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Project Number
acific Northwest Laboratories
April 18, 1978
To
Bill Bair
From Dick Gilbert Det
Subject Suggested reconmendations to DOE on the Basis of
the April 13-14, 1978 Meeting of the Advisory
Group on Cleanup of Enewetak Atoll in Las Vegas.
Based on my observations during the subject meeting and my phone conversation with Madaline Barnes (statistician for cleanup effort) on April 17,
the following items seem to be important to point out to DOE.
Averaging
I see no compelling reason to alter the previously agreed upon plan to
consider each 1/4 or 1/2 hectare area separately for cleanup.
I see no
advantage to using an "average island" soil concentration for making cleanup
decisions.
‘Apparently, the concept of an average island concentration arose
during the April 13-14 meeting since Bill Robison, et al had used the term
in obtaining dose estimates for the Enewetak Atoll.
The term was perhaps
inappropriate because these authors did not use actual soil concentration
data for their computations.
Instead dose estimates were obtained for a series
of hypothetical "average island" soil concentrations.
There are a number of
methods that could be used for using actual soil data to make dose assessments.
Compute the dose on the basis of highest estimated soil concentration
AYOLISOd 34
for any unit (of 1/4 or 1/2 hectare size) on the island.
This method
could result in a very conservative dose estimate if most units on
the island had much lower concentrations than the highest unit.
Average al] the unit (1/4 or 1/2 hectare) average soil concentrations
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on an island and use this grand average to estimate potential dose.
This method weights all units equally, even though some units would
undoubtedly have greater utilization by inhabitants than other units.
' 3.
A conservative approach would be to use the cleanup criteria desig-
nation for the island (40, 100, or 400 pCi/g, for village, agricultural,
or picnic islands, respectively).
Dose estimates for this option were
obtained by Robison, et al. in their dose assessment paper presented to
us at the meetings.
Conservative dose estimates are likely since most
units have average soil concentrations much below these cleanup criteria.
§4—-1900-00!1
(3-71)