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 has produced further evidence that benzene oxide (BO) is a major binding species resulting from metabolism of benzene both in rats and humans. Project scientists have also confirmed that S-phenylcysteine, isolated from proteins in benzene exposed animals and humans, did indeed arise from reaction of BO with cysteinyl residues of the proteins. The investigators have shown that adducts of BO with the blood proteins, hemoglobin and albumin, were both related to benzene exposures among heavily exposed Chinese workers as were albumin (but not hemoglobin) adducts of 1,4-benzoquinone, another benzene metabolite. These latter findings arose from a collaboration with Dr. Nathaniel Rothman of the National Cancer Institute, who is conducting a major epidemiological investigation of benzene-exposed workers in China. This project has also confirmed that rodent microsomes do indeed produce chlorinated 1,2- and 1,4-quinone metabolites of pentachlorophenol and that peroxidase plus H2O2 leads to chlorinated semiquinone intermediates of these quinones. Finally, this project has shown that a simple self-administered test kit can be used to explore relationships between benzene exposure and breath levels of benzene in populations exposed to gasoline and jet fuels.