四川盆地典型农耕区土壤重金属含量、污染及其影响因素

以重庆市江津区为研究区，采集247件表层土壤样品，综合运用污染指数法、GIS和地理探测器等分析方法以便探明四川盆地典型农耕区土壤重金属含量、污染特征及其影响因素.结果表明：(1)表层土壤中Cd、Cu和Zn的算术均值分别是渝西地区土壤背景值的1.22、1.10和1.98倍.(2) 6种重金属含量高值区主要分布于研究区北部、西部和中部局部地区，低值区分布于东部和南部.(3)土壤污染指数整体以安全和警戒为主，内梅罗综合污染指数(NPI)评价显示污染样点占总样点的22.1%,NPI最高值位于北部鼎山街道，最低值位于南部四面山镇.(4)地层对土壤重金属含量分布的单因子解释力最强，其次是地形因子；地层和地形因子对土壤重金属含量分布的交互影响作用最强.研究结果发现地层和地形因子是影响研究区土壤重金属含量分布的关键因素.

Soil Heavy Metal Content, Pollution, and Influencing Factors in Typical Farming Area of Sichuan Basin

In order to identify heavy metal contents, the pollution characteristics and influencing factors of soil in typical farming areas in the Sichuan basin were analyzed, with Jiangjin District of Chongqing City chosen as the study area. Two hundred and forty-seven topsoil samples were collected and analyzed using the Nemerow index (NPI), geographical information system (GIS), and geodetector method. The results demonstrated that: 1 the arithmetic means of Cd, Cu, and Zn in the topsoil were 1.22, 1.10, and 1.98 times that of the soil background values in western Chongqing, respectively. 2 The high-value areas of the six heavy metals were mainly distributed in the northern, western, and central Jiangjin district, whereas the low-value areas were distributed in the eastern and southern Jiangjin district. 3 The NPI showed that the polluted sample points accounted for 22.1% of the total sample points, indicating that the overall soil pollution was mainly safety and vigilance in general. The high value of NPI was distributed in Dingshan street in the northern Jiangjin district. 4 The explanatory power of stratum on the distribution of heavy metal contents in the topsoil was the strongest, followed by that of the topographic factor. The interaction effect of the stratum and topographic factors on the distribution of heavy metal content in soil was the strongest. The results showed that the stratum and topographic factors were the key factors affecting the distribution of soil heavy metal contents in the study area.