上海市湖泊沉积物重金属的空间分布

Spatial distribution of heavy metals in lake surface sediments in Shanghai

上海快速城市化发展导致公园湖泊表层沉积物中重金属Cd、Hg、Cu、Pb和Zn含量出现富集,其最大值已超出各自土壤背景值3.8～5.8倍.这5种重金属的污染热点主要出现在核心城区的人口和交通密集区、浦西沿江老工业区以及郊区新兴工业区附近.基于土地利用类型、交通变量、人口密度和工业点源等预测变量构建了高精度的土地利用回归模型,推测沉积物中Cd和Pb浓度分别主要受路网密度和商业用地影响,Hg和Cu主要受商业用地和工业点源数影响,Zn主要受居住用地和工业点源数影响.

Rapid urbanization development has caused high accumulation of heavy metals(Cd,Hg,Cu,Pb,and Zn)in urban lake surface sediments from city parks in Shanghai.Compared to their soil background values,the maximum levels of five metals in lake sediments were higher 3.8~5.8times.The pollution hotspots existed in the urban areas with larger population density and traffic volume,old industrial areas in the west side of Huangpu River,and emerging industrial areas in the suburb.Land use regression(LUR)models were successfully developed to evaluate spatial variations of heavy metal accumulations in urban lake sediments based on four predictor variables such as land use types,traffic variables,population density,and industrial sources.LUR models deduced that the major control factors for Cd and Pb levels in lake sediments were roadway density and commercial land area,respectively,commercial land area and number of industrial point sources for Hg and Cu,residential land area and number of industrial point sources for Zn.