不同土地利用方式对城市土壤质量的影响

通过对兰州市西固区种土地利用类型(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.

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

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、Cd 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.