株洲市云龙示范区土壤重金属Pb、Cd分布特征及污染评价

以株洲市云龙示范区为研究对象,运用单因子指数法和潜在生态危害指数法对其土壤中Pb、Cd的污染状况进行了评价与分析,并运用地累积指数法对评价结果进行了检验。研究结果表明:所有样品中Pb、Cd的实测质量分数范围分别为25.60~102.00,0.03~0.49 mg·kg-1;16个样品Cd的含量超过国家土壤环境质量二级标准,超标率为40%,土壤重金属Cd轻度累积,尤其在0~20 cm土壤层中累积较为严重;综合潜在生态危害指数RI为3.32~51.07,表明该区域综合潜在生态风险处于轻微生态危险水平;地累积指数检验结果表明各地块均存在不同程度的重金属Pb、Cd污染,且污染程度与采样层深度成反比。因此,相关部门应考虑减少农业生产活动对土壤的污染,避免生活垃圾随意堆放形成二次污染等。

An Assessment of Distribution and Pollution Characteristics of Heavy Metals Pb and Cd in the Soil of Yunlong Demonstration Area in Zhuzhou

With Yunlong Demonstration Area of Zhuzhou city as the research object, an evaluation and analysis have been made of the pollution situation of Pb and Cd in soil by adopting the single factor index method and potential ecological hazard index method, followed by a test of the results by using the cumulative index method. The results show that the measured mass fraction of Pb and Cd in all samples were between 25.60~102.00, 0.03~0.49 mg·kg-1, respectively, with the content of Cd in 16 samples exceeding the national secondary standard of soil environmental quality. There is a slight accumulation of heavy metal Cd in the soil, especially within its depth of 0~20 cm. The integrated potential ecological hazard index is within the scope of 3.32~51.07, indicating that the integrated potential ecological risk in this region is at a slightly high level. The cumulative index test results show that there are different degrees of heavy metals Pb and Cd pollution in each region area, with the degree of pollution inversely proportional to the depth of the sampling layer. Therefore, the relevant departments should take into consideration the reduction of the soil pollution caused by agricultural activities, and the prohibition of random staking of the living garbage likely to trigger the secondary pollution.