Heavy Metal Accumulation Sequences And Environmental Kuznets Curve Of Tree-Rings In Kaifeng

In order to investigate the concentrations, spatial distribution, pollution source , Environmental Kuznets Curve of the heavy metals of tree-rings of P. euramericana in Kaifeng, The author collected 16 trees of 20 years old and its surface soils from different zones, including the school zone , industrial zone , traffic zone, entertainment zone , mixed zone and suburban zone in this paper.The author made following research in this paper:I: The author mainly introduced the current situation and developmental trend of the dendrochemical analysis, and put forward the content and meaning of this paper.II: Mainly introduce the background of the study areas, including the natural environment characteristics, socioeconomic status and pollution condition.III: The sampling selection and site, collecting tree rings and soils, samples pretreatment, experimental projects and determination methods were also introduced in this part.IV: Comprehensively discuss and analyze the heavy metal content, time-series analysis, functional difference, pollution source, Environmental Kuznets Curve of the tree rings from the different functional areasThe main conclusions can be drawn from what has been discussed above:(1) The variability of heavy metal of tree rings in the different domains of Kaifeng was divided into two types, one type ( Cu, Zn Co, Ni, As, Pb) is moderate intensity variation, the other type(Cr, Cd) was strength variation. The Average order of heavy metal elements from the different functional areas were: Cu: mixed zone > industrial zone > traffic zone > school zone > entertainment zone > suburban zone ;Zn: industrial zone > school zone >mixed zone > entertainment zone > suburban zone > traffic zone; Cr: school zone> entertainment zone > traffic zone > industrial zone >mixed zone > suburban zone; Co: entertainment zone > traffic zone > school zone >mixed zone > suburban zone> industrial zone ; Ni: traffic zone > entertainment zone > industrial zone >school zone > suburban zone> mixed zone; As: entertainment zone> school zone > traffic zone > suburban zone > industrial zone >mixed zone; Cd: traffic zone > mixed zone > entertainment zone > school zone >suburban zone > industrial zone; Pb: entertainment zone > traffic zone> school zone > mixed zone > suburban zone > industrial zone .(2) By analyzing the time-series of tree-rings of P. euramericana , the author come to the conclusion that the curve types could be classified as three types: straight or flat type, fluctuation or oscillation type and ascension type. The heavy metal content of tree rings from most of the functional areas were higher than in the suburbs. In recent 20 years, the curves of Cu, Zn, Pb and Cd had a tendency to upward, these four elements contents of poplar in the industrial zone were obviously higher than that of other functional areas of the same period.(3) The correlation analysis of the heavy metals between tess and soils showed that the soil is not the only source of heavy metals in tree rings.The heavy metals would be preserved in the xylem by the leaves and trucks absorbing of atmospheric particulates, which made an important contributions increasing the contents of heavy metals in tree-rings.(4) The Environmental Kuznets Curve between the variation in pollution elements contents of the tree-rings and its surface soils showed that there was a significant cubic polynomial correlation between the elements (Cu, Zn ,Cr, Co, Cd) variation of tree rings in content and the comparable per capita GDP, the curves displayed obviously characteristics of environmental kuznets curve, the correlation coefficient (R2) are larger than 0.693; the regression curve (Cu, Zn, Cr, Co, Cd) was on the left part of the inverted "U" type curve.