Bioassays in workers exposed to long time random intakes

Area of Science:

• Occupational health and safety
• Radiological protection
• Internal contamination monitoring

Background:

• Occupational exposure to radioactive aerosols necessitates internal contamination monitoring via bioassays and air sampling.
• Traditional methods often assume chronic, constant exposure, which doesn't reflect random intake patterns and non-exposure periods.

Purpose of the Study:

• To develop and apply a novel method for estimating radioactive intakes, considering random exposure events and non-exposure periods.
• To evaluate the accuracy of current intake estimation methods and identify potential discrepancies in worker monitoring.
• To assess the applicability of standard biokinetic models for individual workers.

Main Methods:

• Utilized simulations to optimize evaluation methods for minimizing statistical uncertainties in intake estimation.
• Applied the new method to long-term exposed workers (30+ years) in uranium dioxide (UO2) aerosol sintering areas.
• Employed the International Commission on Radiological Protection's (ICRP) new Occupational Intakes of Radionuclides (OIR) biokinetic models for uranium, solved using the BIOKMOD code.

Main Results:

• Significant deviations were observed between uranium intake estimates derived from urine bioassays and Static Air Samples (SAS) for some workers.
• The findings challenge the universal applicability of standard physiological parameters for reference workers in biokinetic modeling.
• The BIOKMOD code facilitated the implementation and analysis of these complex biokinetic models.

Conclusions:

• The developed method provides a more realistic assessment of occupational radioactive intake by accounting for exposure variability.
• Individual worker data may necessitate adjustments to standard biokinetic models, improving the accuracy of internal contamination assessments.
• This approach enhances the reliability of radiological protection programs for occupationally exposed individuals.