巢湖流域典型农田土壤重金属污染评价与地理探测分析

为了分析巢湖流域农田土壤重金属污染特点,选择位于巢湖西部的A村进行了实地土壤样品采集,利用XRay荧光光谱仪对Zn、Cr、Cd、Hg、Pb、As、Cu、Ni 8种重金属元素进行测定,利用污染指数法和潜在生态风险指数法,对土壤重金属污染程度、空间分布和潜在生态风险进行评价。为了进一步分析土壤重金属污染的来源,采用主成分分析和聚类分析对重金属来源进行分类;利用地理探测器,选择高程、距铁路距离、距村庄距离、距公路距离、距水库距离和农用地分类作为变量因子,分析其与重金属污染分布的空间相关关系。研究结果表明,A村主要受到Hg(P_i17.2)、Cd(Pi10.3)污染;Pb、Cu、Zn、Ni主要来自成土母质源,Hg、Cr、Cd、As主要来自人为污染源;农用地类型(PD,H=0.405)和铁路分布(PD,H=0.362)对污染分布的解释力最强,Hg、Cd污染可能来自耕地、畜禽饲养和铁路运输污染,污水灌溉也会一定程度影响重金属污染空间分布。

Assessment and Geographical Detection of Heavy Metal Pollution in Typical Farmland Soil in Chaohu Lake Basin

In order to analyze the characteristics of heavy metal pollution in farmland soil of Chaohu Lake Basin, a village located in the west of Chaohu Lake was selected to collect soil samples in the field. The contents of heavy metals of Zn, Cr, Cd, Hg, Pb, As, Cu and Ni were determined by X-Ray fluorescence spectrometer. The pollution index method and potential ecological risk index method were used to evaluate the degree, spatial distribution and potential ecological risk of heavy metal pollution in soil. In order to further analyze the sources of soil heavy metal pollution, the sources of heavy metals were classified by principal component analysis and cluster analysis. Village DEM, railway buffer zone, village buffer zone, highway buffer zone, reservoir buffer zone and agricultural land classification were selected as variable factors to analyze their spatial correlation with the distribution of heavy metal pollution by using geographical detector. The results showed that a village was mainly polluted by Hg (Pi>17.2) and Cd (Pi>10.3). The main source of Pb, Cu, Zn and Ni was from the parent material of soil forming material. The source of Hg, Cr, Cd and As was mainly from the anthropogenic source of pollution. The type of agricultural land (PD,H=0.405) and railway distribution (PD,H=0.362) had the strongest explanatory power to the distribution of pollution. The pollution of Hg and Cd may come from cultivated land, livestock and poultry breeding land and railway. Sewage irrigation would also affect the spatial distribution of heavy metal pollution to some extent.