Adaptation to Occupational Exposure to Moderate Endotoxin Concentrations: A Study in Sewage Treatment Plants in Germany

  • M. A. RiegerEmail author
  • V. Liebers
  • M. Nübling
  • T. Brüning
  • B. Brendel
  • F. Hoffmeyer
  • M. Raulf
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 1116)


Acute or chronic inhalation of endotoxin may lead to changes of lung function and inflammatory markers in the airways. Adaptation to workplace exposure may be possible. In this study, we investigated the possible difference in inflammatory markers assessed in nasal lavage fluid (NALF) in chronical exposure compared to voluntary subjects exposed acutely to endotoxin. We sought to define the variability of inflammatory markers in NALF and the dose-related changes after moderate exposure in naïve subjects. Endotoxin exposure (4–1039 EU/m3) resulted from routine work during one shift in sewage treatment plants. Subjects were matched to pairs (8 workers escorted by 10 students). Inflammatory markers were investigated before, directly after, and 16 h after the shift end. Additional NALF samples were collected in students without any specific exposure after 3 days. In NALF, total cell count, and interleukin (IL)-8 and IL-1β concentrations were significantly higher in workers than in students at all times pointing to workplace-related long-lasting exposure resulting in adaptation. However, concentration of inflammatory markers without specific exposure in students showed a great variability, covering the whole range of values recorded in the workers. The findings of this study make us to recommend a repeated assessment of inflammatory markers in healthy volunteers before the investigation of exposure-related changes and a sample size adequate for statistical analysis.


Cumulative effect Dose-response relationship Endotoxin exposure Inflammation Nasal lavage fluid Occupational exposure Sewage 



The study was financed by a grant of the Lieselotte und Dr. Karl Otto Winkler Stiftung für Arbeitsmedizin and own research funds of the institutions involved (Department of Applied Physiology, Occupational Medicine and Infectiology, University of Wuppertal, Germany, and Department of Allergology/Immunology, Institute for Prevention and Occupational Medicine, Institute of the German Social Accident Insurance, Ruhr University Bochum, Germany). The work of the Institute of Occupational and Social Medicine and Health Services Research (IASV) is supported by an unrestricted grant of the employers’ association of the metal and electric industry Baden-Württemberg (Südwestmetall).

The authors thank the Emscher-Genossenschaft/Lippeverband (EGLV) for giving access to their sewage treatment plants, all volunteers for study participation, and the involved staff of IPA, IASV, and University Wuppertal, especially Monika Lahr, Heiko Diefenbach, and Nicole Blomberg for technical assistance in collection of specimens and on the sewage treatment plants and Gerda Borowitzki, Susanne Freundt, and Sabine Bernard for technical assistance in analysis of the NALF samples.

Conflicts of Interest

The authors declare no conflicts of interest in relation to this article.


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Copyright information

© Springer Nature Switzerland AG 2018

Authors and Affiliations

  • M. A. Rieger
    • 1
    Email author
  • V. Liebers
    • 2
  • M. Nübling
    • 3
  • T. Brüning
    • 2
  • B. Brendel
    • 4
  • F. Hoffmeyer
    • 2
  • M. Raulf
    • 2
  1. 1.Institute of Occupational and Social Medicine and Health Services ResearchUniversity Hospital of TübingenTübingenGermany
  2. 2.Institute for Prevention and Occupational Medicine of the German Social Accident Insurance (IPA)Ruhr University BochumBochumGermany
  3. 3.Research Center for Occupational and Social Medicine (FFAS)FreiburgGermany
  4. 4.Institute for Clinical Epidemiology and Applied BiometryTübingen University HospitalTübingenGermany

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