obtained from independent random samples of
such items collected nj days per year from among
the possible selections of the type available on
Rongelap. The corresponding cumulative dose
D(t) from all major exposure routes was
estimated as:
__
Mi 365
assumed expected value of 0.9, andj variability of
(F) was assumed to be uniformip distributed
between 0.8 and 1. These fssumptions
approximately characterize the efnpirical data
on the value of F obtained for 17 individuals
reported by Schwartz and Dunning
Interindividual variability in
(4)
}
where c is a unit-conversion constant, where
D,(t) and Din(t) are approximations of adult
external-gamma
dose (modeled
as
interindividually
variable)
and
Am+Pu
inhalation dose (modeled deterministically),
respectively, and where Eq. (4) was evaluated
using Monte-Carlo methods (see Appendix D).
and on data reviewed by Schwartz And Dunning
(1982) indicating slightly greater variability
associated with the parameteq
among 53
Variability in D,(t) was modeled using data
from Table 3 and assumptions stated above (Dose
Methodology, External Exposure, Gamma
Radiation) concerning average times spent in the
house, house surroundings,village area, island
interior and beach/lagoon areas, and
corresponding mean exposure rates. From these
assumptions, it was estimated that household
and house-area exposures would typically
account for ~64% of total external gamma dose,
with a coefficient of variation (CV), i.e., the
standard deviation divided by the arithmetic
H and SDg was obtained using
moments.
Uncertainty pertainirfg
to be uniformly distributed (bet
pertaining
1.107), such that the true value of
to any specific individual was aken to lie
within 10% of the expected vz uve for that
individual.
The population-average value
annual intake, (R)}, of total 137Cs a
mean, with respect to interindividual
variability equal to'~45%. The remainder of
external gamma dose was assumed to be equal to
the corresponding population-average value,
reflecting an expected interindividual averaging
over commonly frequented island areas.
‘Accordingly, external gamma dose was modeled
as
D,(t}=(0.36+Y)D,(t},
where
Y
is a
lognormally distributed variability factor with
expectation 0.64 and geometric standard ©
deviation (SDg) = 1.536.
Variability in the fraction, F, of ingested
137Cs input to the dominant biological
compartment was assumed to be uniformly
distributed between an uncertain lower bound
ranging between 0.71 and 0.89, and an upper
bound of 1. Thus, uncertainty in F was assumed
to be uniformly distributed within + 5% of an
expected daily intakes, (R;;) was nlodeled using
the empirical distribution of aferage daily
uptakes in Bq kg-! calculated fram
the foodsurvey data for these same 34 aflult Ujelang
females, which was here mukiplicatively
scaled to have the expected daily population
average value of (31.3 Bq d-170 kg-}), where 31
Bq d-! was taken (see Table 20) to Be 99% of the
mean daily dose.
This scale empirical
distribution does not significantly Hiffer from a
lognormal distribution having [n expected
value, GM, and SDgof 0.447 Bq kg“d-", 0.319 Bq
kg-! d-!, and SD, = 0.8217, respectively (see
Figure 16); p>0.15 using Stepheg’s modified
Kolmolgorov-Smirnov, Cramer-v@n-Mises, or