BLOOD STYRENE CONCENTRATIONS IN A NORMAL POPULATION AND IN EXPOSED WORKERS 16 HOURS AFTER THE END OF THE WORKSHIFT

Blood styrene was measured by a gas chromatography-mass spectrometry m ethod in 81 ''normal people'' and in 76 workers exposed to styrene. In the normal subjects, styrene was also tested in alveolar and environm ental air. Styrene was found in nearly all (95%) blood samples. Averag e styrene levels in the normal subjects were 221 ng/l in blood (Cb), 3 ng/l in alveolar air (Ca) and 6 ng/l in environmental air (Ci). Styre ne levels did not differ significantly between smokers and nonsmokers, 95% of values being below 512 ng/l in Cb, 7 ng/l in Ca and 15 ng/l in Ci. In workers with an average exposure to styrene of 204 mug/l, at t he end of the workshift, mean blood styrene concentration was 1211 mug /l. In blood samples collected at the end of the Thursday shift, styre ne levels were significantly higher (1590 mug/l) than those found at t he end of the Monday shift (1068 mug/l). A similar difference was foun d in samples taken the morning after exposure (60 and 119 mug/l, respe ctively). Significant correlations between blood and environmental sty rene were found both at the end of the shift and the morning after exp osure (r = 0.61 and 0.41, respectively). In workers occupationally exp osed to styrene, 16 h after the end of the workshift, blood styrene (9 4 mug/l) was significantly higher than that found in the normal subjec ts (0.22 mug/l). The half-life of blood styrene was 3.9 h.