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To:
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Hal tollister
W. J. Bair
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Lone
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7
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The Advisory Group fs of the opinion that the recommended cleanup criteria
as discussed in item 2 below will result {fn average transurani¢ radiation
doses to subsequently exposed populations thatwill be commensurate with
proposed EPA guidelines. The EPA considers its guidance levels to be
equivalent to a lifetime risk of about 14 premature cancer deaths per 109,090
persons exposed and to perhaps an equal number of genetic effects, although
these estiriates are based on many uncertain assumptions and are generally
considered to be quite conservative. An estimate of 14 cancers per 100,06
people would correspond to a 3% chance of one cancer appearing in a population
of 200 people exposed to EPA guidance levels for their lifetime; or
expressed differently, to a probability of one cancer in every 2100 years
(assuming a@ constant population size).
2.
Considering the physical and ecological limitations to removal of transuranics
from the Enewetek Atoll, the Advisory Group recommends the following. From
the information currently available and used for dose assessment, wo believe
that cleanup of all one-quarter or one-half* hectare areas exceeding (with
702 confidence) 40 pCi/g of surface (0 to 3 cm.) soils of village islands
will provide a reasonable expectation that doses in the bone and lung will
be commensurate with the EPA guidance. In terms of radiation dosesparing benefit to future inhabitatants, cleanup of a standard area
on a village island is worth about 4 times as much as cleanup to a
given level on an agricultural #sland and 12 times as much as cleanup
of the same area to the same level ona picnic island.. However, in
the light of existing contamination levels.and available cleanup
resources, it would appear that cleanup of @1] one-quarter hectare
areas on village islands that exceed 40 pCi/g should recefve first
priority. Because the other islanus may have increased use over thet
currently assumed, a second priority should be the cleenup of
agriculture island helf-hectare areas exceeding (with 70% confidence)
80 pCi/g. A third priority should be the cleanup of picnic island
half-hectare areas exceeding (with 70% confidence) 169 pCi/g.
If
“resources are exhausted, some islands may not be cleaned up; final
from the other islands to Runit.
Department of Energy
\ Historian’s Office
ARCHIVES
*y/4 hectareif TEP readings
50 a noter grid is used.
are taken on a 25 meter grid; 1/2 hectare if a
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the village islands and, perhaps, from the agricultural islands
should be considered for lowering the average surface contamination
levels and reducing the logistics problems of transporting the soil
swe ne pmee he»
pemnanently quarantined. We note that the soil profile on Pearl is
anomalous since the concentration of transuranics appears to be
uniform with depth. We believe that the possibility of effective
cleanup for use as a village or agriculture island is remote. flowever,
the possibility of covering Pearl with the less contaminated soil from
+ trem meee eee
dose assessment may indicate that these islands will have to be