Radiological 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 as follows:
1) External radiation levels significantly higher on some islands in an atoll compared to levels on lightly
contaminated islands.
2) Fission and activation product radioactivity in certain 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) Plutonium and americium
isotopes in the surface soil.
These factors are illustrated by data in Tables 1 through 4 taken from
previous radiological survey reports.
Table 1.
=
Bikini
Island
Gamma Radiation Rates in Bikini Atoll”
-
Weathered areas
Close to shore
Island center
-Hot spots
Eneu
Nam
(oR/hr)
Exposure rate
Range
.010-,120
-910-.030
-020-,040
.950-.080
-080-,120+
-002-=,010
Maior contributors
—ASICs
137
CS, 35
-010-,330
60¢0,*?"Cs
.003-.010
x
Aerokoj-Emenman complex:
Aerokoj, Aerokojlol
Bikdrin, Lele
.001-.010
.006-,010
*
‘x
East Eneman
West Eneman
.001-.010
-020-,570
Outer edge
Island center
N.E, corner
Bokantuak, Iomelan,
-010-.030
»015-.150
»110-,330
Rojkere, Eonjebi
Eneman
Enidrik
East Enidrik
West Enidrik
.001+.570
.003=,235
-003-.030
-910-,235
Luko j
.060-. 200
Bokbata
.010=,030
Jelete
Oroken
Bokaetoktok
Bokdrolul
Aomen-Troij complex:
Aonen
Lomilik
Odrik, Llroij
-060-,130
015+.045
-910-.035
.020-.050
-005-.020
,020-, 330
«010=,040
80¢9, 125g, 102m,
6069, 129ep, 102m,
8009, $55, Oma,
bad
we
re
$065, 13%cs
B55, 12555
tek
*see ref. 9,
tk
No soil sample or field spectra measurements.
In some cases, the predicted doses and dose coumitments derived from survey information for Bikini
and Enewetak Atolls approach or even exceed national and international radiacion protection standards for
.certain living and dietary patterns, Corrective actions or restrictions mist be placed on use of these
ratokis 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.
Enviro mental 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 rad{ation dose rates higher than
natural background. Aside from periodic re-evaluations to escablish 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 repre-
sentative samples of local diets for laboratory analysis and dose commitment updates. New locally
grown food items are becoming available in small quantities 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 is sufficient to support the anticipated populations which will one day live there (though such crops are currently being developed or planned).
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