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: Heiko Udo Käfferlein, Horst Christoph Broding, Jürgen Bünger, Birger Jettkant, Stephan Koslitz, Martin Lehnert, Eike Maximilian Marek, Meinolf Blaszkewicz, Christian Monsé, Tobias Weiss, Thomas Brüning
• Journal: Archives of toxicology (Arch Toxicol) Vol. 88 Issue 7 Pg. 1419-26 (Jul 2014) ISSN: 1432-0738 [Electronic] Germany
• PMID: 24899222 (Publication Type: Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Aniline Compounds
• Methemoglobin
• aniline

Topics

• Adult
• Aniline Compounds (administration & dosage, toxicity, urine)
• Female
• Humans
• Male
• Methemoglobin (metabolism)
• Methemoglobinemia (chemically induced, prevention & control)
• Middle Aged
• Occupational Diseases (prevention & control)
• Occupational Exposure (prevention & control)
• Pilot Projects
• Risk Assessment (methods)
• Sex Factors
• Time Factors
• Young Adult