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Biological exposure indicators: quantification of biological variability using toxicokinetic modeling
Ginette Truchon1, Robert Tardif, Pierre-Olivier Droz
1Institut de recherche Robert-Sauvé en santé et en sécurité du travail, Montréal, Québec, Canada. truchon.ginette@irsst.qc.ca
Journal of Occupational and Environmental Hygiene
|February 9, 2006
Summary
Biological variability significantly impacts bio-indicators for chemical exposures. Unchanged substances are less variable than metabolites, with airflow and cardiac output being key factors influencing absorbed doses.
Area of Science:
- Environmental toxicology
- Toxicokinetics
- Computational toxicology
Background:
- Biological variability influences individual responses to chemical exposures.
- Understanding this variability is crucial for accurate risk assessment.
- Existing models often simplify interindividual differences.
Purpose of the Study:
- To quantify the impact of biological variability on bio-indicators of industrial chemical exposures.
- To identify key physiological and biochemical parameters driving this variability.
- To compare variability in measurements of parent compounds versus metabolites.
Main Methods:
- Utilized compartmental and physiologically based toxicokinetic modeling.
- Employed Monte Carlo simulation to assess parameter uncertainty.
- Analyzed bio-indicators for metal and organic chemical exposures.
Main Results:
- Demonstrated significant interindividual variability across different bio-indicator categories.
- Found measurements of unchanged substances (blood, urine, air) to be less variable than metabolites.
- Identified alveolar airflow and cardiac output as primary drivers of biological variability.
Conclusions:
- Biological variability significantly affects bio-indicator values for chemical exposures.
- Workload intensity, reflected by alveolar flow and cardiac output, is critical for absorbed dose in inhaled chemicals.
- Differentiating between parent compound and metabolite measurements is important for interpreting variability.
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