Monitoring Exposure to Organic Compounds: One of the goals of our Center is to develop and lead the characterization of environmental exposures for epidemiologic studies of health effects in environmental and occupational settings, and especially the investigation of the relationship between environmental exposure and internal dose.  Dr. Smith has been conducting a laboratory exposure study of human metabolism of 1,3-butadiene (BD), which is activated to epoxides by CYP2E1 enzyme which has genetic polymorphisms, and it is detoxified by glutathione-S-transferases.  BD is a very common urban air toxic pollutant which causes cancers in rats and mice, and is a probable human carcinogen.  In his lab, uptake and washout of very small amounts of inhaled BD are observed for each volunteer using an approved human subjects protocol.  Over 200 subjects have been tested.  These data are fitted with a toxicokinetic model to estimate each subject's personal rate of metabolism (Mezzetti, Ibrahim et al. 2003).  Each subject has been exposed to exactly the same amount of BD - 2 ppm for 20 min.  However, significant differences have been seen in uptake by gender, age, and blood lipids.  Dr. Smith is applying these research techniques developed for BD to other toxic materials.