X. = the number of radioactive atoms in compartment i relative to the number in
all compartments on the day of return (some persons returned with body
burdens),
U
= twenty-four hour or one liter urine activity concentration at any time post
,
‘
~-1
i)
.
subject urine excretion rate, &%d
ut
.
-1
fraction of element transferred from GI tract to blood,
um
rh
mh
a
return, Bq 2
6,
fraction of element reaching extracellular fluid that is excreted through
the urine pathway,
k
= instantaneous fraction of atoms removed from the atom ingestion rate per
unit time, at, due to factors other than radioactive decay,
q
= body burden at any time post return, Bq,
q
= body burden on the day of return, Bq.
Using adult average data,
two consecutive urine or body-burden measure-
ments were used to estimate the unknown value of k, a rate constant describing
removal of radioactivity in diet items.
This yielded n-1l estimates of k where
nm was the number of measured adult average data points for body burden or urine
activity concentration during the residence interval.
An average value of k was
assigned for the entire residence interval during which activity was measured.
After the average k was obtained, an estimate of the atom ingestion rate on day
of return was calculated based on a value for adult average body burden or urine
activity concentration and the time since day of return.
This generated n
values of the atom ingestion rate on day of return where n was again the number
of adult average data points for body burden or urine activity concentration.