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 totaI of 106 sampIes were coIIected from surface soiIs in Gangcheng District, Laiwu city ( a TypicaI industry_based city of Shandong Province, Eastern China) , and the contents of 9 heavy metaIs incIuding As, Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn were determined. MuItivariate anaIysis and geostatistics were appIied to eXamine the sources and spatiaI distributions of heavy metaIs in soiIs;and the assessment on ecoIogicaI risk of heavy metaIs was carried out using Hakanson’s method. The average concentrations of 9 heavy metaIs were higher than the background vaIues of Shandong Province; in particuIar, the mean contents of Cd, Hg, Pb and Zn were 2. 42, 4. 69, 1. 74 and 1. 54 times of their respective background vaIues, which indicated there were obvious accumuIations of these heavy metaIs in surface soiIs. The resuIts from muItivariate anaIysis suggested that aII the 9 heavy metaIs couId be cIassified as 3 PrincipaI Components (PCs). Cd, Pb and Zn, having high Ioads in PC1, were dominated by industriaI, agricuIturaI and traffic sources. PC2 incIuding Co, Cr and Ni came from naturaI sources, and were controIIed by parent materiaIs. As and Hg with high Ioads in PC3, were originated from coaI combustion and smeIting. Cu had some Ioads on different PCs, and was affected by both naturaI and human sources. Assessment on ecoIogicaI risk indicated that the study area suffered from a criticaI IeveI between high and moderate risks. Hg was at the high ecoIogicaI risk IeveI, and Cd was at the moderate ecoIogicaI risk IeveI, whiIe other metaIs had Iow ecoIogicaI risk IeveI.