Magnetic enhancement of urban roadside soils as a proxy of degree of pollution by traffic-related activities

Abstract

Detailed magnetic and geochemical measurements were performed on urban roadside soils collected from Lishui city, China, to establish a possible link between the enhanced concentration of traffic-related magnetic particles and heavy metals. Relatively higher magnetic susceptibility (mean: 124.1 9 10 -8 m 3 kg -1 ) and concentrations of metals (Cd, Cu, Pb and Zn) were observed for roadside soils. Concentration-dependent magnetic parameters (v and SIRM) are highly significantly positively correlated to the concentration of metals (Ca, Cr, Ni, Cu, Zn, Cd, Pb, Fe, and V), but not significantly correlated with As, Mn, Co, Mg, and K. The principal component analysis showed that v and SIRM significantly correspond to elements Ca, Cd, Cu, Pb, and Zn. The v and SIRM also have significant linear correlation with integrated pollution index, indicating that v and SIRM can be used as effective proxy indicators for the pollution of heavy metals. Magnetite in the pseudo-single-domain/multidomain (PSD/MD) grain size was identified as the dominant magnetic carrier by temperature-dependent measurements of saturation magnetization (Ms-T curve), XRD and hysteresis loops. Field emission scanning electron microscopy and energy dispersive X-ray spectroscopy (EDS) analysis of the magnetic particles revealed the presence of large traffic-related angular-subangular, blocky, and spherical iron oxide particles. These iron oxide particles are typical for particles produced by traffic-related anthropogenic activities. It is concluded that vehicle emissions may be the major source of elevated heavy metals and magnetic particles in roadside soils. The results proved the applicability of magnetic method in detecting roadside pollution derived from vehicle emissions.

Effects of Anthropogenic Particles on the Chemical and Geophysical Properties of Urban Soils, Detroit, Michigan

“…Previous studies had shown that EC and MS surveying can provide a much more effective approach for mapping soils in agricultural, archaeological and other settings (Moffat et al, 2010;Doolittle et al, 2002Doolittle et al, , 2013Nearing et al, 2013;Kapper et al, 2014). It was also well established that anthropogenic soils have elevated levels of MS (Strzyszcz et al, 2006) due in part to anthropogenic microparticles (Lu et al, 2011). Anthropogenic microparticles have a significant impact on geophysical signals due to their greater surface area.…”

“…Magnetite or maghemite bearing artifacts greatly contribute to elevated MS of anthropogenic soil. Microparticles, such as ferruginous microspheres, are also known to contribute to the elevated MS signatures of anthropogenic soils (Lu et al, 2011;Yang et al, 2012;El-Baghdadi et al, 2012).…”

Traffic-Related Pollutants in Roadside Soils of Different Countries in Europe and Asia

“…The Gliwice samples had the lowest χ values (31×10 −8 m 3 kg −1 ) ( Table 1). Investigations of roadside soils conducted in different countries (e.g., Korea, Finland, Argentina, China) revealed similar or lower χ values (Kim et al 2009;Bućko et al 2010;Chaparro et al 2010;Lu et al 2011).…”

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“…NON-MAGNETIC MEASUREMENTS / MAGNETIC MONITORING first extracting heavy metals using diethylenetriamine penta-acetate, and subsequently measurements with a spectrometer of atomic absorption. Scanning electron microscope analyses help identify associations between magnetic minerals such as magnetite and heavy metals (Aguilar Reyes et al, 2013) or the overall size distribution and morphology of particles (Urbat et al, 2004;Jordanova et al, 2008;Lu et al, 2011;Chaparro et al, 2013;Castanheiro et al, 2016;Castañeda Miranda et al, 2016;Bourliva et al, 2017). In the case of soils, various measurements can be performed in order to characterize the physico-chemical properties of soils.…”

“…Georgeaud et al (1997) reported that magnetite is a possible carrier of heavy metals such as Pb, Cd, Cr, or Ni. Particles finer in size than 10 µm-called PM 10 -have a high specific surface, which makes these particles efficient carriers of pollutants such as heavy metals and polycyclic aromatic hydrocarbons (PAH) (Hoffmann et al, 1999;Lu et al, 2011). Laboratory studies of iron oxides in redbeds revealed that these particles are highly adsorbent of heavy metals (Rose and Bianchi-Mosquera, 1993).…”