关中地区日光温室重金属污染及其田块尺度下的特征

Assessment of greenhouse heavy metal pollution in Guanzhong area and analysis of its spatial distribution on field scale using Geo-statistical software

对关中地区8个日光温室集中分布区域土壤重金属污染进行了调查,并比较了两个相同年限相近位置日光温室污染分布特征,在田块尺度下应用ARCGIS软件地统计学模块进行了插值模型分析。结果表明,8个日光温室采样点污染负荷指数（PLI）在1.087-1.723之间,均为中等污染;区域PLI值为1.311,区域日光温室土壤重金属为中等污染。地统计学插值图表明1号日光温室Cd,2号日光温室Cd、Cu、Pb均出现不同程度累积。在田块尺度下,日光温室1中Cd上层土壤分布高于下层,Cr、Cu和Pb在0-1 m土壤随机分布;日光温室2中Cd和Cu上层土壤分布高于下层,Pb和Cr下层土壤分布高于上层。日光温室重金属污染具有复杂性,即便相同年限相近位置不同日光温室内土壤重金属污染特点也不尽相同。

To assessment the greenhouse heavy metal pollution in Guanzhong area, eight facility agricultural areas were selected to collect soil samples. Two greenhouses from the same place with the same planting years were also selected to analysis the spatial distribution of heavy metals in soil on field scale using Geo - statistical software. Samples were digested with HClO4 - HNO3 - HF and subsequently assayed for Cd, Cr, Cu, Pb by ICP - AES. The findings showed the PLI（Pollution load index） of eight greenhouse soil were 1.403,1. 323,1. 261,1. 258,1. 723,1. 372, 1. 087,1. 152, and the greenhouse soil in Guanzhong area was slightly polluted with PLI 1.311. The method of analysis vertical section of soil spatial distribution of heavy metals on field scale using Geo-statistical software was established. Maps of heavy metals spatial distribution in two greenhouses soil were made using Kriging method. The maps showed the pollutant in No. 1 greenhouse was Cd and in No. 2 greenhouse were Cd, Cu and Pb. At field size, Cd content in No. 1 greenhouse topsoil and Cd and Cu content in No. 2 greenhouse topsoil were both higher than in subsoil, while Pb in No. 2 greenhouse topsoil lower than subsoil. In conclusion, we detected complexity of soil heavy metal pollution of greenhouse, as evidenced by the contrasting mechanism of similar greenhouses.