苏南经济快速发展区土壤重金属含量的空间变化研究

文章以经济快速发展的江苏省昆山市为研究区,研究了该区土壤重金属含量的空间变化。结果表明:土壤重金属平均污染指数大于1的有镍、锌、汞,其中汞的污染指数最大,是主要污染物。土壤重金属复合污染严重,综合污染指数达1.52,变异系数以汞、镉、铅、铜较大。不同功能区土壤重金属元素全量综合污染指数按以下顺序递降:化工区(1.84)>养殖区(1.54)>大棚菜地区(1.22)>印染造纸区(0.99)。不同地貌区土壤重金属元素全量综合污染指数按以下顺序递降:中部平原区(1.71)>北部洼区(1.57)>南部湖荡区(0.99)。测定的剖面样品中各重金属元素在剖面上一般都有表聚、亚表聚特征,总体上是上层含量高于下层,增加了环境风险。

Spatial Variation of Content of Soil Heavy Metals in Region with High Economy Development of South Jiangsu Province

Spatial variation of the content of soil heavy metals in Kunshan City of Jiangsu Province was studied. The results show that the average contamination index of Ni, Zn and Hg is more than 1, and that of Hg is the biggest one, Hg is the main contamination; compound contamination of soil heavy metals is severe, integrated contamination index gets to 1.52; variance coefficients of Hg, Cd, Pb, Cu are bigger than that of others. Integrated contamination index of total amount of soil heavy metals in different function areas decreases as follow: area of chemical factory (1.84)> area of aquiculture and poultry (1.54)> area of vegetable plot (1.08) > area of printing, dyeing, and paper-making (0.99). Integrated contamination index of total amount of soil heavy metals in different physiognomy areas decreases as follow: plain area in middle (1.71)> low area in north (1.57)> lake area in south (0.99). Heavy metals have the character of top gathering and sub-top gathering in soil profiles, and the content of heave metals in top layer is higher in general, thus leads to the increasing of risk to environment.