Adaptation to Occupational Exposure to Moderate Endotoxin Concentrations: A Study in Sewage Treatment Plants in Germany
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.
KeywordsCumulative 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.
- BGIA-Arbeitsmappe (1989) Verfahren zur Bestimmung der Endotoxinkonzentration in der Luft am Arbeitsplatz (Kennzahl 9450). In: Berufsgenossenschaftliches Institut für Arbeitssicherheit (ed) BIA-Arbeitsmappe Messung von Gefahrstoffen, 28. Lfg. IV/02. Erich Schmidt Verlag, Bielefeld (Article in German)Google Scholar
- DECOS (Dutch Expert Committee on Occupational Standards) (1998) Endotoxins: health based recommended exposure limit. In: A report of the Health Council of the Netherlands, publication no 1998/03WGD. Health Council of the Netherlands, Rijswijk, pp 1–82Google Scholar
- Health Council of the Netherlands (2010) Endotoxins. Health-based recommended occupational exposure limit. Health Council of the Netherlands, The HagueGoogle Scholar
- Hoffmeyer F, van Kampen V, Taeger D, Deckert A, Rosenkranz N, Kaßen M, Schantora AL, Brüning T, Raulf M, Bünger J (2014) Prevalence of and relationship between rhinoconjunctivitis and lower airway diseases in compost workers with current or former exposure to organic dust. Ann Agric Environ Med 21:705–711CrossRefGoogle Scholar
- Radon K, Garz S, Riess A, Koops F, Monso E, Weber C, Danuser B, Iversen M, Opravil U, Donham K, Hartung J, Pedersen S, Nowak D (2003) Respiratory diseases in European farmers-II. Part of the European farmers’ project. Atemwegs- und Lungenerkrankungen in der Europäischen Landwirtschaft – Teil 2: Ergebnisse der europäischen Landwirtschaftsstudie. Pneumologie (Stuttgart, Germany) 57:510–517CrossRefGoogle Scholar
- Reynolds SJ, Milton DK, Heederik D, Thorne PS, Donham KJ, Croteau EA, Kelly KM, Douwes J, Lewis D, Whitmer M, Connaughton I, Koch S, Malmberg P, Larsson B, Deddens J, Saraf A, Larsson L (2005) Interlaboratory evaluation of endotoxin analyses in agricultural dusts-comparison of LAL assay and mass spectrometry. J Environ Monit 7:1371–1377CrossRefGoogle Scholar
- Rieger MA, Diefenbach H (2007) Biological stress and strain in the field of waste water management – how important is endotoxin? Gefahrstoffe – Reinhaltung der Luft 67:363–366Google Scholar
- Rylander R (1995) Endotoxins in the environment. In: Lewin J, Alving CR, Munford RS, Redl H (eds) Bacterial endotoxins, lipopolysaccharids from genes to therapy. Proceedings of the third conference of the international endotoxin society. Wiley-Liss Inc, New York, pp 79–90Google Scholar
- Sigsgaard T, Thorne PS, Schlünssen V, Bønløkke J, Riddervold IS, Hoppe KA, Andersen NT, Mackenzie NM (2015) The change in nasal inflammatory markers after intranasal challenges with particulate chitin and lipopolysaccharide: a randomized, double-blind, placebo-controlled, crossover study with a positive control. Int Forum Allergy Rhinol 5:716–723CrossRefGoogle Scholar
- Steinberg R (2001) Belastungen und Beanspruchungen von Beschäftigten in Arbeitsbereichen der Abwasserwirtschaft unter besonderer Berücksichtigung der Gefährdung durch biologische Arbeitsstoffe. Gesellschaft für Abwassertechnik e.V. (GFA), Hennef (Article in German)Google Scholar
- Walser SM, Gerstner DG, Brenner B, Bünger J, Eikmann T, Janssen B, Kolb S, Kolk A, Nowak D, Raulf M, Sagunski H, Sedlmaier N, Suchenwirth R, Wiesmüller G, Wollin K, Tesseraux I, Herr CE (2015) Evaluation of exposure-response relationships for health effects of microbial bioaerosols – a systematic review. Int J Hyg Environ Health 218(7):577–589CrossRefGoogle Scholar