Magnetic biomonitoring of airborne particles using lichen transplants over controlled exposure periods

CHAPARRO, MARCOS A. E.; MARIÉ, DÉBORA C.; LAVAT, ARACELI; SINITO, ANA M.

SN Applied Sciences

Spinger Nature

Año: 2019 vol. 2 p. 1 - 12

2523-3963

Lichens areable to retain airborne pollution-derived particles in their thalli for a longtime, and therefore, their use in assessing atmospheric pollution may besuitable and beneficial. In this study, we transplanted species of Parmotrema pilosum in bags andexposed them to atmospheric pollutants at different sites over the course of 1year. The exposed lichen retained anthropogenic ferrimagnetic Fe oxides thatwere identified and characterized by environmental magnetism methods, X-raydiffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), andscanning electron microscopy (SEM). The ubiquitous magnetite, released bymetallurgical factories and vehicular sources, had small grain sizes (< 0.1?1μm) falling inthe range of harmful particulate matter PM2.5 and PM1.0.According tothe anhysteretic ratios (χARM/χ, ARM/SIRM), magnetic grain size tends to increase (ratiosdecrease) over time. Concentration-dependent magnetic parameters evidenced thecumulative presence of anthropogenic magnetite-like particles which reachedhigh values during the study period, increasing from an initial mass-specificmagnetic susceptibility χ value (mean ±S.D.) of 24.1 ± 5.0 × 10−8 m3 kg−1 to higher values up to 51.2 ± 23.0 × 10−8m3 kg−1. Joint analysis of meteorological data and magneticsusceptibility indicated a magnetic enhancement (χ/χinitial) duringthe austral winter season when mean temperatures were lower; moreover, relativedecreases in χ values afterrainy periods are observed. This simple and low-cost methodology allowed us tostudy, in controlled exposure periods of 1?11 months, the ability oftransplanted lichens to retain fine and ultrafine airborne particles that mayhave impacts on human health.