The Rengelap unexposed group ie expected te remain near the upper range
ef the prospective annual risk limit recommended by ICRP.
Moving away from
Rongelap at this time will not eignifieancly aleer future annual Pigke
Tn
large part, the unexposed group's future gisk will be from radiation exposure
received during the last 27 years.
Reeent Bioassay Results from Pu
The estimates of radiation dese and asseeiated risks given previously doe
not imelude the contriburcion from craneuranic nuclides.
We anticipate this
dose to be negligible based upon estimates by BLiil Rebigon which apply to
former Bikinians, however, thie has sot been verdfted through bicassay. We
have analyzed about 500 test samples using alpha iieuid seintililacion (PERALS)
procedures.
Test samples were run af two outside laboratories in addition te
eur work ec BNL.
fn July 1984 we identified 46 Harshell Islands urine samples
which we suspected as either not containing Po ef es containing lew levels of
Fue
Briefly, we wet ashed these eamples and golvent extracted to obtain pure
Pue
We chen introduced the Pu inte an extractive seintdilater se that the
gample could be counted on PERALS.
The minimum detection limit for this
method is 190 uBq (5 fCi).
& number of these Marshall Islands urine samples shewed alpha counts in
the 2359p region, however, on further investigation we moced that some of this
activity was due to the decay of maturally eceurring 21056,
Experiments done
here end at one other laboratory indicated to we that the solvent extraction
8
procedure unexpectedly allows significant emounts of 2105, te pass into the