In these evaluations, it should be emphasized that dosages through various
pathways are estinated on the Dvasis of environmental data and considerations
of expected living patterns and dietary habits.
‘hile "radiation standards"
do not exist for environmental conta:ination levels in substances sucii as
soil and foodstuffs, there is general agreement in terms of conservative
stofels of these pathiavs and
cle relavionships betveen a certain level in
the environment and the likely dose to result from the pathway exposure.
The area of plutonium in soils, however, is one for which there is no
general agreement as to the quantitative relationship between levels in
soils and dosages to be expected through the inhalation pathway,
the
primary one through which man can receive a sisnificant dose fron
plutonium.
The ICRP recomenis a maxinun vermissible average concentration
(PC) of 1 picocurie per cubic meter (pCi/m3) of air for "insoluble"
plutonium and 0.06 pCi/n? for "soluble" plutonium for unrestricted areas.
“hile the plutonium in the soil at Enewetak is thought to be typical of
world-ide fallout, and therefore insoluble, 9.96 nCi/m? will be used
for the sake of conservatism.
Appendix A of Inewetak Radiolovical Survev, 1VO-140, presents two possible
metnods for deriving the exposures that may occur turough the inhalation
pathway for plutonium in soil.
(This is the pathway of interest for the
reteitly
present although it is zeereanteed that for the very distant future,
ingestion may become nore important by comparison,
Table 250 of Appendix
TI shows that exposure to bone, liver, and lung from 239?u are expected
to pe a fev hundredths of a ram in 3) vears for vatihways other than
innalation.)
This material is sroducel as Attachinent T of this section
111-10