Using the above ideas it might be possible then, to generate a
"reasonable" dietary intake for each of the 36 females.
-
This
scheme could be repeated day after day for as long a time period
as desired (easily done on the computer).
Note that we have
added variability by using different dietary intakes for individuals
and a range of possible daily intakes for each food item.
So far we have considered only variation in dietary intake.
Now
we must consider the concentration of Sr-90 in each days diet.
Consider a given food, say coconut.
While we do not have much data
on coconuts, it is reasonable to assume the distribution of concentrations in coconuts over the island would be lognormal if the
soil concentrations in which those coconuts grew is lognormal.
We
could imagine that coconuts are gathered from different trees and
hence that each days intake of coconut is a sample from a lognormal
distribution.
The parameters u and o (mean and standard deviation
of the logarithms of the data) of that distribution can be estimated
from the parameters of the soil distribution and the ratio data.
Using the estimated parameters ‘ and G, the computer could generate
a pCi/g concentration intake from ingesting coconut for each day.
The Sr-90 daily intake for each food could be so generated.
The
parameters of the lognormal distribution for each food would be
different if the food to soil ratios varied for each food (which they do).
For each of the 36 females the following data would hence be generated
(assume only 2 foods in the diet for ease of illustration), where
Food 1
Day
}
2
365
grams/day
pCi/g°
Food 2
—pCi/day
Gy
Gio
C1
Cio
G14C1y
Bil yp
Gi 365
1,365 91, 365°, 365
grams/day pCi/g_
pCi/day
G54
Goo
C5)
Cop
65405)
G9o9
Go 365
2,365 "2, 365¢2,365