Biomarkers for occupational manganese exposure

Figures & data

Figure 1. An expanded risk characterization paradigm illustrating the role of biomarkers of exposure, effect, and susceptibility (adapted from McClellan (2020)).

Table 1. Summary of evidence from occupational exposure studies on Mn in whole blood as a useful biomarker of airborne Mn exposure.

Occupational settings/type of Mn compounds	Summary of evidence^a
Mn ore mines and Mn ore milling facilities (Insoluble MnO2, dust)	There is limited and inconsistent evidence showing the biomarker can distinguish Mn-exposed and unexposed workers, including dose-related associations with external Mn levels and neurological impairment.
Dry-cell batteries production plants (insoluble MnO2, dust)	There is some evidence showing the biomarker that can distinguish exposed from unexposed workers, though evidence is limited for dose-related associations with external Mn levels and neurological impairment.
Mn oxides and Mn soluble salts production plants (Insoluble Mn oxides and soluble Mn salts, dust)	There is modest evidence in support of the biomarker distinguishing exposed from unexposed workers. Evidence supporting the dose-related association with external exposure is more limited. There is some evidence of a dose-related association with neurological impairment.
Fe-Mn/Si-Mn alloy production plants (MnO2, dust, Mn-containing fume)	There is modest but inconsistent evidence supporting an exposure biomarker that can distinguish exposed and unexposed workers, although evidence supporting dose-related associations with external and Mn concentrations or neurofunctional impairments is more limited and inconsistent.
Welding industry (Mn-containing fume of Mn oxides in a mixture with other occupational hazardous compounds)	There is modest but inconsistent evidence supporting an exposure biomarker that can distinguish exposed and unexposed welders, although evidence supporting dose-related associations with external concentrations is more limited and inconsistent. There is also some evidence of a dose-related association with neurological impairment.

^a Summary of evidence for Mn in whole blood (Mn-B) as a reliable exposure biomarker, based on several characteristics: distinguish between Mn exposed and non-exposed workers; display a dose-related association between Mn concentrations in external and internal media; and display a dose-response association with Mn neurotoxicity (criteria recommended by Hoet and Roels, 2015).

Figure 2. Study flow diagram of records identified and screened [Adapted from Moher et al. (2009)].

McClellan RO. 2020. Health effects of nuclear weapons and releases of radioactive materials. In Gupta RC, editor. Handbook of toxicology of chemical warfare agents. Amsterdam, the Netherlands: Elsevier Publishing; p. 707–743.

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Hoet P, Roels HA. 2015. Chapter 14, Significance and usefulness of biomarkers of exposure to manganese. In Costa LG, Aschner M, editors. Manganese in health and disease. London: The Royal Society of Chemistry; p. 355–401.

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Moher D, Liberati A, Tetzlaff J, Altman DG, PRISMA Group. 2009. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med. 6(7):e1000097.

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