新乡市近郊农田土壤重金属的生态风险评价

Potential Ecological Risk Assessment of Heavy Metals in the Suburban Farmland Soil from Xinxiang City

基于对新乡市近郊农田土壤的采样分析,利用潜在生态危害指数法及因子分析法,分析研究了土壤中重金属的潜在生态风险程度,内在关联性及其可能的污染来源.结果表明:土壤中重金属Cr与Cu的含量在国家土壤二级标准以内,而Cd,Ni与Zn含量明显超标;土壤重金属可能引起严重的综合生态风险,其中Cd,Ni的潜在生态风险等级分别隶属于极强生态风险级别,很强生态风险级别,Zn,Cr,Cu则隶属于轻微生态污染级别;土壤中Ni与Cd,Cu与Cr有显著的正相关性(p<0.01),其他重金属元素间无明显的相关性;Ni与Cd作为第一主成分被认为与电池废液灌溉有密切的关系,Cu与Cr作为第二主成分被认为主要与岩石或矿物的自然风化或侵蚀有关.

Contents and potential ecological risk of heavy metals in the Suburban Farmland soil of Xinxiang city have been researched based on the index of Hakanson potential ecological risk and factor analysis.The results show that the gross concentrations of Cr,Cu are lower than the nation standard,by contrast,the gross concentrations of Cd,Ni,Zn exceed the nation standard obviously.The degree of potential ecological risks indicated that Cd and Ni reached the higher degree of potential ecological risk,stronger ecological risk degree and strongest ecological risk degree respectively.Contrastively,ecological risk degree of Zn,Cr,Cu are all at the faint ecological risk degree.Factor analysis indicates the significant correlations exist among Cd and Ni,Cu and Cr,however,other heavy metals have no significant correlation.In consideration of the economic characters of Xinxiang city,Ni and Cd,as the first principal component,are in deep relation with waste water irrigation of battery industry.Cu and Cr,as the second principal component,are considered as the result from the natural rock weathering and soil erosion.