长江三角洲地区土壤盐酸可提取态重金属含量的空间变异特征

以江苏昆山市为典型区，对长三角地区土壤盐酸可提取态重金属含量的结构特征进行分析，得出该区盐酸可提取态重金属的空间分布格局并揭示了引起这种分布格局的成因和污染来源，结果表明：昆山市盐酸可提取态Cd、Cr、Cu、Pb、Zn、Hg属强变异，Ni和Co为中等变异。半方差函数模型拟合表明所有盐酸可提取态重金属元素均符合球状模型，8种重金属元素在一定范围内均存在空间相关性。采用Kriging最优内插法得到了盐酸可提取态重金属含量的空间分布格局，表明土壤盐酸可提取态重金属含量与工业活动、污水灌溉和大气降尘密切相关。通过主成分分析与地统计学相结合的方法，得出该区盐酸可提取态重金属由4个主成分构成，第一主成分为Cd、Cu、Pb、Cr和Zn，决定这一成分的主要因素为工业污水灌溉、大气降尘和元素地球化学特征；第二主成分为Ni，决定这一成分的主要因素为土壤内部因子；第三主成分为Hg，该成分主要受工业点源污染的影响；第四主成分为Co，该成分可能主要受地形影响。

Spatial variability of soil hydrochloric acid extractable heavy metals in the Yangtze River Delta

Spatial variability characteristics of soil hydrochloric acid extractable metals(Cd, Cr, Cu, Ni, Hg, Pb, Zn and Co) in the topsoil(0~20 cm) from Kunshan City, the typical region of Yangtze River delta, were analyzed by geostatistical method, and the spatial distribution and its pollution source and cause of heavy metals were discussed. Results show that hydrochloric acid extractable Cd, Cr, Cu, Pb, Zn, Hg are strong variability, while Ni and Co are medium variability. Semivariance analysis show that all the hydrochloric acid extractable heavy metals are fitted for spherical model, and the concentrations of eight heavy metals are correlated in a given spatial range. Kriging interpolation method was applied to estimate the heavy metal concentrations of the unobserved points and their spatial distribution maps were obtained, which indicates that the concentrations of soil hydrochloric acid extractable metal have a close relationship with industry activity, sewage irrigation and atmosphere deposit. Combined principal component analysis with geostatistics, soil hydrochloric acid extractable metals in Kunshan City were composed by four components, and the first component(Cd, Cu, Pb, Cr, Zn) is affected by industrial sewage irrigation, atmosphere deposit and geochemistry feature of element; the second component(Ni) is influenced by soil intrinsic factor, the third component(Hg) relates with industry pollution sources, and the fourth component(Co) is probably affected by topography.