Spatial distribution of hazardous elements in urban topsoils surrounding Xi'an industrial areas, (NW, China): Controlling factors and contamination assessments

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.