MONITORING OCCUPATIONAL EXPOSURE TO STYRENE FROM HEMOGLOBIN ADDUCTS AND METABOLITES IN BLOOD

Monitoring occupational exposure to styrene was achieved through quant ification of adducts of styrene 7,8-oxide to N-terminal valine in hemo globin (Hb) on the basis of the enrichment of adducted globin chains b y ion-exchange chromatography and gas chromatographic-mass spectrometr ic analysis by the use of the N-alkyl Edman method. Application to blo od samples from reinforced plastics workers exposed to styrene and fro m referents showed Hb adduct levels correlating with the blood styrene glycol and urinary mandelic acid concentrations. The blood styrene gl ycol and styrene 7,8-oxide levels of the exposed workers averaged 2.5 mumol . l-1 (17 subjects) and 0.09 mumol . l-1 (7 subjects), respectiv ely. The blood styrene glycol and urinary mandelic acid content (mean 9.5 mmol . l-1, 17 subjects) suggested a styrene concentration of abou t 300 mg . m-3 (75 ppm) in the workplace air. The Hb adduct levels wer e low (mean 28 pmol . g-1), indicating rapid detoxification of styrene 7,8-oxide in humans.