Environmental Science and Pollution Research, Jan 20, 2021
Particulate matter (PM) deposition on urban green enables the collection of particulate pollution... more Particulate matter (PM) deposition on urban green enables the collection of particulate pollution from a diversity of contexts, and insight into the physico-chemical profiles of PM is key for identifying main polluting sources. This study reports on the morphological and elemental characterization of PM2–10 deposited on ivy leaves from five different environments (forest, rural, roadside, train, industry) in the region of Antwerp, Belgium. Ca. 40,000 leaf-deposited particles were thoroughly investigated by particle-based analysis using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDX) and their physico-chemical characteristics were explored for PM source apportionment purposes. The size distribution of all deposited particles was biased towards small-sized PM, with 32% of the particles smaller than 2.5 μm (PM2.5) and median diameters of 2.80–3.09 μm. The source type influenced both the particles’ size and morphology (aspect ratio and shape), with roadside particles being overall the smallest in size and the most spherical. While forest and rural elemental profiles were associated with natural PM, the industry particles revealed the highest anthropogenic metal input. PM2–10 profiles for roadside and train sites were rather comparable and only distinguishable when evaluating the fine (2–2.5 μm) and coarse (2.5–10 μm) PM fractions separately, which enabled the identification of a larger contribution of combustion-derived particles (small, circular, Fe-enriched) at the roadside compared to the train. Random forest prediction model classified the source type correctly for 61–85% of the leaf-deposited PM. The still modest classification accuracy denotes the influence of regional background PM and demands for additional fingerprinting techniques to facilitate source apportionment. Nonetheless, the obtained results demonstrate the utility of leaf particle-based analysis to fingerprint and pinpoint source-specific PM, particularly when considering both the composition and size of leaf-deposited particles.
To select plant species for particulate matter (PM) removal from urban environments, it is import... more To select plant species for particulate matter (PM) removal from urban environments, it is important to consider the plant species’ ecosystem (dis)services and environmental suitability in addition to their effectiveness in PM removal. In this study, 61 plant species were ranked for PM removal using three separate models: (i) leaf traits, (ii) leaf saturation isothermal remanent magnetization (SIRM), and (iii) ecosystem services and disservices. The plant species’ effectiveness in PM accumulation and the effective leaf traits were identified using leaf SIRM. In each model, plant species were assigned scores and weights for each criterion. The weighted average or the product (Π)-value was calculated for each plant species. The weighted average of each plant species was multiplied by the scores of leaf longevity and leaf area index (LAI) to scale up to a yearly basis and per unit of ground surface area. The preference ranking organization method for enrichment of evaluations (PROMETHE...
Greenhouses, though highly effective agricultural environments, are characterized by reduced sour... more Greenhouses, though highly effective agricultural environments, are characterized by reduced sources of bacterial diversity and means of dispersal compared to more natural settings. As it is known that plant health and productivity are affected by associated bacteria, improving our knowledge on the bacterial communities on greenhouse crops is key to further innovate in horticulture.
Due to ever increasing awareness about the health relevance of Ultrafine particles (UFP) several ... more Due to ever increasing awareness about the health relevance of Ultrafine particles (UFP) several studies have examined particle number concentrations (Rank et al., 2001; Gulliver and Briggs, 2007; Briggs et al., 2008), using a variety of different measurement methods. Exposures to UFP in traffic are generally higher than and poorly correlated with concentrations measured simultaneously at fixed monitoring locations, even if these are located in major streets (Kaur et al., 2007). Hence characterization of UFP cannot rely only on fixed site monitoring. A combined mobile and fixed monitoring have been performed to understand fine scale dynamics of UFP within a grid of 1 Km at Borgerhout, Antwerp, Belgium.
Leaves of sixteen urban plant species were examined for particle density in June and September 20... more Leaves of sixteen urban plant species were examined for particle density in June and September 2016 using scanning electron microscopy (SEM). The particle density was estimated by particle size fraction and leaf sides. The total particle density for coarse and fine fraction on both the abaxial and the adaxial leaf side ranged between 202 to 10,981 particles mm in June and 30 to 1,984 particles mm in September. To determine the repeatability of the SEM methodology for particle density assessment, repeated measurements were performed at long time-intervals in different SEM sessions and on short time-intervals within the same SEM session. The withinsession successive repeated measurements elucidated that features constructing the topography of a leaf surface frequently contributed towards the edge enhancement effect, resulting in exaggerated particle counts. Besides, the mechanical drift and charging effects contributed to the disparity in particle densities. The results from our study...
In this work the potential of moving moss-bags, fixed to bicycles, to intercept particulate matte... more In this work the potential of moving moss-bags, fixed to bicycles, to intercept particulate matter (PM) and linked metal(loid)s was tested for the first time. Seven volunteers carried three moss-bags for fifty days while commuting by bicycle in the urban area of Antwerp, Belgium. Moreover, one bike, equipped with mobile PM samplers, travelled along four routes: urban, industrial, green route and the total path, carrying three moss-bags at each route. The saturation isothermal remanent magnetization (SIRM) signal and chemical composition (assessed by HR-ICP-MS) of the moss samples indicated that the industrial route was the most polluted. Element fluxes (i.e., the ratio between element daily uptake and the specific leaf area) could discriminate among land uses; particularly, they were significantly higher in the industrial route for Ag, As, Cd and Pb; significantly lowest in the green route for As and Pb; and comparable for all accumulated elements along most urban routes. A comparis...
Soil magnetic measurements are used increasingly to estimate the impact of airborne, combustion-r... more Soil magnetic measurements are used increasingly to estimate the impact of airborne, combustion-related particulate matter (PM) pollution in dense measurement grids. Although many studies have proven the potential of topsoil magnetic measurements in environmental monitoring, their application is not straightforward when factors such as parent material or land use have to be accounted for. Often, the influence of land use on the soil magnetic signal is circumvented by targeting forest soils, where deposited magnetic particles are best preserved in the topsoil. However, when large forests are absent, e.g. in densely populated areas or environments with more heterogeneous land use, this approach often impedes reliable and comprehensive spatial sampling. We evaluated if topsoil magnetic pollution mapping across different land use classes, against a homogeneous geological environment of sandy soils, could help increase the spatial reliability of results in regional scale surveys. Although detailed magnetic property analysis and evaluation of trace metal concentrations in soils on arable land, forest and pasture showed the impact of atmospheric pollution, topsoil susceptibility measurements did not allow delineating the magnetic footprint of PM pollution. Land use strongly influenced the distribution of magnetic particles through soil, and the evaluation of anomalous magnetic topsoil enhancement required the integration of downhole susceptibility soundings. We conclude that topsoil susceptibility mapping remains a useful tool to evaluate PM pollution impact, yet its application potential across land use classes is limited.
Environmental Science and Pollution Research, Jan 20, 2021
Particulate matter (PM) deposition on urban green enables the collection of particulate pollution... more Particulate matter (PM) deposition on urban green enables the collection of particulate pollution from a diversity of contexts, and insight into the physico-chemical profiles of PM is key for identifying main polluting sources. This study reports on the morphological and elemental characterization of PM2–10 deposited on ivy leaves from five different environments (forest, rural, roadside, train, industry) in the region of Antwerp, Belgium. Ca. 40,000 leaf-deposited particles were thoroughly investigated by particle-based analysis using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDX) and their physico-chemical characteristics were explored for PM source apportionment purposes. The size distribution of all deposited particles was biased towards small-sized PM, with 32% of the particles smaller than 2.5 μm (PM2.5) and median diameters of 2.80–3.09 μm. The source type influenced both the particles’ size and morphology (aspect ratio and shape), with roadside particles being overall the smallest in size and the most spherical. While forest and rural elemental profiles were associated with natural PM, the industry particles revealed the highest anthropogenic metal input. PM2–10 profiles for roadside and train sites were rather comparable and only distinguishable when evaluating the fine (2–2.5 μm) and coarse (2.5–10 μm) PM fractions separately, which enabled the identification of a larger contribution of combustion-derived particles (small, circular, Fe-enriched) at the roadside compared to the train. Random forest prediction model classified the source type correctly for 61–85% of the leaf-deposited PM. The still modest classification accuracy denotes the influence of regional background PM and demands for additional fingerprinting techniques to facilitate source apportionment. Nonetheless, the obtained results demonstrate the utility of leaf particle-based analysis to fingerprint and pinpoint source-specific PM, particularly when considering both the composition and size of leaf-deposited particles.
To select plant species for particulate matter (PM) removal from urban environments, it is import... more To select plant species for particulate matter (PM) removal from urban environments, it is important to consider the plant species’ ecosystem (dis)services and environmental suitability in addition to their effectiveness in PM removal. In this study, 61 plant species were ranked for PM removal using three separate models: (i) leaf traits, (ii) leaf saturation isothermal remanent magnetization (SIRM), and (iii) ecosystem services and disservices. The plant species’ effectiveness in PM accumulation and the effective leaf traits were identified using leaf SIRM. In each model, plant species were assigned scores and weights for each criterion. The weighted average or the product (Π)-value was calculated for each plant species. The weighted average of each plant species was multiplied by the scores of leaf longevity and leaf area index (LAI) to scale up to a yearly basis and per unit of ground surface area. The preference ranking organization method for enrichment of evaluations (PROMETHE...
Greenhouses, though highly effective agricultural environments, are characterized by reduced sour... more Greenhouses, though highly effective agricultural environments, are characterized by reduced sources of bacterial diversity and means of dispersal compared to more natural settings. As it is known that plant health and productivity are affected by associated bacteria, improving our knowledge on the bacterial communities on greenhouse crops is key to further innovate in horticulture.
Due to ever increasing awareness about the health relevance of Ultrafine particles (UFP) several ... more Due to ever increasing awareness about the health relevance of Ultrafine particles (UFP) several studies have examined particle number concentrations (Rank et al., 2001; Gulliver and Briggs, 2007; Briggs et al., 2008), using a variety of different measurement methods. Exposures to UFP in traffic are generally higher than and poorly correlated with concentrations measured simultaneously at fixed monitoring locations, even if these are located in major streets (Kaur et al., 2007). Hence characterization of UFP cannot rely only on fixed site monitoring. A combined mobile and fixed monitoring have been performed to understand fine scale dynamics of UFP within a grid of 1 Km at Borgerhout, Antwerp, Belgium.
Leaves of sixteen urban plant species were examined for particle density in June and September 20... more Leaves of sixteen urban plant species were examined for particle density in June and September 2016 using scanning electron microscopy (SEM). The particle density was estimated by particle size fraction and leaf sides. The total particle density for coarse and fine fraction on both the abaxial and the adaxial leaf side ranged between 202 to 10,981 particles mm in June and 30 to 1,984 particles mm in September. To determine the repeatability of the SEM methodology for particle density assessment, repeated measurements were performed at long time-intervals in different SEM sessions and on short time-intervals within the same SEM session. The withinsession successive repeated measurements elucidated that features constructing the topography of a leaf surface frequently contributed towards the edge enhancement effect, resulting in exaggerated particle counts. Besides, the mechanical drift and charging effects contributed to the disparity in particle densities. The results from our study...
In this work the potential of moving moss-bags, fixed to bicycles, to intercept particulate matte... more In this work the potential of moving moss-bags, fixed to bicycles, to intercept particulate matter (PM) and linked metal(loid)s was tested for the first time. Seven volunteers carried three moss-bags for fifty days while commuting by bicycle in the urban area of Antwerp, Belgium. Moreover, one bike, equipped with mobile PM samplers, travelled along four routes: urban, industrial, green route and the total path, carrying three moss-bags at each route. The saturation isothermal remanent magnetization (SIRM) signal and chemical composition (assessed by HR-ICP-MS) of the moss samples indicated that the industrial route was the most polluted. Element fluxes (i.e., the ratio between element daily uptake and the specific leaf area) could discriminate among land uses; particularly, they were significantly higher in the industrial route for Ag, As, Cd and Pb; significantly lowest in the green route for As and Pb; and comparable for all accumulated elements along most urban routes. A comparis...
Soil magnetic measurements are used increasingly to estimate the impact of airborne, combustion-r... more Soil magnetic measurements are used increasingly to estimate the impact of airborne, combustion-related particulate matter (PM) pollution in dense measurement grids. Although many studies have proven the potential of topsoil magnetic measurements in environmental monitoring, their application is not straightforward when factors such as parent material or land use have to be accounted for. Often, the influence of land use on the soil magnetic signal is circumvented by targeting forest soils, where deposited magnetic particles are best preserved in the topsoil. However, when large forests are absent, e.g. in densely populated areas or environments with more heterogeneous land use, this approach often impedes reliable and comprehensive spatial sampling. We evaluated if topsoil magnetic pollution mapping across different land use classes, against a homogeneous geological environment of sandy soils, could help increase the spatial reliability of results in regional scale surveys. Although detailed magnetic property analysis and evaluation of trace metal concentrations in soils on arable land, forest and pasture showed the impact of atmospheric pollution, topsoil susceptibility measurements did not allow delineating the magnetic footprint of PM pollution. Land use strongly influenced the distribution of magnetic particles through soil, and the evaluation of anomalous magnetic topsoil enhancement required the integration of downhole susceptibility soundings. We conclude that topsoil susceptibility mapping remains a useful tool to evaluate PM pollution impact, yet its application potential across land use classes is limited.
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Papers by Roeland Samson