Fecal Analysis

DOE-STD-1136-2004

Guide of Good Practices for Occupational Radiological Protection in Uranium Facilities

spectrometry (gas-flow proportional or surface-barrier detection), alpha counting (zinc sulfide or liquid

scintillation counting), or track counting. Analytical procedures for in vitro measurement of uranium and

other radionuclides have been published (Volchok and dePlanque 1983; Gautier 1983).

Urine samples should be collected away from the uranium 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 uranium 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 uranium 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. Collection kits also provide a means for collecting

uncontaminated samples. Fecal samples may require additional sample preparation before analysis.

5.4 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.

The rationale for the selected bioassay measurement frequency should also be documented. It is

appropriate to evaluate the probability of intake and to modify the sampling frequency based on that

The frequency of bioassay measurements should normally not be decreased because analytical results

are below the detection level. The bioassay program should be maintained to confirm the proper

functioning of the overall internal exposure control program and to document the absence of significant

intakes of radionuclides.

5.4.1

Frequency Based on Program Sensitivity

The minimum detectable dose concept refers to the potential dose associated with an MDA bioassay

measurement at a given time interval post-intake. The pattern of retention of activity in the body, the MDA

for a bioassay measurement technique, and the frequency with which that technique is applied define a

quantity of intake that could go undetected by the bioassay program. An intake of such a

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