太湖西南部沉积物重金属的空间分布特征和污染评价

基于GIS地统计模块，对太湖西南部沉积物6种重金属的空间分布特征和污染状况进行了探讨. 结果表明，太湖西南部沉积物重金属含量显著高于太湖沉积物背景值，w(Cd)，w(Cu)，w(Zn)，w(Pb)，w(Ni)和w(As)分别超标4.67，1.27，2.89，2.29，1.94和1.80倍，具有明显的累积效应. 地统计分析表明，太湖西南部沉积物重金属的空间自相关性较弱，说明随机性因素和结构因素对重金属的空间分布有较大的影响. 重金属含量的克里格插值图反映了重金属污染的空间格局，太湖西南区域沉积物已明显受到了重金属Zn，Pb和Cd的污染，西南岸区污染最严重，其次是南岸区，污染最轻的是湖心区. 

Spatial Distribution Characteristics and Pollution Assessment of Heavy Metals in Sediments from the Southwestern Part of Taihu Lake

Spatial distribution characteristics and pollution levels of six heavy metals in the sediments from the southwestern part of Taihu Lake were investigated based on the GIS land statistics module.The results show that heavy metal concentrations in the sediments from the southwestern part of Taihu Lake were significantly higher than the background values.The concentrations of Cd,Cu,Zn,Pb,Ni and As were 4.67,1.27,2.89,2.29,1.94 and 1.80 times higher,respectively,in the southwestern part than the background concentrations.This indicates that there is a clear cumulative effect of these metals.Geostatistical analysis showed that there was little spatial self-correlation between heavy metals in the sediments from the studied area,which indicates that the spatial distribution of the heavy metal concentrations was influenced by random and structural factors.The Kriging interpolation map of heavy metal content reflected the spatial distribution of heavy metal pollution.It showed that the sediments in the southwestern part of Taihu Lake were already seriously contaminated by Zn,Pb and Cd,and also implied that the area of Taihu Lake with the highest heavy metal pollution was the southwestern part,followed by the southern shore and the lake center.