title: Workers exposed to thermal degradation products of TDI- and MDI-based polyurethane: biomonitoring of 2,4-TDA, 2,6-TDA, and 4,4'-MDA in hydrolyzed urine and plasma.
abstract: The aim of the study was to investigate biomarkers of exposure to thermal degradation products of 2,4- and 2,6-toluene diisocyanate (TDI)- and 4,4'-methylenediphenyl diisocyanate (MDI)-based polyurethane and the toxicokinetics of these products. Blood and urine were collected from 15 factory workers exposed to thermal degradation products of MDI-based polyurethane glue and TDI-based flexible foam. Four of these workers were also studied during an exposure-free period. Urine and plasma were analyzed after acidic hydrolysis and the concentrations of the isocyanates' corresponding amines, 2,4-, 2,6-toluenediamine (TDA), and 4,4'-methylenedianiline (MDA), were determined as derivatives of pentafluoropropionic anhydride by gas chromatography using chemical ionization mass spectrometry monitoring negative ions. Urinary elimination rates were in the range of < 0.01-5.7 micrograms of 2,4-TDA per hour, < 0.01-3.5 micrograms of 2,6-TDA per hour, and < 0.01-1.6 micrograms of 4,4'-MDA per hour. Plasma levels were in the range of < 0.1-5.5 ng of 2,4-TDA per mL, < 0.1-2.3 ng of 2,6-TDA per mL, and < 0.1-45 ng of 4,4'-MDA per mL. The urinary half-lives of 4,4'-MDA for four of the workers were found to be 59, 61, 73, and 82 hours. The half-lives of 4,4'-MDA in plasma were 10, 14, 16, and 22 days. Elimination rate peaks of 2,4-TDA, 2,6-TDA, and 4,4'-MDA in urine varied during and between workdays. The individual variation in plasma concentrations of 2,4-TDA, 2,6-TDA, and 4,4'-MDA with time was small, but between individuals the variation was great.
authors.affiliation: Department of Occupational and Environmental Medicine, University Hospital, Lund, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Dalene
authors.forename: G
authors.initials: G
authors.lastname: Skarping
authors.forename: P
authors.initials: P
authors.lastname: Lind
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000814:Aniline Compounds / Q000378:metabolism*; D001336:Automobiles; D015415:Biomarkers; D002273:Carcinogens / Q000378:metabolism*; D005260:Female; D006801:Humans; D008657:Metabolic Clearance Rate; D016273:Occupational Exposure / Q000032:analysis*; D011140:Polyurethanes / Q000737:chemistry*; D013548:Sweden; D014051:Toluene 2,4-Diisocyanate / Q000378:metabolism*; D001559:Benzhydryl Compounds
chemical_list: D000393:Air Pollutants; D000814:Aniline Compounds; D015415:Biomarkers; D002273:Carcinogens; D011140:Polyurethanes; D014051:Toluene 2,4-Diisocyanate; C009505:4,4'-diaminodiphenylmethane; D001559:Benzhydryl Compounds