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Li X.,Shaanxi Normal University | Feng L.,Shaanxi Police Professional College
Atmospheric Environment | Year: 2012

An investigation on spatial distribution, possible pollution sources, and affecting factors of heavy metals in the urban soils of Weinan (China) was conducted using geographic information system (GIS) technique and multivariate statistics. The results indicated that the levels of 10 heavy metals (Pb, Cr, Ba, Zn, V, Mn, Co, Cu, Ni and As) distribution measured by wavelength dispersive X-ray fluorescence spectrometry (WDXRF) in urban soil of Weinan were As varied from 2.60 to 11.50 mg kg -1, Co was 8.00-14.50 mg kg -1, Cr from 74.90 to 157.00 mg kg -1, Cu from 14.60 to 34.70 mg kg -1, Ba from 413.00 to 1137.60 mg kg -1, Mn from 431.30 to 653.70 mg kg -1, Ni from 20.80 to 35.8 mg kg -1, Pb from 19.00 to 89.50 mg kg -1, V from 63.80 to 89.50 mg kg -1, Zn from 44.50 to 196.80 mg kg -1, respectively. The mean enrichment factors (EFs) decreased in the order of Pb > Cr > Ba > Cu > Zn > Ni > V > Mn > Co > As, indicating Ba, Cu, Pb, Cr and Zn were significant enriched in the study areas. Spatial distribution maps of heavy metal contents, based on geostatistical analysis and GIS mapping, indicated that Pb and Cr had similar patterns of spatial distribution, likewise, between Ba, Cu and Zn, and among As, Co, Mn, V as well. Multivariate statistical analysis (correlation analysis, principal component analysis, and clustering analysis) showed distinctly different associations among the studied metals, suggesting that the heavy metals, Ba, Cu, Pb, Cr and Zn were associated with anthropic activities (industrial sources, combined with coal combustion as well as traffic factor), whereas Mn, V, Co, As and Ni in study area mainly controlled by parent materials and therefore had natural sources. A comprehensive environmental management strategy should be concerned by the local government to address soil pollution in urban areas. © 2011 Elsevier Ltd.


Li X.,Shaanxi Normal University | Feng L.,Shaanxi Police Professional College
Environmental Earth Sciences | Year: 2012

The concentrations of metals (Pb, Cr, Ba, Zn, V, Mn, Co, Cu, Ni and As) in 38 soil samples collected from the industrial district in Weinan (NW China) were determined by wavelength dispersive X-ray fluorescence spectrometry. The magnetic parameters of soil including low-/high-frequency susceptibility and frequency-dependent susceptibility were measured. The modified three-step BCR sequential extraction procedure was used to evaluate mobility, availability and persistence of trace elements in urban soil samples. Multivariate (principal component analysis, clustering analysis and correlation analysis) and geostatistical analysis (ArcGIS tools) were applied to the obtained data to evaluate the analytical results and to identify the possible pollution sources of metals as well as geo-spatial distributions. The results revealed that the sampling area was mainly influenced by two main sources: (1) Ba, Cu, Pb, Cr and Zn were mainly derived from industrial sources, which combined with coal combustion as well as traffic factor. The mobility sequence based on the sum of the BCR sequential extraction stages was: Pb (53. 79 %) > Zn (51. 78 %) > Cu (50. 96 %) > Ba (42. 59 %) > Cr (18. 47 %). Pb was the metal predominantly associated (~46. 86 %) with the form bound to Fe/Mn oxides, and the highest percentage of Zn was exchangeable and carbonate-bound fraction. Cu was present mainly in organic fraction, while the residual fraction was the most dominant solid phase pool of Cr (~81. 53 %) and Ba (~57. 41 %). (2) Mn, V, Co, As and Ni in the study area were consistently from natural sources. The analysis of enrichment factors indicated that urban soils in Weinan City were classified as having significant enrichment by Ba, Cu, Pb, Cr and Zn. The overall results proposed the future tactics for Weinan environment quality control on a local scale that concerned not only the levels of risky, but also the industrial emission abatement techniques as well as urban setting. © 2012 Springer-Verlag.


Li X.,Shaanxi Normal University | Feng L.,Shaanxi Police Professional College | Huang C.,Shaanxi Normal University | Yan X.,Shaanxi Normal University | Zhang X.,Shaanxi Normal University
Atmospheric Environment | Year: 2014

Atmospheric fallouts (AFs) were collected in the south of Xi'an, NW China, during the dust episodes of 2001-2012. The chemical characteristics of total 68 AF samples including their chemical compositions, size distribution and magnetic susceptibility were studied. The contamination degree and the source of heavy metals in AF were also explored with enrichment factor method and multivariate statistical analysis. The results showed that the particle mass size distribution of AFs dominated by coarse particles (PM10-50) in dust days. The concentrations of 26 elements associated with AFs determined by wavelength dispersive X-ray fluorescence spectrometry (WDXRF) in studied sites varied from 92.90 to 188.10mgkg-1 for Cr, 31.40 and 63.00mgkg-1 for Cu, 16.60 to 167.30 for Pb and 106.60 to 196.80 for Zn. Their average concentrations found in this study were 139.22±29.41mgkg-1, 46.93±10.56mgkg-1, 78.42±46.52mgkg-1 and 150.61±32.84mgkg-1, respectively, which exceeded their corresponding recommended background values more than two times. While, other elements, such as Br varied from 1.10 to 5.90 with 3.34±1.60mgkg-1 mean, Cs from 2.90 to 10.90 with mean of 7.23±2.47mgkg-1, Ga between 6.90 and 20.80 with 15.23±3.59mgkg-1, Rb in the range of 62.10-124.20 with the average of 80.69±16.89mgkg-1, Y from 9.90 to 35.00 with 20.43±6.27mgkg-1 average, La from 29.60 to 54.20 with mean of 37.28±8.28mgkg-1 and V with average of 81.97±8.93mgkg-1 in the 57.7-92.10mgkg-1. Multivariate statistical analysis (principal component analysis and clustering analysis) was suggested that the principal element elements, Al, Fe, Si, K, Ca, Na, Mg, coupled with the trace elements Co, V, Ce, Mn, Ni, Ga, Y, Rb, La, Br, Cs were predominated by crustal material sources, whereas, Cr, Cu, Ba, Sr, As, Pb and Zn were highly influenced by anthropogenic activities. Simultaneously, the water-soluble ions (WS-ions) of NH4 +, SO4 2-, SO3 2-, NO3 -, SiO4 4-, HSO4 - contained in APs identified by FT-IR spectroscopy were possible originated from coal combustion. The results were also confirmed and consistent with the observations of magnetic susceptibility (MS), enrichment factor (EFs) and contamination evaluation analysis. With such rates of atmospheric fallouts that contain elevated levels of toxic elements during the dust storm condition, actions should be taken to continually examine and understand of the potential impacts of AFs on surface ecosystem, water resource, and human health in the dust storm condition. © 2013 Elsevier Ltd.


Li X.,Shaanxi Normal University | Li X.,Jackson State University | Feng L.,Shaanxi Police Professional College
Journal of Hazardous Materials | Year: 2010

Understanding of the hazardous in urban soil and their anthropogenic effect from urban industrial areas is important for urban environmental management and protection. In this study, a total of 44 soil samples were collected from Xi'an western industrial areas, NW, China, and the concentrations of 29 elements were measured by wavelength dispersive X-ray fluorescence (WDXRF) spectrometry. The sources of hazardous metals were conducted through multivariate statistical methods (principal component analysis, clustering analysis, and correlation analysis). The dangerous metals' influences on the environment were evaluated from Nemero Synthesis Index Method and Geostatistical Analysis. All the results indicated the multivariate statistical methods had successfully classified three factors of heavy metals from different sources, of which 36.40% accounted for industrial activities and exhaust emissions, 32.09% for agricultural as well as the precipitant of gas stream, and 31.51% for coal combustion factor. Through the pollution evaluation and the further spatial analysis, the hazardous metals distributed consistently with prevailing NW-SE local wind direction, strongly polluted the urban soil and potentially affected environmental quality and health of Xi'an urban city, especially Bi, Pb, Zn, Sb, and Sn. The results advocated the future tactics for Xi'an environment quality control on a local scale had to concern not only the levels of hazardous but also the industrial emission abatement techniques and urban setting and plan. © 2009 Elsevier B.V. All rights reserved.


Li X.,Shaanxi Normal University | Feng L.,Shaanxi Police Professional College | Huang C.,Shaanxi Normal University | Yan X.,Shaanxi Normal University | Zhang X.,Shaanxi Normal University
Environmental Earth Sciences | Year: 2014

Atmospheric pollution from atmospheric particulate matter (APM) deposition is one of the major sources of potential hazardous elements (PHEs) contamination. In this study, 68 total APM samples were collected from the local areas of southern Xi'an (NW China) during the long-term period of the 2001-2012 dust campaign. The chemical fractionation of PHEs (Cr, Cu, Ba, Sr, As, Pb, and Zn), their contamination levels, and ecological health risk were examined. The mobility sequence based on the sums of the first three fractionations of the modified BCR (the European Community Bureau of Reference) sequential extraction stages was: Cu (77.83 %) > Pb (74.50 %) > Zn (55.40) > Sr (52.93) > Ba (40.89) > Cr (30.09) > As (21.59). The contamination levels of APMs from these sites, calculated from the total content indices ICF, were uniformly moderate in degree. The obtained single-metal model MIMERSS (speciation index) values had allowed for classification of elements as a function of their potential ecological risk as As (64.00 mean value) > Pb (43.86) > Sr (37.50) > Cu (11.53) ≅ Ba (11.32) > Zn (7.68) > Cr (1.88). The results presented that the toxic As posed a moderate to considerable risk; Pb and Sr varied from low to a moderate risk, while others posed low risk. However, a new developed multi-metal model GRIIERMS (speciation index) indicated that the PHEs in most of the APMs posed moderate ecological risk. The result was consistent with that of ICF indexes. Combined with the US Environmental Protection Agency, we developed models of (ingestion, dermal and inhalation) hazard index (HI), children's health risk due to PHEs exposure from APM was higher than that for adults. Much attention should be paid to the PHE As (HI = 0.864, close to 1) for children. While, carcinogenic risk for adults was higher than that for children. Although cancer risk because of As, Cr and Pb exposure were within an acceptable range, the PHEs exposed to the highest density of the population in residential and educational villages in south of Xi'an would be much more concerned. The moderate ecological risk and the higher risk for children's health illustrated that special attention has to be taken to the mentioned PHEs from APMs in the local ecosystem, and their health risk impact should continue to be checked carefully. The new developed GRIIERMS index method was to be useful for risk assessment of PHEs combining with their chemical fractionations. © 2013 Springer-Verlag Berlin Heidelberg.

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