| 摘要: |
| 【目的】研究陕西关中地区5个小冶炼厂周边农田土壤的重金属污染状况。【方法】采集关中地区5个冶炼厂（S1~S5）周边农田土壤样品，测定重金属Cd、Cr、Cu、Pb含量，分别采用单因子污染指数法和污染负荷指数法对各土壤样品重金属污染程度进行评价，并依据评价结果在田块尺度层面使用地统计学软件对S3冶炼厂周边农田土壤的重金属污染特征进行分析。【结果】关中地区5个小冶炼厂S1~S5周边农田土壤Cd的含量分别为0.74~4.04，0.12~1.36，1.95~32.90，0.21~0.69，0.44~0.70 mg/kg；Cu含量分别为25.7~38.6，21.4~34.3，29.0~59.9，25.1~43.4，32.9~40.9 mg/kg；Pb含量分别为16.0~35.5，11.6~33.4，40.1~78.4，14.1~21.3，32.2~89.1 mg/kg；Cr含量分别为26.8~47.1，29.5~52.0，29.8~51.2，26.1~48.1，23.4~39.3 mg/kg。单因子污染指数法评价结果表明，冶炼厂S3和S1周边农田土壤Cd环境质量指数（Pi）分别为17.8，3.48，处于超标水平；冶炼厂S2、S4和S5 Cd的Pi分别为1.00-，0.73和0.93，均为尚清洁等级；Cr、Cu、Pb元素的Pi均小于0.7，为清洁等级。污染负荷指数法评价结果表明，冶炼厂S1~S5周边农田土壤重金属污染负荷指数分别为2.111，1.486，4.373，1.310和2.039，对应的污染等级分别为强、中等、极强、中等和强。对冶炼厂S3周边农田土壤重金属污染的地统计学研究结果表明，在水平面上距离污染源越近，土壤重金属含量越高；剖面中表层土壤重金属含量越高，下层土壤受到重金属污染的范围越大。【结论】陕西关中地区5个小冶炼厂周边农田土壤中Cd、Pb、Cu均有不同程度富集，且重金属在表层土壤的富集导致深层土壤污染风险加大，关中地区小冶炼厂周边农田重金属污染问题应引起重视。 |
| 关键词: 关中地区 重金属污染 地统计学 小冶炼厂 农田土壤 |
| DOI： |
| 分类号: |
| 基金项目:公益性行业（农业）科研专项（201203045） |
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| Characteristics of soil heavy metal pollution in farmlands near five small smelters in Guanzhong area,Shaanxi |
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HAN Zhongyu,TANG Xiwang,TONG Yan’an
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| Abstract: |
| 【Objective】This study assessed soil heavy metal pollution in farmlands near five small smelters in Guanzhong area.【Method】Farmlands near five smelters (S1-S5) were selected to collect samples for determining Cd,Cr,Cu,and Pb concentrations.Single environment pollution index and pollution load index were used to assess pollution levels. According to the results,one smelter was selected to analyse the spatial distribution of heavy metals in soil on field scale using Geo statistical software.Soil samples were digested with HClO4-HNO3-HF and concentrations of Cd,Cr,Cu,Pb were detected using ICP-AES.【Result】Cd concentrations in soil near smelters S1-S5 were 0.74-4.04,0.12-1.36,1.95-32.90,0.21-0.69 and 0.44-0.70 mg/kg,respectively.Cu concentrations in soil near smelters S1-S5 were 25.7-38.6,21.4-34.3,29.0-59.9,25.1-43.4 and 32.9-40 mg/kg, respectively.Pb concentrations in soil near smelters S1-S5 were 16.0-35.5,11.6-33.4,40.1-78.4,14.1-21.3,and 32.2-89.1 mg/kg,respectively.Cr concentrations in soil near smelters S1-S5 were 26.8-47.1，29.5-52.0，29.8-51.2，26.1-48.1 and 23.4-39.3 mg/kg,respectively.The results of single pollution index showed the Cd Pi indexes for farmlands near S3 and S1 were 17.8 and 3.48,respectively,which were in excessive level compared with the environmental standard.For farmlands near S2,S4,and S5,the Cd Pi indexes were 1.00-,0.73,and 0.93,respectively,which were clean.Pi indexes of Cr,Cu and Pb for farmlands near S1-S5 were all less than 0.7,which were clean.The pollution load indexes for farmlands near S1-S5 were 2.111，1.486，4.373，1.310 and 2.039,respectively,and the corresponding pollution levels were strong,medium,extremely strong,medium and strong compared with the soil background values.The spatial distribution maps indicated the enriched elements of smelter surrounding farmland were Cd，Pb and Cu.The heavy metal concentrations increased when the sampling sites were closer to pollution sources.These elements were mainly distributed in soil top layer.Higher heavy metals concentration in surface soil indicated that deeper soils were polluted. 【Conclusion】The soils in farmlands near five small smelters in Guanzhong were contaminated by Cd,Cu and Pb at different levels and the excessive accumulation of heavy metals in surface soil would lead to increase of pollution risk for the deep layer soil.Thus,the heavy metals pollution in farmlands near small smelters should be concerned. |
| Key words: Guanzhong area heavy metal pollution geostatistics small smelter farmland soil |
