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Dytłow, Sylwia
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- PublicationRestrictedMagnetic, geochemical and granulometric properties of street dust from Warsaw (Poland)The study presents variations in the magnetic properties and heavy metal concentrations of five granulometric fractions, i.e. 1000–500 μm, 500–250 μm, 250–100 μm, 100–71 μm and <71 μm, for street dust collected at two locations in Warsaw. Combination of grain-size determination, magnetometry, electron microscope observation, mineral composition and chemical analyses was applied as an effective and multidisciplinary approach for the complete characterization of individual fractions of street dust. The magnetic properties of street dust are influenced by its grain size; concentration-dependent magnetic parameters, e.g. magnetic susceptibility, saturation magnetization, saturation remanence and anhysteretic remament magnetization of the finest fraction (d < 0.071 mm) are about three times higher than that of the coarsest fraction (d > 0.5 mm). For all fractions the main magnetic mineral is near stoichiometric magnetite. The dust fractions with grain size <250 μm additionally contain a phase with a Curie point ~770 °C, ascribable to metallic iron. The smallest contribution to the total mass is from the finest size fractions, which contain the highest concentrations of the traffic-related heavy metals. Traffic intensity are well reflected at the two sites studied by the concentration of anthropogenic magnetic particles which are strongly associated with traffic-related heavy metals. Magnetic extracts of the finest dust fraction contain a mixture of spherical magnetic particles and irregular angular particles of iron-oxides with traces of Mg, Al, Na, Ca, K, and Si. Detailed studies preferentially oriented toward to the finest fractions of street dust are a critical issue in terms of potential effects on population health.
475 5 - PublicationOpen AccessIntegrated Magnetic Analyses for the Discrimination of Urban and Industrial Dusts(2020)
; ; ; ; ; ; ; ; ; ; ; Industrial and urban dusts were characterized by investigating their magnetic properties. Topsoil composed of technogenic magnetic particles (TMP) originating from areas affected by three ironworks, street dust mainly composed of traffic-related pollution, and particulate matter (PM) from urban agglomeration in Warsaw, Poland were investigated. Several magnetic methods, namely magnetic susceptibility, thermomagnetic curves, hysteresis loops, decomposition of isothermal remanent magnetization acquisition curves, and first-order reversal curves, were performed to evaluate the magnetic fraction of dust. Magnetite was the main magnetic phase in all types of samples, with a small amount of high-coercive hematite within ironworks and street dust samples. Significant differences were observed in the domain structure (grain size) of industrial and traffic-related magnetic particles. The grain size of TMP obtained from steel production was in the range of 5–20 µm and was predominated by a mixture of single-domain (SD) and multidomain (MD) grains, with the prevalence of SD grains in the topsoil affected by Třinec ironwork. The traffic-related dust contained finer grains with a size of about 0.1 µm, which is characteristic of the pseudo-single-domain (PSD)/SD threshold. Street dusts were composed of a slightly higher proportion of MD grains, while PM also revealed the typical behavior of superparamagnetic particles.387 169