Excreta Sampling as an Alternative to In Vivo Measurements at the Hanford Site

Area of Science:

• Occupational health physics
• Internal radiation dosimetry
• Bioassay methods

Background:

• Hanford workers face potential exposure to various radionuclides.
• Accurate monitoring is essential for worker safety and regulatory compliance.
• Direct radiobioassay (in vivo) and indirect radiobioassay (ex vivo) are established monitoring techniques.

Purpose of the Study:

• To compare the effectiveness of indirect radiobioassay (urine/fecal analysis) with direct radiobioassay (whole body/lung counting).
• To evaluate monitoring capabilities for common radionuclides and exposure scenarios at the Hanford Site.
• To determine the suitability of indirect methods as a contingency for direct monitoring.

Main Methods:

• In vivo measurements (whole body counting, lung counting) for radionuclides like 137Cs, 60Co, 154Eu, and 241Am.
• Indirect analysis of urine and fecal samples using gamma energy analysis, radiochemistry, and alpha spectrometry.
• Comparison of detection limits, sensitivity, and practical application for Hanford worker scenarios.

Main Results:

• In vivo methods provide comprehensive monitoring for the studied radionuclides.
• Indirect methods (urine/fecal analysis) can detect the same radionuclides but with reduced sensitivity and specificity.
• Indirect methods are a feasible, albeit degraded, short-term alternative for monitoring.

Conclusions:

• Direct radiobioassay (whole body and lung counting) must be maintained at the Hanford Site.
• Indirect radiobioassay offers a supplementary or alternative monitoring strategy.
• Urine and fecal sample analysis can serve as a critical short-term fallback if direct monitoring is compromised.