Personal inhalation exposure to manganese and other trace metals in an environmentally exposed population: bioaccessibility in size-segregated particulate matter samples

Exposure to environmental airborne manganese (Mn) can lead to neurotoxic disorders and cognitive deficits. The degree of exposure can be assessed by personal sampling of particulate matter (PM) or through biomarkers of exposure. The aim of this work was to characterise the personal exposure to airborne Mn and other trace metals by measuring their bioaccessibility in PM filters taken from personal samplers in an environmentally exposed adult population living in the vicinity of a ferromanganese alloy plant in Santander Bay (northern Spain). Concentrations of bioaccessible and non-bioaccessible Mn and other metals associated with coarse (PM10-2.5) and fine (PM2.5) modes were quantified from 24 h personal samplers in 130 participants divided into two groups according to their Mn exposure: highly (n = 65) and moderately (n = 65) exposed. Gastric fluid and artificial lysosomal fluid (ALF) were used in the bioaccessibility tests as surrogate agents for the body fluids that can come into contact with coarse and fine particles, respectively. The mean air Mn levels in PM10-2.5 and PM2.5 were 127.2 and 126.2 ng/m3, respectively, in the highly exposed group, and 18.6 and 31.7 ng/m3 in the moderately exposed group. The bioaccessibility (%) of Mn in gastric fluid and ALF was also found to be greater in the highly exposed group. The results indicate that people living near Mn alloy plants have an increased potential health risk for Mn exposure due to higher total air Mn concentrations and bioaccessibility.

This work was funded by the Spanish Ministry of Science, Innovation and Universities through Project CTM 2017-82636-R. Bohdana Markiv also thanks the same Ministry for her PhD grant, PRE 2018-085152.