The accumulation of data from these surveysis
becomingincreasingly voluminous. Since conditions have not been favorable for performance of
extensive Statistical analyses or use of electronic
computing procedures to store and manipulate the
data, the annual survey reports published by this
Laboratory are made as complete as possible. This
report, therefore, includes a considerable amount
of raw data, much of it in appendices, so that
others may have an opportunity to make further
calculations if desired.
Summary of Past Findings
Reports have been published on the findings of
surveys madeat the following times after exposure: initial examination,’ 6 months,” | year,? 2
years,’ 3 years,° 4 years,° and 5 and 6 years.’ The
following is a brief summary of the findings previously reported.
During the first 24 to 48 hr after exposure,
about % of the Rongelap people experienced
anorexia and nausea. A few vomited and had
diarrhea. Many also experienced itching and
burning of the skin, and a few complained oflach-
rymation and burningofthe eves. Following this,
the people remained asymptomatic until about 2
weeksafter the accident, when cutaneouslesions
and loss of hair developed, due largelvto betair-
radiation of the skin. It was apparent when the
people were first examined, a fewdaysafter expo-
sure, that the lymphocytes were considerablvdepressed andthat significant doses of radiation had
probablybeen received. In addition to the wholebodydose of radiation and the beta irradiation of
the skin, radiochemical analyses of the urine
showed that measurable amountsof radioactive
material had also been absorbedinternally. The
effects of the radiation can best be summarized
under three headings according to the modeofexposure: penetratingirradiation, skin irradiation,
andinternalirradiation.
PENETRATING IRRADIATION
The changesin the peripheral blood of the more
heavily exposed Rongelap people whoreceived
175 r will be reviewed in the section on hematological examinations(see Figures 34, 39, and 43,
and Appendices | and 2). The changes in the
Ailingnae and Utirik groups were similar but less
marked. Certain unexplained fluctuations have
occurred from year to year in the peripheral blood
levels of the comparison populations as well as of
the exposed groups. The mean /eukocyte level of the
exposed group showed a marked decreaseat the
time of the 1960 survey (no unexposed people
were examined). Depression of the peripheral
blood elements as represented by mean population levels occurred as follows.
Lymphocytesfell promptly and by the third day
were about 55% of the control values in adults,
and slightly lower in children. There was only
slight recovery after six months. At 2 years, al-
though further recovery was evident, the mean
values of these cells were still found to be below
the comparison population levels (75 to 80%). At
3 years the mean lymphocyte counts wereslightly
below those of the comparison population. At 4
years the mean level appeared to be about the
sameas that of the comparison population, but
many counts remained lower. However,at 5 years,
lymphocyte levels appeared for the first time to equal
those of the unexposed group, except that analyses
showed more counts below the average of the unexposed group.
Neutrophil levels fluctuated considerably during the first few weeks but fell gradually to a low
of about 30% of comparison population levels bv
the 6th week viter exposure. Slowrecoveryensued, but at 6 months thev werestill slightly below
the unexposed levels. However, by | vear post exposure they had returned to the level of the comparison population and have remained so, with
the possible exception of those of children < 12
years old, which generally have been lower than
those of the unexposed children of comparable
age.
Platelets fell to about 30% of the unexposed
values by the 4th week. By 6 months they had
reached 75% of the controls; at 1 year the mean
platelet count wasstill below that of the control
population but higher than at the 6-monthsurvey.
Although further increases were apparent at the
2-, 3-, and 4-year examinations, the levels were
still below those of the comparison population. At
3 years post exposure, exposed peoplestill had
mean platelet levels 10 to 15% below those of the
unexposed group.
Changes in hematocrit were not remarkable in
any of the groups during the period of maximum
depression of leukocytes. However, it appeared