基于地理探测器的封丘县农田土壤重金属分布影响因素研究

Study on Factors Influencing Heavy Metal of Farmland Soils Based on Geographical Detector in Fengqiu County

以河南省封丘县为研究区,利用反距离加权插值法研究了农田土壤重金属Cd、Cu、Cr、Pb、Zn和As的空间分布特征;同时,应用基于地理探测器模型定量研究了8个因子对土壤重金属空间分布的影响。结果表明:研究区土壤Cd、Cr、Pb和Zn含量超过了黄河下游潮土背景值,而Cu和As含量低于黄河下游潮土背景值;其中有极少量样点Cd含量超过农用地土壤污染风险筛选值,而其他均未超标。在空间分布上,Cd、Cr、Pb含量的高值区分别主要分布在研究区中部、西南部和北部,As含量的高值区分布在研究区北部和西南部,Cu和Zn含量的高值区在研究区南北方向呈带状分布。Cd、Pb和As含量的低值区主要分布在研究区南部,Cr、Cu、Zn和As含量的低值区主要分布在研究区中部。地理探测器分析表明,土壤重金属空间分布受到自然因子和人为因子的共同作用,有机质含量是影响较大的自然因子,人口密度是影响较大的人为因子。两因子之间的交互作用均大于单因子的作用,其中有机质含量与各因子的交互作用对重金属空间分布的影响较显著。

The spatial distribution of Cd,Cu,Cr,Pb,Zn and As in cropland in Fengqiu County of Henan Province were explored based on inverse distance weighted interpolation method.Simultaneously,the geographical detector model was adopted to illustrate the effects of 8 influencing factors on heavy metal spatial distribution.The results show that the average contents of Cd,Cr,Pb and Zn are higher while Cu and As are lower than the background values of the fluvo-aquic soil in the lower Yellow River.All heavy metal contents in soil are lower than the allowable values for agricultural land except for Cd from few samples.The high-values of Cd,Cr,and Pb are distributed in the middle,southwest and north,respectively,while As is distributed in the north and southwest.The high-values of Cu and Zn are shown in zonal distribution.The low-values of Cd,Pb and As are mainly distributed in the south,and the low-values of Cr,Cu,Zn and As mainly distributed in the middle.According to the geo-detector model,the spatial distribution of heavy metals is influenced by both the natural and artificial factors,among of which,soil organic matter content is a dominant natural factor,while the population density is the primary artificial one.The interaction effect of each two factors is greater than that of single factor,especially the interaction between soil organic matter and other factors.