Biological Markers of Exposure to Benzene

EPA Grant Number: R826249
Title: Biological Markers of Exposure to Benzene
Investigators:
Institution: Lovelace Respiratory Research Institute
EPA Project Officer: Chung, Serena
Project Period: March 20, 1998 through March 19, 2001
Project Amount: $471,696
RFA: Ambient Air Quality (1997) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Air

Description:

Benzene is a ubiquitous airborne toxicant; to improve human health risk assessment for benzene exposure, better assessment of human exposure to benzene is needed. Biological markers provide a direct and objective means of monitoring the total exposure of individuals to specific chemicals. Biological markers of exposure may include the presence of volatile organic compounds in the exhaled air, organic compounds or their metabolites in blood or urine, adducts formed with macromolecules such as nucleic acids or proteins, and breakdown products of such adducts that appear in the urine. Some of these markers indicate more recent exposure (e.g., parent compound in exhaled air), while others are markers of more distant exposure (e.g., hemoglobin adducts). Our objective is to relate the level of the markers in the body in a quantitative manner to prior exposures. It is our hypothesis that the use of a panel of exposure markers, including markers of both recent and earlier exposure, is an effective strategy for relating current levels of biomarkers of exposure to prior exposures. A person who had been exposed to benzene, but not recently, will display markers with long half lives, but no short half-life markers will be present. If both short and long half-life markers are present, but the levels of the longer half-life markers are quite low, the individual has been exposed recently. If the level of the longer half-live markers is relatively high compared to the short half-life markers, the individual must have been exposed for an extended period of time.

Approach:

The half-lives of six biological markers of exposure to benzene will be determined in an animal model (the B6C3F1mouse); a physiologically-based pharmacokinetic model will be developed that can predict the level of the different markers following different exposure scenarios in a quantitative fashion. The model will be modified for human physiological parameters and the model tested in humans exposed to known amounts of benzene. The six biomarkers of benzene exposure to be measured, in order of increasing expected half-lives, will be benzene in exhaled breath, benzene in blood, phenylmercapturic acid and muconic acid in urine, phenylcysteine adducts on blood albumin and phenylcysteine adducts on hemoglobin.

Expected Results:

The utility of multiple markers for assessing prior exposures to benzene will be determined. A battery of biomarkers rather than a single biomarker should provide risk assessors and managers with a more complete picture of the pattern of both recent and prior exposures to chemicals and will lead to better informed decisions in regard to health risks associated with exposure to that chemical.

Publications and Presentations:

Publications have been submitted on this project: View all 7 publications for this project

Supplemental Keywords:

exposure, chemical, VOC, air, water, modeling, monitoring, risk., Health, Scientific Discipline, Air, Toxics, air toxics, Environmental Chemistry, Health Risk Assessment, Epidemiology, HAPS, Risk Assessments, Biochemistry, Atmospheric Sciences, ambient air quality, monitoring, risk assessment, blood samples, animal model, ambient monitoring, benzene, air sampling, human exposure, inhalation, urine and blood samples, biocontaminants, half-life markers, Benzene (including benzene from gasoline), biological markers, Volatile Organic Compounds (VOCs), human health

Progress and Final Reports:

  • 1998
  • 1999 Progress Report
  • Final Report