基于EBK插值预测和GDM模型的襄州区耕地土壤重金属时空分布及来源变化分析

为探讨襄州区重金属空间格局时空变化及其来源变化，于2009年11月和2019年11月分别在襄州区耕地土壤采集395个和326个土壤样品，测得两年铬（Cr）、铅（Pb）、砷（As）、汞（Hg）和镉（Cd）含量，采用经验贝叶斯克里金法（EBK）得出两年5种土壤重金属含量空间格局情况及变化量分布情况，并利用地理探测器模型（GDM）计算19种环境因子和5种重金属含量q解释力并比较两年变化情况.结果表明，与2009年相比，2019年襄州区Cr、Pb、Hg和As这4种土壤重金属含量整体趋于降低，Cd整体含量增加；2019年襄州区土壤重金属含量空间分异情况较2009年趋于复杂，Pb、Hg和Cd在南部、Hg在中部市区及周边地区也表现为含量增加；各元素向北及西北部地区表现为含量降低.2019年自然因子和污染企业距离对5种土壤重金属含量单因子解释力均有所下降，且单因子主控下对其含量的影响力显著性降低，而人类活动因子尤其是居民点用地距离、道路距离、污染企业用地和环境因子对土壤重金属元素的叠加影响力增强.说明2019年土壤重金属来源变化由以结构性因素为主要影响因素趋于复杂，污染企业的排放对重金属元素影响力降低，而人类活动对重金属含量影响增加.

Spatial and Temporal Distribution and Source Variation of Heavy Metals in Cultivated Land Soil of Xiangzhou District Based on EBK Interpolation Prediction and GDM Model

In order to explore the spatial and temporal changes in spatial patterns and source changes in heavy metals in Xiangzhou District, 395 and 326 soil samples were collected from cultivated soil in Xiangzhou District in November 2009 and November 2019, respectively. The contents of Cr, Pb, As, Hg, and Cd during these two years were measured. The spatial pattern and variation distribution of five types of heavy metals during these two years were obtained by using the empirical Bayesian Kriging (EBK) method. The effect (q-statistic) of 19 environmental factors and 5 types of heavy metals was calculated by using the geographical detector model (GDM), and the changes over the two years were compared. The results showed that compared with that in 2009, the heavy metal contents of Cr, Pb, Hg, and As in Xiangzhou District were decreased as a whole in 2019, whereas the Cd content increased overall. The spatial differentiation of heavy metals in the soil in Xiangzhou District in 2019 was more complicated than that in 2009. Pb, Hg, and Cd in the south and Hg in the central urban area and surrounding areas also increased. The content of each element decreased to the north and northwest. Compared with that in 2009, the explanatory power of natural factors and the distance between pollution enterprises on the single factor of the five soil heavy metal contents in 2019 decreased, and the influence on the contents under the control of single factors decreased significantly. The superposition influence of human activity factors increased, especially the distance between residential land, road, and land for pollution enterprises and environmental factors on soil heavy metal elements. These results indicated that the changes in soil heavy metal sources in 2019 tended to be complex, with structural factors as the main influencing factor. The influence of the emission of polluting enterprises on heavy metal elements decreased, whereas the influence of human activities on heavy metal content increased.