Papers by Keyword: Street Dust

Abstract: Study on the elemental composition of nanoparticles is of great importance due to their high mobility in the environment and ability to penetrate into human organism. A global aspect is the transport of nutrient and toxic elements with environmental nanoparticles, which can serve as a carrier for these elements. Nanoparticles in complex polydisperse environmental samples such as dust, volcanic ash, or soil may represent only about thousandths or less of bulk sample. Therefore, their recovery followed by quantitative determination of analytes is a difficult task. A novel technique, sedimentation field-flow fractionation in a rotating coiled column, was applied to the fractionation of urban dust and volcanic ash samples with water being used as a carrier fluid. nanoand submicron particles have been separated, weighted, characterized by electronic microscopy and static laser light scattering, and then quantitatively analyzed by ICP-AES and ICP-MS (after digestion). In urban street dust samples, the elements that may be of anthropogenic origin (Zn, Cr, Ni, Cu, Cd, Sn, Pb) were found to concentrate mainly in <0.3 and 0.3-1 μm fractions. It has been shown that the concentrations of Cr, Ni, Zn, Pb, Sn in the finest fraction (<0.3 μm) of street dust can be one order of magnitude higher than the concentrations of elements in bulk sample and coarse fractions. For volcanic ash samples, it has been evaluated that nanoparticles may concentrate potentially toxic elements of volcanic gases. The concentrations of Zn, Cu, Pb, Tl, Bi, Sn, As, Sb in the size fraction <0.2 μm can be two orders of magnitude higher than the concentrations of these elements in bulk sample. Hence, measuring the total concentrations of elements in dust and ash leads to underestimation of the hazard of these samples. The proposed approach to the separation and quantitative analysis of environmental nanoparticles can be a powerful tool for risk assessment related to toxic elements in dust, ash, and other particulate matter.

Abstract: Sequential extraction was used to characteristic the heavy metals (Cd, Cr, Zn, Cu, Ni and Pb) and trace element (As) studied in these urban dusts. The ratio of the average total content (F1+F2+F3+F4+R) to the corresponding background value of Beijing soil decreased in the order of Cd>Pb>Cu>Zn>Ni>Cr>As. For fraction distribution, residual form predominated among for Zn, Ni, Cr and Pb. Oxidizable fraction was the leading fraction for Cd and Cu and was the second dominated fraction for Zn and Ni. The results of Risk assessment code (RAC) showed the medium environmental risk of Cd was found in Dongcheng and East 4thRing districts, while a high environmental risk for Cr was present in Xizhimen and Yongdingmen areas.

Abstract: Most studies about urban street dust have been focused on big cities so far and less attention has been focused on small towns. In this paper, we collected 12 samples from four different localities (Commercial Area, Industrial Area, Shuangzhu Street, Xuefu Road) in small towns of Yongchuan District, Chongqing to investigate the concentration distribution and composition of nitrogen in street dust. The results revealed that dust samples from Commercial Area contain higher concentration of total nitrogen (TN) (e.g., 1672mg/kg) comparing with dust samples from other three sites (e.g., 196-682mg/kg). In addition, inorganic nitrogen was the predominant form in every site and accounted for 67%-89% of TN. Organic carbon (OC) and pH also had an effect on concentration and composition of TN.

Abstract: Most studies about urban street dust have been focused on big cities so far and less attention has been focused on small towns. In this paper, we collected 12 samples from four different localities (Commercial Area, Industrial Area, Shuangzhu Street, Xuefu Road) in small towns of Yongchuan District, Chongqing to investigate the concentration distribution and composition of phosphorus in street dust. The results reveal that dust samples from Commercial Area contain higher concentration of total phosphorus (TP) (e.g., 785mg/kg) comparing with dust samples from other three sites (e.g., 310-400mg/kg). The research also indicates that the size fraction plays an important role in the concentration distribution of TP. The smaller size fraction corresponds to higher TP concentration. In addition, Ca-P is the predominant form in every site and accounts for 66%-89% of TP. Organic carbon (OC) and pH also have an effect on concentration and composition of TP.

Abstract: By the investigation of 23 samples from street pavement dust in Suzhou city, this article analyzed the the particle size distribution characteristics of lead in street dust, using the X-Ray fluorescence spectrometry and single factor method. The results show that: the lead concentrations in the particle size ranges of <75μm and 75-150μm are higher than the other ranges, which indicates lead is enriched in fine grain size; the particle size ranges of 250-500μm is at mild level of lead pollution, and the other particle size ranges are at medium level.

Abstract: After selecting 23 samples from street pavement dust in Suzhou city, this article analyzed the Zn content in street dust with X-RF fluorescence spectrometer analysis and carried on the ecological risk evaluation. The results show that the Zn content in Suzhou street dusts is from 121 to 538 (mg / kg), and distribution characterized of different functional areas as follows: the business district > the vicinity of the station>the rest area of culture and education > the residential area> the industrial area; the accumulation index values is between 0.76 and 1.78, which is non-polluting or moderately polluted.

Abstract: A preconcentration method based on the adsorption of palladium-dimethylglyoxime -anchored organobentonite (DMG-bentonite) for the determination of palladium at trace levels by flame atomic absorption spectrometry (AAS) has been developed. The optimum experimental parameters for the adsorption and preconcentration of the palladium, such as pH value of medium, contact time, eluent and coexisting ion, have been investigated. The results showed that the palladium ion could be quantitatively retained by the DMG-bentonite in the pH range of 3–5 using citric acid/citrate buffer, the adsorption time was 20 min, and capability of adsorption was 8.73 mg•g-1. The palladium ion adsorbed on the DMG-bentonite could be completely eluated by using 1 mol•L-1 HCl. The detection limits of this method for palladium was 1.02µg•L-1 with an enrichment factor of 60. The method has been applied to the determination of trace amounts of palladium ion in street dust and environmental water with satisfactory results.