Size distribution and diffuse pollution impacts of PAHs in street dust in urban streams in the Yangtze River Delta

Particles of dust washed off streets by stormwater are an important pathway of polyaromatic hydrocarbons （PAHs） into urban streams. This article presented a comprehensive assessment of the size distribution of PAHs in street dust particles, the potential risks of the particles in urban streams, and the sources and sinks of PAHs in the stream network. This assessment was based on measurements of 16 PAHs from the USEPA priority list in street dust particles and river sediments in Xincheng, China. The content of total PAHs ranged from 1629 to 8986 Dg/kg in street dust particles, where smaller particles have a higher concentrations. Approximately 55% of the total PAHs were associated with particles less than 250 μm which accounted for 40% of the total mass of street dust. The PAH quantities increased from 2.41 to 46.86 μg/m2 in the sequence of new residential, rising through main roads, old town residential, commercial and industrial areas. The sediments in stream reaches in town were found to be sinks for street dust particle PAHs. The research findings suggested that particle size, land use and the hydrological conditions in the stream network were the factors which most influenced the total loads of PAH in the receiving water bodies.

Assessment of Selected Heavy Metals in Street Dust Samples from Jazan City, KSA （Kingdom of Saudi Arabia）

In this work, Jazan province （Saudi Arabia） was examined for its heavy metals content. Therefore, 15 street dust samples were collected, digested and analyzed in order to investigate the levels of selected heavy metals and propose the causes for the presence of these metals. All collected samples were digested using Leeds Public Analyst method. The concentrations of heavy metals （Fe, Cu, Mn, Zn, Cd, Co and Pb） were analyzed using atomic absorption spectroscopy. Six heavy metals （Fe, Cu, Mn, Zn, Co and Pb） were measured in all samples; the concentration of Cd was not detected in Jazan dust by atomic absorption spectroscopy. The heavy metals levels in Jazan street dust increase according to the following sequence： Fe 〉 Mn 〉 Zn 〉 Cu 〉 Pb 〉 Co. The correlation coefficients and enrichment factors relative to earth crust abundances of heavy metals were calculated in order to predict the possible sources in dust.

Improved source assessment of Si,Al and related mineral components to PM_(10) based on a daily sampling procedure

Samples obtained from an industrialized valley in the East Alpine region were collected daily for a half year and analyzed using X-ray fluorescence to examine the elements Si, Al, Fe, Ca, Mg, Na, K, Zn, P, S and Cl. Some factors affecting the changes of these elements were considered, including time, elemental correlations, weekday, weekend and seasonal changes. Diagnostic analysis provided an insight into a decoupling behavior that occursin siliceous and carbonates minerals. A decrease in Si and Al and an increase in carbonates, Na, K, Zn and P were observed during the cold season. However, a consistently high correlation of Si and Al was observed in all seasons. It was established that such high levels originated from street surface abrasion. The increase in variability and absolute levels of carbonates during the cold season was demonstrated by adding carbonates to the street surface as gritting material to increase the grip on snowy surfaces. A marked increase in Na and Cl was observed in winter which may have been caused by thaw salt that is widely used in winter in Austria. This was associated with a significant increase in K, Zn, and P in the cold season that was the result of domestic space heating with wood. PM10 levels in December were 12 μ/m^3 and were higher than levels detected in July. It was established that such high levels originated from mineral oxides, wood smoke, and inorganic ionic material（s）.

Integration of chemical fractionation, Mosbauer spectrometry, and magnetic methods for identification of Fe phases bonding heavy metals in street dust

Street dust is one of the most important carriers of heavy metals(HMs)originating from natural and anthropogenic sources.The main purpose of the work was to identify which of Fe-bearing phases bind HMs in street dust.Magnetic parameters of the Fe-bearing components,mainly magnetically strong iron oxides,are used to assess the level of HM pollution.Chemical sequential extraction combined with magnetic methods(magnetic susceptibility,magnetization,remanent magnetization)allowed determining the metal-bearing fractions and identifying the iron forms that aremostly associated with traffic-related HMs.The use of Mossbauer spectrometry(MS)supplemented bymagnetic methods(thermomagnetic curves and psarameters of hysteresis loops)enabled precise identification and characterization of iron-containing minerals.The classification of HMs into five chemical fractions differing in mobility and bioaccessibility revealed that iron is most abundant(over 95%)in the residual fraction followed by the reducible fraction.HMs were present in reducible fraction in the following order:Pb>Zn>Mn>Cr>Ni>Fe>Cu,while they bound to the residual fraction in the following order:Fe>Ni>Cr>Mn>Pb>Cu>Zn.The signature of the anthropogenic origin of street dust is the presence of strongly nonstoichiometric and defected grains of magnetite and their porous surface.Magnetite also occurs as an admixture with maghemite,and with a significant proportion of hematite.A distinctive feature of street dust is the presence of metallic iron and iron carbides.Magnetic methods are efficient in the screening test to determine the level ofHMpollution,while MS helps to identify the iron-bearing minerals through the detection of iron.

Magnetic Properties of Street Dust from Chibi City,Hubei Province,China:Its Implications for Urban Environment

Magnetic measurements and heavy metal analyses were performed on street dusts from the main urban area of Chibi（赤壁） City,Hubei（湖北） Province,China.Results revealed that a PSD/MD（pseudo-single-domain/multi-domain） magnetite-like phase dominates the magnetic phases of the street dust.Concentration-related magnetic parameters,such as magnetic susceptibility（χ）,anhysteretic remanent magnetization（ARM）,and saturation isothermal remanent magnetization（SIRM） of samples increased in the main roads but appeared lower in the landscape area of the Lushui（陆水） Lake and closely correlated with the concentration of heavy metal Fe,Cu,and Co,and the correlation coefficients are 0.786 for Fe-χ,0.548 for Cu-χ,and 0.580 for Co-χ,respectively.However,much strong correlations between SIRM and the concentrations of heavy metal suggest that SIRM is a better indicator for heavy metal pollution in the street dust in the study area.The magnetic particles in the street dust are mainly derived from anthropogenic activities,such as vehicle emissions,abrasion of tires,coal combustion,cement works,and building materials.These results make it possible to use magnetic techniques as simple,rapid,and nondestructive tools for assessing the heavy metal pollutions in urbanization process.