【摘要】 联合野外采样和室内分析,以典型农田土壤为研究对象,分析土壤中重金属Cr、Ni、Cu、Zn、Cd、Pb、As和Hg的含量及污染特征,并采用单因子污染指数法、内梅罗污染指数法及潜在生态危害指数法,对农田土壤进行生态风险评价,同时利用主成分因子分析法,提取出3主因子,分析土壤重金属可能来源。结果表明,研究区农田土壤各重金属含量均高于背景值,表层污染程度高于底层;各重金属单因子污染指数对应污染等级均为清洁,内梅罗污染指数为0.46,污染等级为安全。潜在生态风险评估结果显示,研究区土壤重金属污染的潜在生态风险危害程度为中等,各重金属的潜在生态危害程度依次为Cd>Hg>As>Cu>Pb>Ni>Cr>Zn。主成分因子分析显示,研究区土壤中Hg、As和Cr主要由工业污染源贡献,土壤中Cd、Pb的污染主要来源于不合理的农业生产活动和居民生活,Ni、Zn和Cu与自然成土过程密切相关。综合评价表明,尽管研究区农田土壤目前重金属污染情况较轻,未达到警戒水平,但由于城市化的发展及长期现代化农业耕作活动造成农田土壤重金属的富集,因此,增强农田土壤安全性生产管理、严控土壤污染源与推行标准农业生产是十分必要的。更多还原

【Abstract】 In this study,field investigations and laboratory analyses were combined to analyze the concentrations and pollution levels of Cr,Ni,Cu,Zn,Cd,Pb,As,and Hg in typical agricultural soils in the southern part of Jiangsu Province,China. The ecological risk of heavy metals in farmland soils was assessed using singlefactor pollution,Nemerow pollution,and potential ecological risk indices. Three major factors were further selected after principal component analysis to determine the possible origins of heavy metals in soil. Our results showed that the concentrations of all heavy metals in farmland soils are above the threshold values,and that the pollution level in the topsoil is higher than that in the subsoil. The pollution levels of all heavy metals based on the single-factor pollution index reflected clean levels. The Nemerow pollution index was 0. 46,which indicates low pollution levels. Potential ecological risk assessment indicated moderate risk of soil pollution by heavy metals,and the risk by pollutant species was in the order: Cd > Hg > As > Cu > Pb > Ni > Cr > Zn. Principal component analysis revealed that Hg,As,and Cr pollution of soils is mainly caused by industrial emissions,whereas Cd and Pb pollution is mainly caused by extreme agricultural and residential activities. Ni,Zn,and Cu pollution can be attributed to natural causes. Comprehensive evaluation showed that heavy-metal pollution in the study area has reached alarming levels,and that heavy metals are concentrated in farmland soils that experience urbanization and long-term modern farming activities. Thus,effective farmland soil management is necessary to ensure security production,control soil pollution sources,and implement standard agricultural production.更多还原