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INTERPRETATION OF BENZENE URINARY BIOMARKER DATA FOR RISK ASSESSMENT: A CASE STUDY
Citation:
ARNOLD, S. M., P. S. PRICE, M. F. HUGHES, AND S. H. ROBISON. INTERPRETATION OF BENZENE URINARY BIOMARKER DATA FOR RISK ASSESSMENT: A CASE STUDY . Presented at Society of Toxicology Annual Meeting, Seattle, WA, March 16 - 20, 2008.
Impact/Purpose:
The Biomonitoring Technical Committee of the ILSI Health and Environmental Sciences Institute is developing a case study of the relationship of human biomarker data to risk.
Description:
Human biomonitoring is an effective tool in assessing exposure to hundreds of chemicals. Too often, however, biomarkers such as parent or metabolite concentrations in blood or urine are reported without information on doses associated with the biomarkers and implications for human risk. The Biomonitoring Technical Committee of the ILSI Health and Environmental Sciences Institute is developing a case study of the relationship of human biomarker data to risk. The committee selected benzene as an example, but the goal is to develop an approach applicable to other chemicals. Historically, urinary phenol was used to determine occupational exposure to benzene. However, phenol was not specific for benzene exposure due to high dietary background levels. Therefore, as workplace benzene concentrations have decreased (< 1 ppm) in the U.S. and Europe, the use of urinary phenol has been replaced by measurements of urinary S-phenylmercapturic acid (SPMA) or t,t-muconic acid (MA). SPMA is a specific biomarker for benzene; however, conversion from benzene is low (≤ 0.3%), and MA is confounded by dietary sorbic acid ingestion. Biomarkers are also of interest for the general population who have exposures < 0.01 ppm. This poster evaluates the current literature to define the lower limits of occupational and environmental air benzene concentrations that can be reliably characterized using urinary metabolites (SPMA, MA, phenol, catechol, hydroquinone), urinary benzene, and blood benzene. Critical factors evaluated are the stoichiometric relationships between inhalation exposure and biomarker concentrations, the logistics of sample collection, analytical issues (e.g., method, detection limit, sensitivity, etc.), and potential background exposure sources of the biomarkers (e.g., smoking, diet, pharmaceuticals, etc.). This abstract does not represent USEPA policy.