C
Table 2.
Population breakdown by age and geographical living patterns.
Infants and
small children
Children and
adolescents
Men
Women
Age bracket (years)
0-4
§-19
20+
20+
Fraction of population (%)
16
41
22
21
Inside home
50
30
30
30
Within 10 m of home
1s
10
5
10
Elsewhere in village
§
10
5
10
Beach
5
5
5
5
Interior of island
5
15
20
1S
Lagoon
0
10
10
5
- 20
20
25
25
Fraction of time spent in
respective areas (%):
Other islands
shown as area 3 in Fig. 4.
and 6 are identical.
As far as the external dose assessment is concerned, cases 5
Since the expected living patterns are most likely to differ
between the various age groups, it is necessary to utilize the age distribution data
presented in Table 2.
These data were obtained from the 1974 census taken on Kili Island
of the 784 persons who claim land rights on Bikini Atoll. 4
The geographical living patterns,
also shown in Table 2, were assumed to be similar to those expected for the returning
Enewetak people.?
Even though the gamma-ray exposure rates vary widely, it was necessary, for the
purpose of the external dose calculations, to derive the most reasonable values of the
Mean exposure rates for each specific geographical area under consideration.
shown in Table 3.
These are
The mean exposure rates for specific areas on Bikini Island were
obtained by weighting the mean exposure rates within each contour interval with the area
within the contour.
Since the exposure rates on Eneu Island are relatively uniform, the
Mean exposure rates were chosen by inspection of Fig. 3.
Since this survey did not include
the other islands of the atoll, it was necessary to rely on data from previous surveys to
estimate the contribution the radioactivities on these islands make to the total population
dose.
Gamma exposure rate data reported by Bennett and Beck,” Held,° Lynch et al.,°
Gustafson,’ Smith and Moore,® and Robison et al.? were used for this purpose.
Their results
in conjunction with a simplified area weighting scheme yielded the values presented in
Table 3.
It should be pointed out that these are rough estimates since the data are
scarce and were collected over a span of almost ten years.
The exposure rate over the
lagoon was estimated to be 3.3 uR/hr due to the cosmic ray contribution and an additional
a