西安市南、北郊土壤重金属含量及对小青菜影响对比

目的]为西安市郊菜园土壤环境评价和治理污灌区重金属污染和减少蔬菜重金属含量提供理论依据。方法]以西安市南、北郊露地菜园土壤及蔬菜为研究对象,采用原子吸收分光光度法分别对样品中的重金属Pb、Cd、Cu、Zn含量进行测定,研究分析土壤的污染状况和蔬菜的质量。结果]北郊土壤中Pb、Cd、Cu、Zn平均含量分别为南郊菜园土壤的2.3、4.1、1.7、2.9倍;重金属元素在北郊菜园土壤中发生了明显的累积,不同元素在土壤中累积强度明显不同,其顺序为Cd〉Zn〉Pb〉Cu;北郊土壤中重金属Cd严重污染、Zn三级轻度污染,南郊土壤Cd三级轻度污染;北郊菜园小青菜中富集的重金属Cd超出无公害蔬菜国家限量标准2.0倍,小青菜已受重金属Cd严重污染。结论]根据不同蔬菜品种对重金属吸收能力的不同,在重金属污染区选择适当的蔬菜品种进行科学种植。

Study on the Content of Heavy Metal in the Soil of Southern and Northern Suburb of Xian City and Comparison of Them on Brassica chinensis Growth

Objective] The theoretic basis of the environmental evaluation and management of the vegetable land contaminated by heavy metal in suburb of Xi'an City and the measure for the reduction of the content of the heavy metal in vegetable was provided through the analysis.Method] The content of Pb,Cd,Cu and Zn in the vegetable grown in the southern and northern suburb of Xi'an city and its planting soil in was tested with atomic absorption spectrophotometry and then the current situation of the contaminated soil and the vegetable quality was analyzed.Results] The content of Pb,Cd,Cu and Zn in the experimental soil of northern suburb was 2.3,4.1,1.7,2.9 times more than those in the southern suburb,respectively;the accumulation of heavy metals in soil of the northern suburb is significant and the obvious accumulation of heavy metal in soil of northern suburb appeared.The accumulation of heavy metal in soil are different in various element of heavy metal,which order was Cd > Zn > Pb >Cu.In northern region,the contamination of Cd in soil was the heaviest and the contamination of Zn in soil was light at the 3rd level;and also,the contamination of Cd in soil of southern region was light at the 3rd level.The content of Cd in the Brassica Chinensis from the northern part was 2.0 times more than that of State Limited Standard of Non-environmental Polluted Vegetable,so the contamination of Cd to Brassica Chinensis was very serious.Conclusion] The scientific planting was the key of the control and reduction of the heavy metals to vegetable in contaminated region based on the selection of different species of vegetables.