Uncertainties Associated with Preliminary Evaluations

DOE-STD-1121-98

Table X. Comparison of Methods of Assessing Dose from Intakes of Radionuclides

Method

Type

Accuracy

Precision

Sensitivity

Cost

H urinalysis

Bioassay

High

Low

239

Pu urinalysis

Bioassay

Moderate

Low

Very low

High

239

Pu air monitoring

Air monitoring

Very low

Moderate

Radon progeny air

Air monitoring

Moderate

monitoring

7.7.1 Uncertainties Associated with Preliminary Evaluations

Preliminary dose evaluations, when based on bioassay data obtained within the first few days of an

intake by inhalation, may be very uncertain. It is not uncommon for such preliminary evaluations to be

wrong by a factor of 10 either direction. It is thus very important not to overreact to initial dose

assessments, which may be revised either upward or downward when bioassay data over a period of

weeks or months become available.

7.7.2 Uncertainties Associated with Final Evaluations

Even when all bioassay data are consistent with a plausible biokinetic model, in many cases there are

still significant uncertainties in doses assessed from bioassay data. This is especially true of intakes of

actinides and doses from intakes of unknown time course and unknown physical and chemical form. For

significant intakes, it is desirable, although not always feasible, to quantify and document the uncertainty

associated with a final dose assessment.