’
in Chapter III of reference (1).
HrMATOLOGIC OBSERVATIONS
It 4s generally considered that changes in the blood are the most sensitive
biologic indices of exposure of living human beings to radiation.
Accordingly ex
tensive simple hematologic studies were performed on the Marshallese.
Since there
were no previous hematologic studies on the exposed Marshallese, it was necessary to
set up control groups of non exposed Marshalled of the same age and sex distribution
for comparative purposes.
I shall restrict my comments to the findings in the group
from Rongelap since the temporal sequence of events are identical in all of the exposed groups.
Of course the depression was less marked in the less severly exposed
groups.
Neutrophile Count
The ebsolute neutrophile count of both the younger and older age groups fell
during the second week to a value approximating 70 to 80% of that of the controls.
Following the depression there was an oscillation roughly around the control value
until about the 30th post exocsure day at which time there was a progressive decrease
in the blood count with minimum values being attained around the 45th day after ex-
posure.
It is of interest, that thedepression in the children, less than 5 years
of age was greater then in the individuals who were greater than 5 years of age.
Following this maximal depression there was a slow return of the neutrophile counts
towards normal.
However at 6 months they were still depressed.
years the neutrophile counts were back to the control level.
At cone yeer and two
However at 3 years
there was a drop in the absolute mean neutrcphile count but this also occurred in
the control population,
It is not known whether lowered counts represent a popu-
lation trend as has been noted in the Japanese for both irradiated and non irradiated
populations, or whether itis merely a statistical fluctuation that is to be expected ©
in. this type of study.
Lymphocyte Count
More work is necessary on this point.
(IDOE ARCHIVES