Urinalysis. Urine sampling provides useful information about the amount of
plutonium excreted following an intake. After chemical isolation, the plutonium in
urine samples may be determined by various methods including: alpha spectrometry
(gas-flow proportional or surface-barrier detection), alpha counting (zinc sulfide or
liquid scintillation counting), fission track counting, and mass spectrometry.
Analytical procedures for in vitro measurement of plutonium and other radionuclides
have been published (Volchok and dePlanque, 1983; Gautier, 1983).
Urine samples should be collected away from the plutonium facility to minimize
cross-contamination. Samples should be collected in contamination-free containers;
measures should be considered for minimizing plateout on walls of container surfaces
(such as by addition of trace amounts of gold, oxalate, or nitric acid).
Fecal Analysis. Fecal analysis is a useful procedure for evaluating the excretion of
plutonium and many other radioactive materials because more than half of the
material deposited in the upper respiratory tract is cleared rapidly to the stomach and
gastrointestinal (GI) tract.
The total fecal plus urinary elimination for the first few days after exposure,
combined with in vivo counts that might be obtained, may provide the earliest and
most accurate assessment of intake. Fecal samples taken during the second and third
day after an inhalation incident are likely to provide the most useful data because the
gastrointestinal hold-up time may vary from a few hours to a few days.
Fecal sampling is primarily a monitoring procedure for confirming and evaluating
suspected intakes, but is used at some plutonium facilities for routine periodic
monitoring as well. Workers may find fecal sampling unpleasant or objectionable,
and laboratory technicians may also have aversion to fecal sample analysis. Some of
these problems may be minimized if commercial fecal sample collection kits are used
for convenient collection and handling of samples (Fisher et al., 1982). Collection
kits also provide a means for collecting uncontaminated samples. Fecal samples may
require additional sample preparation before analysis.
ESTABLISHING BIOASSAY FREQUENCY
The bioassay measurement frequency should be based on 1) the potential risks of an intake
occurring and 2) the sensitivity of a bioassay program to detecting potential intakes. The
bioassay program sensitivity can be selected using specified intervals between
measurements based on the MDD associated with an interval.