes.
which the contaminants remaining in the body
activity of all the samples.
To facilitate the processing of the large namber of urine samples sent from the field, a sraa-
days after internal contamination. By | week
an approximate equilibrium state is reached in
are firmly fixed, chiefly in the skeletal tissues,
The activity in the urine then derives from
radicetements which have been replaced in the
Thus,
the study made is ementially that of an equihibeium condition.
The urine samples were sent to laboratores
in the United States for analysis, since the high
background encountered in the field masked the
relatively low levels of activity in the aliquot
yamples used. A field laboratory is most desirable for a rapid survey, and was shown to be
feasible, if adequate facilities are provided for
the counting of the samples.
The first urine san:ples, mentioned above,
were collected for the Los Alamos Scientific
laboratory (I.ASL). Similar samples collected’ $4 duys post detonation were also sent
there. On the 23rd, 24th and 47th days post
detonation, 24-hour urine collections from each
dividual from Rongelap and Ailinginae were
sent tothe New York Operations Office, Atomic
Energy Commission (NYOO-AEC) for analysis, In addition, samples from representative individuals in these groups were collected
21, 3 and 6 months post detonation and sent
to NYOOLAEC.
The USNRDIL collected samples from each
member of the exposed groups at 45 and 46 days
jpaost detonation. Samples from representatives of these groups were also collected at 2t.,
Sand 6 months by the USNRDILL In addition,
samples fronia representative group of 6 Amertcans and 20) Marshallese were collected for 6
consecutive days beginning 33) days post
detonation.
+ -erepe
5.31 BMocheds
activity in the urine orcurs during the first few
natural process of biological turnover.
2a732 °°
oe
Measurement was also made of the gros beta
ning method for beta measurement consisting
of a basic oxalate precipitation with a lanthe-
num carrer was employed on an aliquot of the
24-hour urine samples. This method rapidly
concentrates the radicactive elements into a
siuall volume and eliminates the normal Ko
background.
A carbonate precipitation of the
entire 24-hour sample increased the sensitivity
of measurement sufficiently for analysis of
samples collected later than 21.. months post
detonation.
The beta activity wan counted with a thin end
window (reiger-Muller counter. The counter
was calibrated with a UO, standard, and an
appropriate correction for self-ahsorption was
made using a Sr® standard.
5.32
Findings and Incerpretations
1. Beta Activity of the Urine. Internal depasition of radioactive elements was evidenced
by the presence of significant amounts of beta
activity in the urine. This activity decreased
rapidly as a function of time, as it was derived
chiefly from short-lived radioisotopes. For
example, at 3 months post detonation, the mean
activity of the urine of adults from Rongelap
was 28 percent of the value measured 45 days
post detonation, and at 6 montha, the activity
in the urine was barely detectable in most of the
individuals.
Comparison of the means of the urine samples for the adults from Kongelap and
Ailinginae and from Americans from Rongerk
indicated that af 4 days pest detonation the