Soil Heavy Metal Pollution Assessment Of Taiyuan City Based On Support Vector Machine

Urban expansion, industry development and population explosion have brought increasing risk for the land ecosystem of suburban. This paper, focusing on soil quality risk assessment, taking Taiyuan city, Shanxi province as research area, explored the statistical characterization and spatial pattern of soil heavy metals and soil nutrients firstly, and then used Support Vector Machine (SVM) model to assess the soil heavy metal pollution and soil quality. Finally, this paper discussed the relationships between soil heavy metal pollution and industrial pollution sources. The results were as follows:(1) The standard deviations of soil heavy metals Cu, Zn, Cr, Pb and soil nutrients available nitrogen, available phosphorus, available potassium were higher, which showed that the variation of these variables were larger. The correlations among soil heavy metals were significant and positive except As; and the correlations among soil nutrients were positively significant.(2) The pollution of Cu, Zn, Ni, Pb, and Cd was more serious in Xiaodian District, and the pollution of Cu, Pb, and Hg was more serious in Jinyuan District. The soils in Wanbailin District and north of Xiaodian District were with higher soil nutrients contents, and those of Xinghualing District were with lower soil nutrients contents.(3) Except available potassium, other soil elements had no significant differences among different land use types (P> 0.05).(4) The assessment results of soil heavy metal pollution based on SVM showed that the soil heavy metal pollution was more serious in the south of Taiyuan; and, the assessment results of soil quality showed that the soil quality was better in Xinghualing district and parts of Wanbailin district.(5) Pollution source types could significantly affect the concentrations of soil heavy metals Zn, Pb, Cd, and, Hg; and, chemical industrial pollution sources and coal mineral pollution sources were the mainly pollution sources types which were needed to govern and manage intensively, they could bring about pollution of many soil heavy metals.The results of this paper had theoretical and practical meaning. Theoretically, it verified the applicability and superiority of SVM in ecological risk assessment, and remedied the disadvantages of typical assessment methods.Practically, the results displayed the soil heavy metal pollution and soil quality situation, and it could provide some references for related departments.