滇中姚安地区土壤重（类）金属来源分析及生态风险评价

为了解滇中姚安地区表层土壤重（类）金属的污染特征、来源及生态风险状况，在研究区共采集表层土壤样品428件，对其中As、Cd、Cr、Cu、Hg、Ni、Pb和Zn元素的含量进行测试分析。通过数据统计分析和地球化学图说明了这些重（类）金属元素的含量分布特征和空间分布特征。运用相关性分析、主成分分析和聚类分析方法探究了重（类）金属的来源。运用地累积指数法、富集系数法和潜在生态危害指数法对研究区土壤重（类）金属污染程度及潜在生态风险进行了评价。研究结果表明，As、Cu、Pb和Zn受自然背景与矿产开采共同影响；Cr、Ni主要来源于成土母质；而Cd受矿产开采和农业施肥的影响较大；Hg则受周边工厂以及煤炭燃烧的影响。地累积指数和富集系数分析表明，研究区污染程度普遍不高，但局部地区有重（类）金属元素的污染富集，代表元素为Cd和Hg。而潜在生态危害指数法分析结果也表明Cd和Hg是研究区最主要的风险元素，但以轻度和中度生态危害为主，强生态危害分布面积较小，研究区生态风险整体较低，风险可控。本研究对滇中地区的土壤重（类）金属的污染评价和土地利用发展规划有一定的参考作用。

Sources analysis and ecological risk assessment of soil heavy metals and metalloids in Yao'an area of central Yunnan

A suite of 428 surface soil samples were collected in the Yao'an area of central Yunnan area to evaluate the pollution characteristics, sources, and ecological risks associated with the heavy metals and metalloids such as As, Cd, Cr, Cu, Hg, Ni, Pb and Zn. The concentrations and spatial distribution characteristics of these heavy metal elements are illustrated through statistical data analysis and geochemical maps. The sources of heavy metals and metalloids were explored using correlation analysis, principal component analysis, and cluster analysis methods. The degree of heavy metal pollution and potential ecological risks were evaluated by the geo-accumulation index method, the enrichment factor method, and the potential ecological risk index method. The results show that As, Cu, Pb and Zn are influenced by the natural background and mineral mining. Cr and Ni mainly reflect soil parent materials; Cd enrichment is associated with mineral mining and agricultural fertilizer use. Hg is affected by surrounding factory emissions and coal combustion. The analysis of the Geo-accumulation Index and Enrichment Factor showed that the pollution degree in the study area was generally not high; however, there was local enrichment of the heavy metals such as Cd and Hg. The potential ecological risk index method also showed that Cd and Hg are the most important risk elements in the study area, but they are mainly mild and moderate ecological hazards. The distribution area of strong ecological hazards is small, and the overall ecological risk in the study area is low and controllable. Our study provides a current assessment of soil heavy metal and metalloid pollution in the study area that can be used to guide future land-using plan in central Yunnan.