title: Occupational Exposure to Cobalt and Tungsten in the Swedish Hard Metal Industry: Air Concentrations of Particle Mass, Number, and Surface Area.
abstract: Exposure to cobalt in the hard metal industry entails severe adverse health effects, including lung cancer and hard metal fibrosis. The main aim of this study was to determine exposure air concentration levels of cobalt and tungsten for risk assessment and dose-response analysis in our medical investigations in a Swedish hard metal plant. We also present mass-based, particle surface area, and particle number air concentrations from stationary sampling and investigate the possibility of using these data as proxies for exposure measures in our study. Personal exposure full-shift measurements were performed for inhalable and total dust, cobalt, and tungsten, including personal real-time continuous monitoring of dust. Stationary measurements of inhalable and total dust, PM2.5, and PM10 was also performed and cobalt and tungsten levels were determined, as were air concentration of particle number and particle surface area of fine particles. The personal exposure levels of inhalable dust were consistently low (AM 0.15mg m(-3), range <0.023-3.0mg m(-3)) and below the present Swedish occupational exposure limit (OEL) of 10mg m(-3) The cobalt levels were low as well (AM 0.0030mg m(-3), range 0.000028-0.056mg m(-3)) and only 6% of the samples exceeded the Swedish OEL of 0.02mg m(-3) For continuous personal monitoring of dust exposure, the peaks ranged from 0.001 to 83mg m(-3) by work task. Stationary measurements showed lower average levels both for inhalable and total dust and cobalt. The particle number concentration of fine particles (AM 3000 p·cm(-3)) showed the highest levels at the departments of powder production, pressing and storage, and for the particle surface area concentrations (AM 7.6 µm(2)·cm(-3)) similar results were found. Correlating cobalt mass-based exposure measurements to cobalt stationary mass-based, particle area, and particle number concentrations by rank and department showed significant correlations for all measures except for particle number. Linear regression analysis of the same data showed statistically significant regression coefficients only for the mass-based aerosol measures. Similar results were seen for rank correlation in the stationary rig, and linear regression analysis implied significant correlation for mass-based and particle surface area measures. The mass-based air concentration levels of cobalt and tungsten in the hard metal plant in our study were low compared to Swedish OELs. Particle number and particle surface area concentrations were in the same order of magnitude as for other industrial settings. Regression analysis implied the use of stationary determined mass-based and particle surface area aerosol concentration as proxies for various exposure measures in our study.
authors.affiliation: 1.Department of Occupational and Environmental Medicine, Örebro University, 70185 Örebro, Sweden; 2.School of Health and Medical Sciences, Örebro University, 70185 Örebro, Sweden; maria.klasson@regionorebrolan.se.
authors.forename: Maria
authors.initials: M
authors.lastname: Klasson
authors.affiliation: 1.Department of Occupational and Environmental Medicine, Örebro University, 70185 Örebro, Sweden;
authors.forename: Ing-Liss
authors.initials: IL
authors.lastname: Bryngelsson
authors.affiliation: 1.Department of Occupational and Environmental Medicine, Örebro University, 70185 Örebro, Sweden;
authors.forename: Carin
authors.initials: C
authors.lastname: Pettersson
authors.affiliation: 1.Department of Occupational and Environmental Medicine, Örebro University, 70185 Örebro, Sweden;
authors.forename: Bente
authors.initials: B
authors.lastname: Husby
authors.affiliation: 1.Department of Occupational and Environmental Medicine, Örebro University, 70185 Örebro, Sweden;
authors.forename: Helena
authors.initials: H
authors.lastname: Arvidsson
authors.affiliation: 1.Department of Occupational and Environmental Medicine, Örebro University, 70185 Örebro, Sweden; 3.Department of Science Man-Technology-Environment Research Center (MTM), Örebro University, 70182 Örebro, Sweden.
authors.forename: Håkan
authors.initials: H
authors.lastname: Westberg
mesh_terms: D000395:Air Pollutants, Occupational; D000497:Alloys; D003035:Cobalt / Q000009:adverse effects / Q000032:analysis*; D004391:Dust / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods; D006801:Humans; D007221:Industry; D016273:Occupational Exposure; D052638:Particulate Matter / Q000032:analysis*; D018570:Risk Assessment; D013548:Sweden; D014414:Tungsten / Q000009:adverse effects / Q000032:analysis*
chemical_list: D000395:Air Pollutants, Occupational; D000497:Alloys; D004391:Dust; D052638:Particulate Matter; C080121:hard metal; D003035:Cobalt; D014414:Tungsten
keywords: cobalt exposure in the hard metal industry; occupational exposure; particle mass; particle number; particle surface area; personal exposure measurements; stationary measurements