不同土地利用方式对城市土壤质量的影响

The effects of different land-use types on quality of urban soils

通过对兰州市西固区5种土地利用类型(工业园区、道路两侧、农业、居民区和公园)320个土壤样品的测试,研究了不同土地利用方式对城市土壤理化性状和Pb、Zn、Cd、Cu、Hg元素积累的影响。在5种类型土壤中,工业园区土壤的pH值最低而电导率最高,道路两侧土壤有机碳含量显著高于居民区、公园和农业土壤;Pb、Zn、Cu、Cd和Hg的含量在5种类型土壤中存在显著差异,并明显高于兰州市土壤背景值;计算得到的工业园区、道路两侧、农业、居民区和公园土壤的内梅罗综合污染指数分别为4.9、3.7、4.0、2.4和2.2。结果表明,不同土地利用方式对城市土壤质量的影响不同,工业活动的影响最大,交通污染次之,再依次为农业活动及居民生活。

320 topsoil samples （0 - 10cm） were collected from five different land-use sites （i.e. industrial areas,, roadsides, agricultural areas, residential areas and parks） in Xigu District of Lanzhou city, northwest China. Physical-chemical properties and contents of Pb, Zn, Cu, C d and Hg in these samples were analyzed to examine the effects of the different land-use types on quality of urban soils. The results showed that （1） soil samples from the industrial areas had the lowest pH but the highest electric conductivity among the five sites; （2） the contents of organic carbon in the roadside soil samples were significantly higher than those in the agricultural, residential and park soils; （3） the contents of Pb, Zn, Cu, Cd and Hg varied significantly between the five sites but were consistently higher than the background values of local soils： and （4） the calculated Nemerow integrated pollution indices were 4.9, 3.7, 4.0, 2.4 and 2.2 for the industrial areas, roadsides, agricultural areas, residential areas and parks, respectively. This study suggests the differential effects of the five different land-use types on the physical-chemical properties and accumulation of heavy metals in urban soils, with the strongest influence by industrial activities, followed by ＇ traffic activities, agricultural activities and inhabitant living activities.