城市不同功能区土壤重金属特性分析——以南京市玄武区为例

Characteristics of Heavy Metals in the Soil of Different Urban Areas-A Case Study of Xuanwu District in Nanjing

重金属污染以其具有难降解、易积累、毒性大和具有隐蔽性、长期性和不可逆性等特点已成为全球各国共同面对的棘手问题之一。在单因子指数法评价值的基础上,以国家土壤环境质量标准为背景值,采用污染负荷指数法和内梅罗指数法对南京市玄武区不同功能区土壤中重金属铬(Cr)、镉(Cd)、镍(Ni)、铅(Pb)、锌(Zn)、铜(Cu)的综合污染程度进行分析。结果表明,Cd在4个功能区的土壤中均属于重度污染;Ni和Zn在锁金村居民区和藤子村工业区土壤中属于轻度污染;各功能区土壤重金属综合污染程度由大到小依次为:藤子村工业区>玄武湖公园休闲区>锁金村居民区>中央门交通繁忙区,且藤子村工业区土壤重金属的综合污染水平达到重度污染。本次研究结果为城市不同功能区土壤重金属污染现状水平提供了参考。

Heavy metal pollution in soils has become an environmental issue for countries around the world due to difficult degradation, easy to accumulate, severe toxicity levels, the extended lifetime in the soils, hard to identify, and irreversible characteristics. Using the guidelines established by the State Soil Environment Quality Standard and on the base of the value of single factor index method, this study adopted the Nemerow index and the pollution load index models to evaluate the overall heavy metal pollution level （Cr, Cd, Ni, Pb, Zn, and Cu）found in various urban areas of the Xuanwu district in Nanjing. The locations tested include Tengzi village industrial area, Xuanwu park recreational area, Suojin village residential area, and Zhongyangmen traffic area. The results indicated that the heavy metal cadmium had caused severe pollution in the soil of all four urban areas ; nickel and zinc caused light pollution in the soil for SuoJin residential and Tengzi village industrial zone; chromium, lead, and copper were found to be in the safe range in all four areas. The overall degree of heavy metal pollution in the soil of the four urban areas are as follows ： Tengzi village industrial 〉 Xuanwu park recreational 〉 Suojin village residential 〉 Zhongyangmen traffic. Only the heavy metal pollution level found in the soils of the Tengzi village industrial area were considered to be serious. The results have provided certain reference for the level of heavy metal pollution in the city.