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DOSE RECONSTRUCTION FROM URINARY BIOMARKERS
Citation:
Okino, M S. AND J J. Quackenboss. DOSE RECONSTRUCTION FROM URINARY BIOMARKERS. Presented at Biomarkers: Taking Stock EPA/NIEHS Workshop on Applying Biomarker Research, Chapel Hill, NC, August 30-31, 1999.
Description:
The use of biomarkers for human health risk assessment is attractive because they are an indicator of the dose that actually entered the body by all mechanisms. This is an important consideration given the need to include aggregate exposures from diet and other pathways for pesticides. Quantitative relationships between biomarker and environmental concentrations are often unclear, because what is seen in a urine sample depends on the route and time-profile of the exposure. Pharmacokinetic (PK) models describe the dynamics of the chemical in the body. By inverting the appropriate mathematical expressions, the absorbed dose can be calculated from the concentration of the parent compound or a metabolite in a spot urine sample. The goal of this paper is to review the assumptions used in interpreting urinary biomarkers and highlight the role of PK models in reconstructing dose from spot urine measurements. We will demonstrate the estimation method and the impact of different exposure scenarios on interpretation of the biomarker measurement.
This work has been funded wholly or in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication.