title: [Spatial and temporal characteristics of heavy metal concentration of surface soil in Hebin Industrial Park in Shizuishan northwest China].
abstract: Concentrations of Zn, Cu, Cr, Pb and Cd in 96 topsoil samples collected from the northern Hebin Industrial Park were measured by the atomic absorption detector (AAD). Spatial variability was identified by geostatistical analysis with the aid of GS + 3.0 and ArcGIS 9.0. Temporal variability of five heavy metals was contrasted to the concentration in 1985 of the Ningxia second soil census. Google earth maps in years of 2003, 2004, 2009 and 2011 have been analyzed to find the variation of the geographical distribution of factories in study Area. Result showed that mean concentrations of Zn, Cu, Cr, Pb and Cd were 100.29, 352.86, 77.56, 50.52, 4.06 mg x kg(-1), respectively, and were all higher than the background values. Using the second level of environmental quality standard for soils of China as the criterion, Zn, Cr, Pb were not risk, Cu, Cd were mild contamination and serious contamination. Spatial distribution of the concentration of the five heavy metals varies with prevailing wind direction, from the northwest to southeast, increasing gradually. Meanwhile, there were several hotspots. Google earth map analysis showed that in the northeast and southeast part appeared a large number of factories after 2009, which should be the main sources of the five heavy metals in soils. In the lowlying southwest part, although there was no factory, soils still have been polluted heavily because of another adjacent industrial area in Inner Mongolia Autonomous Region and the smoke dust was blocked by the Helan Mountain along its west.
  
  
  CONCLUSIONS
  (1) The number of the enterprise increased and trans-boundary pollution led to the high heavy metal concentration in surface soil of study area; (2) In northwest China, because of the strong wind, smoke dusts spread very long and distribution range was extensive, and low terrain area and enterprise distribution pattern lead to the island distribution.
authors.affiliation: College of Agriculture, Ningxia University, Yinchuan 750021, China. fanxg@nxu.edu.cn
authors.forename: Xin-gang
authors.initials: XG
authors.lastname: Fan
authors.forename: Wen-bao
authors.initials: WB
authors.lastname: Mi
authors.forename: Zhen-ning
authors.initials: ZN
authors.lastname: Ma
authors.forename: Ting-yu
authors.initials: TY
authors.lastname: Wang
mesh_terms: D002681:China; D004784:Environmental Monitoring; D019216:Metals, Heavy / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*; D062211:Spatio-Temporal Analysis
chemical_list: D019216:Metals, Heavy; D012989:Soil Pollutants