山东省典型工业城市土壤重金属来源、空间分布及潜在生态风险评价

Assessment of Sources,Spatial Distribution and Ecological Risk of Heavy Metals in Soils in a Typical Industry-based City of Shandong Province,Eastern China

选取山东省典型工业城市——莱芜市钢城区为研究区域,系统采集了106个表层土壤样品,测定了As、Cd、Co、Cr、Cu、Hg、Ni、Pb和Zn等9种重金属的含量,分别利用多元统计和地统计方法分析了重金属的来源和空间分布特征,最后对土壤重金属的潜在生态风险进行了评价.结果表明:1研究区9种重金属元素的平均含量均超过了山东省土壤背景值,其中Cd、Hg、Pb和Zn的平均值分别是背景值的2.42、4.69、1.74和1.54倍,在表层土壤中存在明显的富集.2Cd、Pb和Zn主要来源于工业"三废"、交通排放以及农药化肥的施用;Co、Cr和Ni为自然源因子,受到成土母质的控制;As和Hg来源于煤炭燃烧和钢铁冶炼,Cu受自然与人为因素共同影响.3研究区总体上处于中等与高生态风险的临界水平,其中Hg为高生态风险水平,Cd为中等生态风险水平,其他元素则均为低生态风险.

A total of 106 samples were collected from surface soils in Gangcheng District,Laiwu city( a Typical industry-based city of Shandong Province,Eastern China),and the contents of 9 heavy metals including As,Cd,Co,Cr,Cu,Hg,Ni,Pb and Zn were determined. Multivariate analysis and geostatistics were applied to examine the sources and spatial distributions of heavy metals in soils; and the assessment on ecological risk of heavy metals was carried out using Hakanson's method. The average concentrations of 9heavy metals were higher than the background values of Shandong Province; in particular,the mean contents of Cd,Hg,Pb and Zn were 2. 42,4. 69,1. 74 and 1. 54 times of their respective background values,which indicated there were obvious accumulations of these heavy metals in surface soils. The results from multivariate analysis suggested that all the 9 heavy metals could be classified as 3Principal Components( PCs). Cd,Pb and Zn,having high loads in PC1,were dominated by industrial,agricultural and traffic sources. PC2 including Co,Cr and Ni came from natural sources,and were controlled by parent materials. As and Hg with high loads in PC3,were originated from coal combustion and smelting. Cu had some loads on different PCs,and was affected by both natural and human sources. Assessment on ecological risk indicated that the study area suffered from a critical level between high and moderate risks. Hg was at the high ecological risk level,and Cd was at the moderate ecological risk level,while other metals had low ecological risk level.