HEMOGLOBIN ADDUCTS AS BIOMARKERS OF OCCUPATIONAL EXPOSURE TO 1,3-BUTADIENE

Adducts of 1,2-epoxy-3-butene (EB) with haemoglobin were monitored in 17 workers from the 1,3-butadiene (ED) production unit of a petrochemi cal plant and in nine referents employed at the same factory but not e xposed to ED. The air concentrations of ED were determined using stati onary and personal monitoring, The ambient level of exposure of the pl ant workers handling butadiene containers (sampling and voiding) was o n average 11.2 +/- 18.6 (mean +/- SD) mg/m(3), Maintenance and laborat ory workers were exposed to levels less than or equal to 1.2 mg/m(3). The particular haemoglobin adduct measured was 2-hydroxy-3-butenylvali ne, formed by reaction of N-terminal valine with carbon 1 in EB, The a dduct levels were increased (0.16 +/- 0.099 pmol/g; n = 10) in plant w orkers compared with the levels in maintenance and laboratory workers and controls (similar to 0.05 pmol/g; seven laboratory workers and min e controls evaluated). Thus, the method used for adduct determination- derivatization of 200-300 mg globin samples with pentafluorophenyl iso thiocyanate according to the nr-alkyl Edman method and detection of th e thiohydantoin derivatives by tandem mass spectrometry-is sufficientl y sensitive to allow monitoring of exposure to ED down to the p.p.m. l evel.