Rock magnetic and micro-morphological analysis on snow deposits: recognition of anthropogenic origin of particulate matter in urban and wilderness areas (central Italy)

Laura Alfonsi,Patrizia Macrì,Manuela Nazzari

doi:10.4401/ag-8515

Laura Alfonsi, Patrizia Macrì + Show 1 more

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https://doi.org/10.4401/ag-8515

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Abstract

Low field magnetic susceptibility and other rock magnetic analyses are applied to inspect the magnetic nature of solid residuals in snow samples collected in downtown Rome and in two Natural Parks in central Italy. Field emission scanning electron microscope and energy dispersive spectroscopy (FESEM-EDS) analyses are utilized to reveal the nature of Fe-rich particles and discriminate their anthropogenic origin. The results indicate that magnetite (Fe3O4) is the main magnetic carrier in almost all samples and that the variations in concentration are directly associated with local sources of particulate matter (PM) from anthropogenic pollution related to automotive circulation in both environments. Magnetic minerals of other provenance are found as accessories. The snow deposits revealed to be an efficient neutral tool for fine particle collections, also in environments characterized by different concentration and source of pollutants.

Highlights

In the recent past a series of studies concerning snow analyses demonstrated the capacity of snowflakes to capture pollutants from the atmosphere in region characterized by cold climatic conditions [e.g. Engelhard et al, 2007; Nazarenko et al, 2017]
The results indicate that magnetite (Fe3O4) is the main magnetic carrier in almost all samples and that the variations in concentration are directly associated with local sources of particulate matter (PM) from anthropogenic pollution related to automotive circulation in both environments
The mass specific magnetic susceptibility distribution indicates an evident relation with the closeness of great urban area and, as expected, the maximum values are observed at sites close to high traffic roads and urban clusters

Summary

Introduction

In the recent past a series of studies concerning snow analyses demonstrated the capacity of snowflakes to capture pollutants from the atmosphere in region characterized by cold climatic conditions [e.g. Engelhard et al, 2007; Nazarenko et al, 2017]. The snow sampling was employed as a primary source of information for environmental data in areas where no dedicated monitoring systems were available, especially in those regions where the snow characterizes the majority of the atmospheric precipitation [Gabrielli et al, 2008; Kuoppamaki et al, 2014]. In both wilderness unexploited areas and urban sites, others tools but snow are commonly employed in pollution assessment studies. Lichens demonstrated to be an efficient bioindicators of air quality in different environment [Conti and Cecchetti, 2001; Abas, 2021]

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