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

• Published in: Environmental earth sciences Vol. 64; no. 2; pp. 359 - 371
• Main Authors: Lu, S. G., Wang, H. Y., Guo, J. L.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.09.2011; Springer; Springer Nature B.V
• Subjects: Air pollution; Anthropogenic factors; Biogeosciences; Cadmium; Copper; Earth and Environmental Science; Earth Sciences; Earth, ocean, space; Emissions; Engineering and environment geology. Geothermics; Environmental Science and Engineering; Exact sciences and technology; Geochemistry; Geology; Geophysics: general, magnetic, electric and thermic methods and properties; Heavy metals; Hydrology/Water Resources; Internal geophysics; Iron oxides; Lead; Metal concentrations; Original Article; Particulates; Pollution index; Pollution, environment geology; Principal components analysis; Roads & highways; roadsides; Soil; Soil contamination; Terrestrial Pollution; Urban areas; Vehicle emissions; X-ray spectroscopy; Zinc; Zhejiang China; Far East; Asia; China; China, People's Rep; Magnetite; Heavy metals; Soil contamination; Magnetic susceptibility; Vehicle emission; oxides; urban environment; heavy metals; X-ray diffraction; SEM data; metals; pseudo-single domains; X-ray spectroscopy; pollution; principal components analysis; hysteresis; particles; soils; multidomains; scanning electron microscopy; magnetite; iron oxides; saturation magnetization; roads; concentration; urban areas; contamination; spinel; grain size; magnetic methods; magnetic susceptibility
• ISSN: 1866-6280; 1866-6299
• DOI: 10.1007/s12665-010-0859-x

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 × 10 −8  m 3  kg −1 ) and concentrations of metals (Cd, Cu, Pb and Zn) were observed for roadside soils. Concentration-dependent magnetic parameters (χ 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 χ and SIRM significantly correspond to elements Ca, Cd, Cu, Pb, and Zn. The χ and SIRM also have significant linear correlation with integrated pollution index, indicating that χ 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.