Biological monitoring of occupational exposure to low levels of benzene

Abstract

To obtain reference values for the biological monitoring of benzene, the kinetics of benzene were studied in volunteers. Benzene in blood and expired air could easily be followed until the next morning after a 4-h exposure to a benzene concentration of 10 cm3 m-3. Even after exposure to 1.7 cm3 m-3 the benzene levels in the morning blood and expired air samples differed from those in unexposed subjects. One hour after exposure to 10 and 1.7 cm3 m-3 the mean levels of benzene were 238 and 25 nmol l-1 in blood and 13.2 and 2.5 μmol m-3 in exhaled air, respectively. It was concluded that, at high benzene levels (~10 cm3 m-3), samples collected 16h after exposure reflect the body burden of benzene, while at low exposure (<1 cm3 m-3) samples collected 1h after exposure may be used to estimate the exposure over the preceding few hours. Exposure to benzene from smoking is a potential confounder in estimating occupational exposure to low levels of benzene.