Abstract: Biomonitoring has been employed since the nineteenth century as a tool for detecting changes in environmental quality. Regarding air quality, biomonitoring applies plant species for which standard assays enable tracking direct and immediate effect of pollutants, as well as the release of toxic compounds, such as metals found in particulate matter (PM), into the ecosystem. This is extremely relevant considering that ecosystem health is linked to human health as according to the One Health Approach. Given the above, this research aims to conduct biomonitoring of air quality by using the standard grass species Lolium multiflorum as a tool for air quality monitoring in the city of Brumadinho. The municipality (39,915 inhabitants) is situated within the Metropolitan Region of Belo Horizonte (2,315,560 inhabitants), the capital of Minas Gerais, Brazil, and the region is largely impacted by mining activities that release high loads of particulate matter into the atmosphere. Bioindicator plants were cultivated for 4 weeks prior to exposure in a natural reserve selected as the reference location away from the influence of both construction and mining as a control. The plants were exposed for 28 days at 3 sampling points (i – City Center, ii – Tejuco neighborhood, surrounded by mining sites, and iii – an indigenous community area near a ferry line used for mining ore transportation), along with the reference point (a natural reserve). At the end of exposure period, the leaves were manually cut and subjected to laboratory analysis to evaluate the presence of metals. Briefly, for each sampling point, triplicates of the plant material were freeze-dried, macerated, and then wet-opened digestion with a nitric acid and hydrogen peroxide solution (1:1) under a graded temperature scheme (60-120 Celsius). Metals present in the extracts were identified and quantified using inductively coupled plasma optical emission spectrometry (ICP-OES). Additionally, fine particulate matter of 2.5 micrometers or less in diameter (PM2.5) were sampled using a medium-volume sampler (ARA Instrument) equipped with quartz filters. PM2.5 samples were carried out for 24 hours in the same locations of plant exposure, twice a week, throughout the exposure period. Then, the aforementioned methodology of metal extraction was carried out through acid digestion followed by analysis in ICP-OES. Based on biomonitoring, it is expected that these plants are proficient indicators of particulate matter pollution especially considering its ability to absorb metals present in PM near mining sites. Furthermore, this is important to highlight that changes in land use and occupation have the potential to impact air quality and this was reflected in exposed plants. A distinct chemical composition of the material collected at the reference point compared to the other sampling points is expected. These analyses will provide additional insights about the effect of metals present in particulate matter and their implications to the health of ecosystems.

Keywords: Bioaccumulation, One Health, Mining, Particulate Matter, Lolium multiflorum.