河南洛阳市不同功能区土壤重金属污染特征及评价

Assessment and Pollution Characteristics of Heavy Metals in Soil of Different Functional Areas in Luoyang

以河南洛阳市居民区、科教区、城市绿地、商业区、城市主干道、工业区和城乡结合处这7个功能区为研究对象,共采集63个样品.分析不同功能区土壤重金属含量,采用单因子污染指数和内梅罗综合污染指数评价重金属污染的程度,Hakanson潜在生态风险指数法评价土壤重金属潜在生态风险,主成分分析重金属污染的成因和来源.结果表明,6种重金属平均含量均超过河南省土壤重金属背景值.不同功能区重金属的单因子污染指数平均污染趋势为Cd>Zn>Pb>Cu>Ni>Cr.内梅罗综合污染指数显示工业区重金属总含量最高,污染最为严重.单个重金属潜在生态危害指数Eir表明,Cd的潜在生态危害指数最高.不同功能区土壤多金属潜在危害危险指数RI依次为工业区(548.87)>主干道(466.06)>商业区(392.81)>居民区(226.27)>科教区(189.76)>绿地(153.72)>城郊(117.45),工业区、主干道和商业区达强生态危害水平,居民区、科教区和绿地达中等生态危害水平,而城乡属轻微生态危害.Cu、Zn、Pb和Cd为人为因子,主要来源于工业废物和交通排放;Cr和Ni为自然源因子,受成土母质的控制.

The residential areas, science and education areas, urban green lands, commercial districts, urban arterial roads, industrial zones and urban and rural junction districts in seven different functional zones of Luoyang City were taken as research subjects, and sixty-three soil samples were gathered. The concentrations of soil heavy metals were measured and their pollution levels were evaluated by single pollution index and Nemerow complex pollution indices. The ecological risks of soil heavy metals were discussed with Hakanson potential ecological risk index （ RI） and their geneses and sources were indicated by the principal component analysis （PCA）. The results showed that the average level of all heavy metals exceeded the background values of Henan Province. The pollution degree of single gene index was in the following order： Cd ﹥ Zn ﹥ Pb ﹥ Cu ﹥ Ni ﹥ Cr. Nemerow complex pollution indices indicated heavy metals had the highest concentration and the heaviest pollution in industrial zones. A single heavy metal potential ecological harm （Eir ） showed Cd had the highest risk index. RI was ranked as industrial zones ﹥ urban arterial roads ﹥ commercial districts ﹥ residential areas ﹥ science and education areas ﹥ urban green lands ﹥ rural junction districts. The heavy metal pollution in industrial zones, urban arterial roads and commercial districts reached strong levels, and the pollution in residential areas, science and education areas, urban green lands reached moderate risk levels, but that in rural junction districts belonged to slight risk level. Cu, Zn, Pb and Cd were called anthropogenic factors and came from industrial wastes and transport emissions, but Cr and Ni were explained as natural factors and their contents depended upon the parent materials of soil.