Determination of isocyanate biomarkers in construction site workers.
4,4'-Methylenediphenyl diisocyanate (MDI) is the most important isocyanate in the manufacture of polyurethanes, dyes, pigments and adhesives. High concentrations of isocyanates are a potent respiratory irritant. Therefore, it is important to develop methods to monitor exposure to such compounds. We monitored biological samples from 40 non-exposed and 45 exposed construction site workers. 4,4'-Methylenedianiline (MDA) and N-acetyl-4,4'-MDA (AcMDA) were determined from untreated urine (U-MDA, U-AcMDA) and MDA was analysed from acid-treated urine (U-MDA-tot). Haemoglobin (Hb) adducts of MDA (Hb-MDA) were determined in all workers. The levels of biomarkers decreased in the following order: U-MDA-tot>U-AcMDA>U-MDA>Hb-MDA. The same order was found for the percentage of samples, which were found positive in exposed workers: 100%, 91%, 91%, 27%. The urine levels U-MDA-tot correlate with U-MDA, U-AcMDA and Hb-MDA with r=0.79, 0.86 and 0.39, respectively (Spearman rank order, p<0.01). U-AcMDA correlates with U-MDA and Hb-MDA with r=0.77 and 0.47, respectively (p<0.01). U-MDA correlates with Hb-MDA (r=0.38, p<0.05). The levels in the controls were significantly lower than in the exposed workers for all compounds (Mann-Whitney test, p<0.01). The median isocyanate-specific IgE-level was higher in the exposed workers, but the difference was statistically not significant. The change of the biomarker levels was compared in a group of workers (n=20), which were analysed prior to isocyanate exposure and after the exposure for approximately 4-7 months. All urine MDA metabolites and the Hb-adduct levels increased significantly (Wilcoxon sign test, p<0.01). Total IgE increased significantly after the exposure with isocyanate activity (p<0.01). With the present work it could be shown that outdoor workers are exposed to a similar extent as workers from a MDI factory.
Sabbioni
Gabriele
G
Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA 70112, USA. gabriele.sabbioni@bluewin.ch
Wesp
Hansjörg
H
Lewalter
Jürgen
J
Rumler
Richard
R
D000083:Acetanilides / Q000652:urine; D000328:Adult; D000814:Aniline Compounds / Q000652:urine; D015415:Biomarkers / Q000652:urine*; D003252:Construction Materials / Q000009:adverse effects; D004784:Environmental Monitoring / Q000379:methods*; D005260:Female; D006454:Hemoglobins / Q000032:analysis / Q000378:metabolism; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D017953:Isocyanates / Q000276:immunology / Q000378:metabolism / Q000652:urine*; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects / Q000032:analysis* / Q000517:prevention & control; D012621:Seasons; D011795:Surveys and Questionnaires; D014051:Toluene 2,4-Diisocyanate / Q000276:immunology; D001559:Benzhydryl Compounds
D000083:Acetanilides; D000814:Aniline Compounds; D015415:Biomarkers; D006454:Hemoglobins; D007073:Immunoglobulin E; D017953:Isocyanates; D014051:Toluene 2,4-Diisocyanate; C025319:phenyl isocyanate; C050075:N-acetyl-4,4'-diaminodiphenylmethane; C005969:4,4'-diphenylmethane diisocyanate; D001559:Benzhydryl Compounds; C009505:4,4'-diaminodiphenylmethane