Radiolopical Concerns
The primary radiological problems are the result of residual fission and activation products in the
terrestrial environment.
They have been
identified by previous environmental
surveys
ternal radiation levels significantly higher on some islands in an atoll compared
contaminated islands.
2) Fission and activation oroeduct radioactivity in certain
as
follows:
1)
Ex-
to levels on light!y
terrestrial food items
now growing on islands of these atolls and the possibility that unacceptable levels of these radionuclides
may appear in foods, plants and animals newly introduced into these atolls.
3) Radioactivity in the
ground water, a possible source of drinking water and water for irrigation,
4) Plutoni.n and americitm
isotopes in the surface soil.
These factors are illustrated by data in Tables 1 thro.
» taken from
previous radiological survey reports.
Table 1.
Gamma Radiation Rates in Bikini Atoll”
(mR / hr)
Bikini
Exposure rate
Range
Island
.010-.120
Weathered areas
Close to-shore
Island center
Hot spots
Eneu
Nan
Outer edge
Island center
N.E. corner
Bokantuak, Iomelan,
Rojkere, Eonjebi
Aerokoj-Emenman complex:
Aerokoj, Aerokojlol
Bikdrin, Lele
Eneman
East Eneman
West Eneman
-010-.030
-020-,040
.050-.080
-080-. 120+
.002-.010
~010-.330
-010-.030
-015-+.150
.110-.330
.003-.010
Lukoj
“060-.200
Bokbata
Aomen-lroij complex:
Aomen
Lomi lik
C83,
60¢o,
Cs
ak
ek
wk
60¢9 125,, 102m,
6065, 1255, 102m,
-
606, 125g, 102m,
060.130
-015=.045
.010-.035
-020-.050
*
**
bated
/010-,030
6069, 1375
.005~.020
Ps
.010-.040
Saad
.020-.330
Odrik, Iroij
+
137
.003-.030
.010-,.235
Jelete
Oroken
Bokaetoktok
Bokdrolul
-
— Ls'cs
.003-,235
East Enidrik
West Enidrik
*
Maior contributors
.001-,010
.006-.010
-001-,570
-001-.010
«020-.570
Enidrik
tk
.
8065, 12555
See ref, 9.
No soil sample or field spectra measurements.
In some cases, the predicted doses and dose commitments derived from survey information for Bikini
and Enewetak Atolls approach or even exceed national and international radiation protection standards for
certain living and dietary patterns.
Corrective actions or restrictions must be placed on use of these
atolls and their resources to assure that the applicable radiation standards are not exceeded.
Herein
lies the primary justification for the continuing environmental followup surveys sponsored by ERDA.
Environmental Monitoring
The most important sources of exposure to people living on Rongelap and to future residents of Bikini
and Enewetak Atolls are from internal deposition of radioisotopes from certain elements in the human
diet, and from the long term occupancy of islands having external radiation dose rates higher than
natural background,
Aside from periodic re-evaluations to establish trends in external dose rate
reduction,
external radiation monitoring will
assume
less
significance,
compared
to monitoring of the
food chain, as time passes.
At present, annual visits are being made to identify and collect representative samples of local diets for laboratory analysis and dose commitment updates.
New locally
grown food items are becoming available in small quanticies on Bikini Island as a result of the experi-
mental agricultural
practices of a small group of caretaker families
living there.
Neither Bikini Atoll,
where radiological cleanup has been completed, nor Enewetak Atoll where clean up has not yet begun,
have a subsistence agriculture resource in being which 1s sufficient to support the anticipated pcpulations which will one day live there (though such crops are currently being developed or planned).