Development of a Standardised Method for Measuring Manganese Exposure

The aim of this project is to propose a standard or reference method for sampling airborne Manganese (Mn), so Mn exposure levels can be compared between manganese and manganese compound manufacturing from different countries. A systematic literature review was undertaken to identify key references reporting comparisons between aerosol samplers and analytical methods used to assess Mnair exposures and for the more general measurement of dust in workplaces. In addition, information on current samplers used by the industry was collected througha questionnaire which was distributed to the International Manganese Institute (IMnI) members. The results of the literature review, together with the information collected throughthe questionnaire survey were presented and discussed with IMnI representatives. The discussion lead to the selection of three candidate methods: the IOM head for the inhalable fraction, the Higgins Dewell (HD) cyclone for the respirable fraction and the Conical Inhalable sampler (CIS) for the simultaneous collection of both fractions. The selection was based on following requirements: the samplers should follow the CEN/ISO/ACGIH criteria for collection of inhalable and respirable airborne particles and the sampling medium should not impede the chemical analyses of Mn as well asavailability and usability. The performance of these three candidate methods was compared in four sampling campaigns at four separate Mn production facilities. A standardised sampling surveyprotocol was developed and followed to ensure samples were collected in a similar way. Parallel personal (CIS vs. IOM or CIS vs. cyclone) and static samples (CIS vs. IOM vs. cyclone) were collected at each facility. The sampling strategy aimed tosamples at a spectrum of potential Mn exposures, covering a range of different industrial processes.A total of 47 paired personal samples (24 CIS-Inhalable: IOM and 23 CIS-Respirable: cyclone) and 65 paired static samples (30 CIS-Inhalable: IOM and 35 CISRespirable: cyclone) were collected. Samples collected with the CIS sampler overestimated the concentrations relative to samples collected with the IOM head (inhalable) and HD cyclone (respirable). The arithmetic mean of the dust ratios CIS-I: IOM was 8.07 and 1.85 for personal and static samples, respectively, whereas theratio between the CIS-R and the cyclone was 1.91 and 1.76 for the personal and static measurements, respectively. For Mn, the AM ratios were 3.39 and 2.10 for personal and static CIS-I: IOM, and 9.53 and 2.64 for personal and static CIS-R: cyclone. “”