As an important component of the urban ecological environment, it is great of significance for urban soil to the sustainable development of a city. However, with the increasing human activities, heavy metals have become significant impact toxic pollutants to the soil in a city. Especially, cadmium (Cd), lead(Pb), copper (Cu) and its complex are more prominent in urban soil pollution. Therefore, in order to explore the content and spatial distribution characteristics of heavy metal pollution in the urban soil, and provide an objective basis for environmental management and environmental protection, in this study, taking Neijiang City as an example, lead (Pb), cadmium (Cd), copper (Cu) and zinc (Zn) of 203 surface soil samples of different land use types are evaluated pollution characteristics and their spatial pollution levels based on ordinary Kriging and Projection Pursuit Model as well as method of single factor pollution index. The results are as follows: (1) The order of enrichment degree was Cd>Zn>Cu, and the Pb was not enriched comparing with the grade-two standard values of national environmental quality standards for soils. (2) The variation coefficient of 4 kind of soil heavy metal elements was highly variable, the content of soil heavy metal was strongly affected by human activities. (3) The order of comprehensive pollution degree of ordinary Kriging was public land>commercial land>residential land > industrial and mining land>agricultural land>traffic land. (4) The pollution grade levels of soil heavy metal in Neijiang City were relatively cleaning,light pollution. The area ratio of spatial distribution between relatively cleaning and slight pollution area was 1.2:1. In general, the comprehensive pollution level of in Neijiang was lighter. Therefore, the Projection Pursuit Model can provide a new idea for involving multiple factors of heavy metal pollution evaluation on soil.%作为城市生态环境的重要组成部分,城市土壤对城市的可持续发展具有重要意义.然而,随着人类活动加剧,重金属元素成为城市土壤中具有重大影响的有毒污染物,尤其是铅(Pb)、镉(Cd)、铜(Cu)及其复合物在城市土壤污染中较为突出.为了探讨城市土壤中重金属的含量及污染空间分布特征,为城市环境治理和环境保护提供客观依据,以内江市城区为例,采集了203个表层土壤样本,利用单因子污染指数法、GIS技术结合投影寻踪模型评估了研究区不同土地利用方式下表层土壤铅(Pb)、镉(Cd)、铜(Cu)、锌(Zn)的污染特征及其空间污染程度.结果表明:(1)与国家二级标准限定值比较,镉元素的富集程度最大,锌元素次之,铜元素富集程度最小,铅元素无富集;(2)4种元素变异系数属于高度变异,其含量均受到人类活动的强烈影响;(3)土壤重金属综合污染指数均值表现为公共用地>商业用地>住宅用地>工矿用地>农业用地>交通用地;(4)内江市城市土壤重金属污染程度的克里格插值评价等级为较清洁、轻污染,在空间展布上二者的面积比例为1.2:1,内江市重金属综合污染水平较轻.投影寻踪模型为涉及多因素的城市土壤重金属污染评价提供了新思路.
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