Superfund Research Program
Development and Application of Biomarkers of Exposure
Project Leader: Stephen M. Rappaport (University of California-Berkeley)
Grant Number: P42ES005948
Funding Period: 1995 - 2011
This project focuses on biomarkers of exposure to benzene, a known carcinogen of humans and animals. The biomarkers include protein adducts of several toxic metabolites of benzene and of benzene in breath and urine and of benzene metabolites in urine. Using these biomarkers, project investigators are evaluating the metabolism of benzene over a wide range of human exposures in samples of blood, urine, and breath obtained by collaborators at other institutions and in prior studies. A method has been developed to measure benzene metabolites in urine which is currently being applied to 300 workers from Tianjin, China. Researchers also explored the relationships between albumin adducts of two reactive benzene metabolites, benzene oxide and 1,4-benzoquinone among 185 workers in Tianjin, China. The transition from linear to saturable metabolism began at about one ppm, a level much lower than previously thought. Adduct levels were generally lower in older workers, indicating that CYP 2E1 metabolism diminished with age, at about 2% per year of life.