title: Human exposure to airborne aniline and formation of methemoglobin: a contribution to occupational exposure limits.
abstract: Aniline is an important starting material in the manufacture of polyurethane-based plastic materials. Aniline-derived methemoglobinemia (Met-Hb) is well described in exposed workers although information on the dose-response association is limited. We used an experimental design to study the association between aniline in air with the formation of Met-Hb in blood and the elimination of aniline in urine. A 6-h exposure of 2 ppm aniline in 19 non-smoking volunteers resulted in a time-dependent increase in Met-Hb in blood and aniline in urine. The maximum Met-Hb level in blood (mean 1.21 ± 0.29 %, range 0.80-2.07 %) and aniline excretion in urine (mean 168.0 ± 51.8 µg/L, range 79.5-418.3 µg/L) were observed at the end of exposure, with both parameters rapidly decreasing after the end of exposure. After 24 h, the mean level of Met-Hb (0.65 ± 0.18 %) returned to the basal level observed prior to the exposure (0.72 ± 0.19 %); whereas, slightly elevated levels of aniline were still present in urine (means 17.0 ± 17.1 vs. 5.7 ± 3.8 µg/L). No differences between males and females as well as between slow and fast acetylators were found. The results obtained after 6-h exposure were also comparable to those observed in four non-smoking volunteers after 8-h exposure. Maximum levels of Met-Hb and aniline in urine were 1.57 % and 305.6 µg/L, respectively. Overall, our results contribute to the risk assessment of aniline and as a result, the protection of workers from aniline-derived adverse health effects at the workplace.
authors.affiliation: Institute for Prevention and Occupational Medicine of the German Social Accident Insurance, Institute of the Ruhr University Bochum (IPA), Bürkle-de-la-Camp Platz 1, 44789, Bochum, Germany, kaefferlein@ipa-dguv.de.
authors.forename: Heiko Udo
authors.initials: HU
authors.lastname: Käfferlein
authors.forename: Horst Christoph
authors.initials: HC
authors.lastname: Broding
authors.forename: Jürgen
authors.initials: J
authors.lastname: Bünger
authors.forename: Birger
authors.initials: B
authors.lastname: Jettkant
authors.forename: Stephan
authors.initials: S
authors.lastname: Koslitz
authors.forename: Martin
authors.initials: M
authors.lastname: Lehnert
authors.forename: Eike Maximilian
authors.initials: EM
authors.lastname: Marek
authors.forename: Meinolf
authors.initials: M
authors.lastname: Blaszkewicz
authors.forename: Christian
authors.initials: C
authors.lastname: Monsé
authors.forename: Tobias
authors.initials: T
authors.lastname: Weiss
authors.forename: Thomas
authors.initials: T
authors.lastname: Brüning
mesh_terms: D000328:Adult; D000814:Aniline Compounds / Q000008:administration & dosage* / Q000633:toxicity / Q000652:urine; D005260:Female; D006801:Humans; D008297:Male; D008706:Methemoglobin / Q000378:metabolism*; D008708:Methemoglobinemia / Q000139:chemically induced / Q000517:prevention & control; D008875:Middle Aged; D009784:Occupational Diseases / Q000517:prevention & control*; D016273:Occupational Exposure / Q000517:prevention & control*; D010865:Pilot Projects; D018570:Risk Assessment / Q000379:methods; D012737:Sex Factors; D013997:Time Factors; D055815:Young Adult
chemical_list: D000814:Aniline Compounds; D008706:Methemoglobin; C023650:aniline