Robinia pseudoacacia L. (Black Locust) Leaflets as Biomonitors of Airborne Microplastics.

Here we investigate the suitability of Robinia pseudoacacia L. (black locust) leaflets as a novel biomonitor of airborne microplastics (MPs) including tyre wear particles (TWPs). Leaflets were collected from rural roadside locations (ROs, n = 5) and urban parks (UPs, n = 5) in Siena, Italy. MPs were removed by washing, identified by stereomicroscope, and analysed for polymer type by Fourier transform infrared spectroscopy. Daily MP deposition was estimated from leaf area. The mass magnetic susceptibility and the bioaccumulation of traffic-related potentially toxic elements (PTEs) were also analysed. The total number of MPs at ROs was significantly higher at 2962, dominated by TWPs, compared with 193 in UPs, where TWPs were not found. In contrast, total microfibres were significantly higher in UPs compared with ROs (185 vs. 86). Daily MP deposition was estimated to range from 4.2 to 5.1 MPs/m2/d across UPs and 29.9-457.6 MPs/m2/d across ROs. The polymer types at ROs were dominated by rubber (80%) from TWPs, followed by 15% polyamide (PA) and 5% polysulfone (PES), while in UPs the proportion of PES (44%) was higher than PA (22%) and polyacrylonitrile (11%). The mean mass magnetic susceptibility, a proxy of the bioaccumulation of traffic-related metallic particles, was higher at ROs (0.62 ± 0.01 10-8 m3/kg) than at UPs (-0.50 ± 0.03 10-8 m3/kg). The content of PTEs was similar across sites, except for significantly higher concentrations of Sb, a tracer of vehicle brake wear, at ROs (0.308 ± 0.008 µg/g) compared with UPs (0.054 ± 0.006 µg/g). Our results suggest that the waxy leaflets and easy determination of surface area make Robinia an effective biomonitor for airborne MPs including TWPs.

Atmospheric Concentration of CO2 and PM2.5 at Salina, Stromboli, and Vulcano Islands (Italy): How Anthropogenic Sources, Ordinary Volcanic Activity and Unrests Affect Air Quality.

Geogenic and anthropogenic sources of atmospheric particulate and CO2 can lead to threats to human health in volcanic areas. Although the volcanic CO2 hazard is a topic frequently debated in the related scientific literature, space and time distribution of PM2.5 are poorly known. The results of combined CO2/PM2.5 surveys, carried out at Salina, Stromboli, and Vulcano islands (Aeolian archipelago, Italy) in the years 2020-2021, and integrated with investigations on bioaccumulation of metallic particulate matter by the mean of data on the magnetic properties of oleander leaves, are presented in this work. The retrieved results indicate that no significant anthropogenic sources for both CO2 and PM2.5 are active in these islands, at the net of a minor contribution due to vehicular traffic. Conversely, increments in volcanic activity, as the unrest experienced by Vulcano island since the second half of 2021, pose serious threats to human health, due to the near-ground accumulation of CO2, and the presence of suspended micro-droplets of condensed hydrothermal vapor, fostering the diffusion of atmophile viruses, such as the COVID-19. Gas hazard conditions can be generated, not only by volcanic vents or fumarolic fields, but also by unconventional sources, such as the outgassing from shallow hydrothermal aquifers through drilled or hand-carved wells.

Assessing the impact of vehicular particulate matter on cultural heritage by magnetic biomonitoring at Villa Farnesina in Rome, Italy.

Magnetic biomonitoring methodologies were applied at Villa Farnesina, Rome, a masterpiece of the Italian Renaissance, with loggias frescoed by renowned artists such as Raffaello Sanzio. Plant leaves were sampled in September and December 2020 and lichen transplants were exposed from October 2020 to early January 2021 at increasing distances from the main trafficked road, Lungotevere Farnesina, introducing an outdoor vs. indoor mixed sampling design aimed at assessing the impact of vehicular particulate matter (PM) on the Villa Loggias. The magnetic properties of leaves and lichens - inferred from magnetic susceptibility values, hysteresis loops and first order reversal curves - showed that the bioaccumulation of magnetite-like particles, associated with trace metals such as Cu, Ba and Sb, decreased exponentially with the distance from the road, and was mainly linked to metallic emission from vehicle brake abrasion. For the frescoed Halls, ca. 30 m from the road, the exposure to traffic-related emissions was very limited or negligible. Tree and shrub leaves of the Lungotevere and of the Villa's Gardens intercepted much traffic-derived PM, thus being able to protect the indoor cultural heritage and providing an essential conservation service. It is concluded that the joint use of magnetic and chemical analyses can profitably be used for evaluating the impact of particulate pollution on cultural heritage within complex metropolitan contexts as a preventive conservation measure.

Superparamagnetic Iron Oxide Nanoparticle Nanodevices Based on Fe3O4 Coated by Megluminic Ligands for the Adsorption of Metal Anions from Water.

The uptake ability toward arsenic(V), chromium(VI), and boron(III) ions of ad hoc functionalized magnetic nanostructured devices has been investigated. To this purpose, ligands based on meglumine have been synthesized and used to coat magnetite nanoparticles (Fe3O4) obtained by the co-precipitation methodology. The as-prepared hybrid material was characterized by infrared spectroscopy (IR), X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy combined with energy-dispersive X-ray analysis. Moreover, its magnetic hysteresis properties were measured to evaluate its magnetic properties, and the adsorption kinetics and isothermal models were applied to discern between the different adsorption phenomena. Specifically, the better fitting was observed by the Langmuir isotherm model for all metal ions tested, highlighting a higher uptake in arsenic (28.2 mg/g), chromium (12.3 mg/g), and boron (23.7 mg/g) sorption values if compared with other magnetic nanostructured materials. After adsorption, an external magnetic stimulus can be used to efficiently remove nanomaterials from the water. Finally the nanomaterial can be reused up to five cycles and regenerated for another three cycles.

The effect of Covid-19 lockdown on airborne particulate matter in Rome, Italy: A magnetic point of view.

Between 9 March and 18 May 2020, strict lockdown measures were adopted in Italy for containing the COVID-19 pandemic: in Rome, despite vehicular traffic on average was more than halved, it was not observed a evident decrease of the airborne particulate matter (PM) concentrations, as assessed by air quality data. In this study, daily PM10 filters were collected from selected automated stations operated in Rome by the regional network of air quality monitoring: their magnetic properties - including magnetic susceptibility, hysteresis parameters and FORC (first order reversal curves) diagrams - were compared during and after the lockdown, for outlining the impact of the COVID-19 measures on airborne particulate matter. In urban traffic sites, the PM10 concentrations did not significantly change after the end of the lockdown, when vehicular traffic promptly returned to its usual levels; conversely, the average volume and mass magnetic susceptibilities approximately doubled, and the linear correlation between volume magnetic susceptibility and PM10 concentration became significant, pointing out the link between PM10 concentrations and the increasing levels of traffic-related magnetic emissions. Magnetite-like minerals, attributed to non-exhaust brakes emissions, dominated the magnetic fraction of PM10 near urban traffic sites, with natural magnetic components emerging in background sites and during exogenous dusts atmospheric events. Magnetic susceptibility constituted a fast and sensitive proxy of vehicular particulate emissions: the magnetic properties can play a relevant role in the source apportionment of PM10, especially when unsignificant variations in its concentration levels may mask important changes in the traffic-related magnetic fraction. As a further hint, increasing attention should be drawn to the reduction of brake wear emissions, that are overcoming by far fuel exhausts as the main particulate pollutant in traffic contexts.

Combined magnetic, chemical and morphoscopic analyses on lichens from a complex anthropic context in Rome, Italy.

Native and transplanted lichens were analyzed as bioaccumulators of airborne particulate matter (PM) in an eastern district of Rome, Italy, where frequent fraudulent fires are set to recover metals, mostly copper, from waste electrical and electronic equipment (WEEE). The presence of native lichens was scarce, due to the drought of spring-summer 2017, thus, sampling was extended to a neighboring area for toughening the dataset to a similar context. The magnetic analyses revealed intense properties connected to the anthropic complexity of the zone, where industrial, traffic and arson-related dusts are emitted and bio-accumulated. Magnetic and chemical analyses were compared, leading to significant linear correlations between the concentration dependent magnetic parameters (susceptibility, saturation magnetization and saturation remanence) and the concentration of heavy metals, among which copper, chrome, lead and zinc. Moreover, selected magnetic particles were chemically and morphologically characterized by Scanning Electron Microscope and Energy Dispersion System microanalyses. Magnetic particles resulted incorporated into the lichens' tissues and their composition, morphology and grain size strongly supported their anthropogenic, mostly combustion-related, origin. Even if, given the complexity of the area, it was not feasible to fully discriminate the multiple anthropogenic sources, magnetic biomonitoring of lichens, especially when combined with microtextural and compositional analyses, confirmed to be an excellent methodology for a rapid characterization of environmental pollution.

Biomagnetic monitoring and element content of lichen transplants in a mixed land use area of NE Italy.

The aim of this study was to verify whether it is possible to discriminate between the different pollution sources present in a mixed land use area of NE Italy on the basis of the magnetic properties and the element content of lichen transplants. Thalli of Pseudevernia furfuracea were collected in a pristine area of the South-Eastern Alps and exposed for 2months in 40 sites located at the knots of a 700m step grid covering ca. 40km2 of a mosaic of agricultural, forested, industrial and urban areas. In this way, the samples could be analyzed after a defined period of time, and compared to pre-exposure conditions. The post-exposure element content and the magnetic data substantially agreed, revealing a rather modest anthropogenic impact on the territory, mostly limited to an industrial park. Since the magnetic mineralogy was homogeneous throughout the entire set of samples, with magnetite-like minerals as the main magnetic carriers, it was not possible to discriminate between PM originating from the different pollution sources. The contribution given by the industrial park could be confirmed by the multivariate analysis of the element data set. Conversely, it was possible to assess the low environmental impact of the largest local industry, a cement plant, located outside the industrial park. Notwithstanding the relatively short time of the survey, P. furfuracea was proven to be an effective accumulator for biomagnetic monitoring studies, its magnetic properties being excellent proxies for heavy metal pollution even when the anthropogenic impact on the territory is low.

Magnetic properties and element concentrations in lichens exposed to airborne pollutants released during cement production.

The content of selected elements (Al, As, Ca, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, S, Ti, V and Zn) was measured in samples of the lichen Evernia prunastri exposed for 30, 90 and 180 days around a cement mill, limestone and basalt quarries and urban and agricultural areas in SW Slovakia. Lichens transplanted around the investigated quarries and the cement mill rapidly (30 days) reflected the deposition of dust-associated elements, namely Ca (at the cement mill and the limestone quarry) and Fe, Ti and V (around the cement mill and the basalt quarry), and their content remained significantly higher throughout the whole period (30-180 days) with respect to the surrounding environment. Airborne pollutants (such as S) progressively increased in the study area from 30 to 180 days. The magnetic properties of lichen transplants exposed for 180 days have been characterized and compared with those of native lichens (Xanthoria parietina) and neighbouring bark, soil and rock samples, in order to test the suitability of native and transplanted samples as air pollution magnetic biomonitors. The magnetic mineralogy was homogeneous in all samples, with the exception of the samples from the basalt quarry. The transplants showed excellent correlations between the saturation remanent magnetization (Mrs) and the content of Fe. Native samples had a similar magnetic signature, but the values of the concentration-dependent magnetic parameters were up to two orders of magnitude higher, reflecting higher concentrations of magnetic particles. The concentrations of As, Ca and Cr in lichens correlated with Mrs values after neglecting the samples from the basalt quarry, which showed distinct magnetic properties, suggesting the cement mill as a likely source. Conversely, Ti and Mn were mostly (but not exclusively) associated with dust from the basalt quarry. It is suggested that the natural geological characteristics of the substrate may strongly affect the magnetic properties of lichen thalli. Taking this into account, the results of this study point out the suitability of lichens as air pollution magnetic biomonitors.