title: Levels and predictors of airborne and internal exposure to manganese and iron among welders.
abstract: We investigated airborne and internal exposure to manganese (Mn) and iron (Fe) among welders. Personal sampling of welding fumes was carried out in 241 welders during a shift. Metals were determined by inductively coupled plasma mass spectrometry. Mn in blood (MnB) was analyzed by graphite furnace atom absorption spectrometry. Determinants of exposure levels were estimated with multiple regression models. Respirable Mn was measured with a median of 62 (inter-quartile range (IQR) 8.4-320) μg/m(3) and correlated with Fe (r=0.92, 95% CI 0.90-0.94). Inhalable Mn was measured with similar concentrations (IQR 10-340 μg/m(3)). About 70% of the variance of Mn and Fe could be explained, mainly by the welding process. Ventilation decreased exposure to Fe and Mn significantly. Median concentrations of MnB and serum ferritin (SF) were 10.30 μg/l (IQR 8.33-13.15 μg/l) and 131 μg/l (IQR 76-240 μg/l), respectively. Few welders were presented with low iron stores, and MnB and SF were not correlated (r=0.07, 95% CI -0.05 to 0.20). Regression models revealed a significant association of the parent metal with MnB and SF, but a low fraction of variance was explained by exposure-related factors. Mn is mainly respirable in welding fumes. Airborne Mn and Fe influenced MnB and SF, respectively, in welders. This indicates an effect on the biological regulation of both metals. Mn and Fe were strongly correlated, whereas MnB and SF were not, likely due to higher iron stores among welders.
authors.affiliation: Center of Epidemiology, Institute for Prevention and Occupational Medicine of the German Social Accident Insurance, Institute of the Ruhr-Universität Bochum (IPA), Bürkle-de-la-Camp-Platz, Bochum, Germany. pesch@ipa-dguv.de
authors.forename: Beate
authors.initials: B
authors.lastname: Pesch
authors.forename: Tobias
authors.initials: T
authors.lastname: Weiss
authors.forename: Benjamin
authors.initials: B
authors.lastname: Kendzia
authors.forename: Jana
authors.initials: J
authors.lastname: Henry
authors.forename: Martin
authors.initials: M
authors.lastname: Lehnert
authors.forename: Anne
authors.initials: A
authors.lastname: Lotz
authors.forename: Evelyn
authors.initials: E
authors.lastname: Heinze
authors.forename: Heiko Udo
authors.initials: HU
authors.lastname: Käfferlein
authors.forename: Rainer
authors.initials: R
authors.lastname: Van Gelder
authors.forename: Markus
authors.initials: M
authors.lastname: Berges
authors.forename: Jens-Uwe
authors.initials: JU
authors.lastname: Hahn
authors.forename: Markus
authors.initials: M
authors.lastname: Mattenklott
authors.forename: Ewald
authors.initials: E
authors.lastname: Punkenburg
authors.forename: Andrea
authors.initials: A
authors.lastname: Hartwig
authors.forename: Thomas
authors.initials: T
authors.lastname: Brüning
mesh_terms: D000293:Adolescent; D000328:Adult; D000395:Air Pollutants, Occupational / Q000633:toxicity*; D006801:Humans; D019570:Inhalation Exposure; D007501:Iron / Q000633:toxicity*; D008345:Manganese / Q000633:toxicity*; D008875:Middle Aged; D016273:Occupational Exposure; D014896:Welding
chemical_list: D000395:Air Pollutants, Occupational; D008345:Manganese; D007501:Iron