洞庭湖南缘农田土壤重金属特征及源解析  

Characteristics and Source Analysis of Heavy Metals in Farmland Soil on the South of Dongting Lake

作　　者：肖凯琦 许安 郭军 李毅 卢永兴 邢新丽[2] 董好刚[1] XIAO Kai-qi;XU An;GUO Jun;LI Yi;LU Yong-xing;XING Xin-li;DONG Hao-gang(Changsha Natural Resources Comprehensive Investigation Center,China Geological Survey,Changsha 410625,China;School of Environmental Studies,China University of Geosciences,Wuhan 430074,China)

机构地区：[1]中国地质调查局长沙自然资源综合调查中心,长沙410625 [2]中国地质大学(武汉)环境学院,武汉430074

出　　处：《环境科学》2023年第2期932-943,共12页Environmental Science

基　　金：自然资源部中国地质调查局项目(DD20200871)。

摘　　要：基于网格布点法于2020年4~8月在洞庭湖南缘农田中采集了1 589件表层土壤样品,采用ICP-MS、 ICP-OES、 HG-AFS和ISE方法测定土壤中As、 Cd、 Pb、 Cu、 Zn、 Ni、 Cr、 Hg元素含量及pH,重点研究了区内土壤重金属含量、潜在生态风险、空间分布特征及其来源解析.结果表明,土壤重金属ω(Zn)、ω(Cr)、ω(Pb)、ω(Cu)、ω(Ni)、ω(As)、ω(Cd)和ω(Hg)平均值依次为:118.18、 82.21、 52.1、 33.76、 32.81、 18.25、 0.42和0.13 mg·kg^(-1).各重金属均处于中、高度变异,土壤以弱酸性为主,pH介于3.96~7.90之间,Hg和Cd存在较高的生态风险.各重金属元素空间分布规律均呈西南高东北低的趋势.采用PMF和PCA方法对8种重金属元素进行来源解析及贡献率计算,PMF结果表明,研究区土壤重金属来源贡献率依次为:农业活动源(36.98%)、自然源(32.94%)、水土交换源(17.05%)和大气干湿沉降源(13.03%),而PCA结果表明研究区土壤重金属主要来源于农业活动源(68.04%)、自然源(31.02%)和大气沉降源(0.94%).两种源解析方法结论趋于一致,即农业活动是研究区内土壤重金属主要来源.通过垂向剖面分析得Cd、 Hg和Pb元素含量呈表层高,深层低的趋势,其人为输入现象明显.研究结果可以为洞庭湖周边农田土壤重金属污染防控对策制定提供科学依据.Based on the grid distribution method,1 589 topsoil samples were collected from farmland on the south side of Dongting Lake from April to August 2020.The content,potential ecological risk,spatial distribution characteristics,and source analysis of heavy metals in the soil were studied.The concentrations and pH of As,Cd,Pb,Cu,Zn,Ni,Cr,and Hg in the soil were determined using ICP-MS,ICP-OES,HG-AFS,and ISE methods.The results showed that the average concentrations of Zn,Cr,Pb,Cu,Ni,As,Cd,and Hg were 118.18,82.21,52.1,33.76,32.81,18.25,0.42,and 0.13 mg·kg^(-1),respectively.All heavy metals had medium or high variability.The soil was mainly weakly acidic with a pH between 3.96 and 7.90.Hg and Cd had high ecological risks.The spatial distribution of heavy metals showed a tendency of being high in the southwest and low in the northeast.The PMF and PCA methods were used to analyze the sources and calculate the contribution rates of the eight types of heavy metals.The PMF results showed that the contribution rates of soil heavy metals in the study area were as follows:agricultural activity sources(36.98%),natural sources(32.94%),water and soil exchange sources(17.05%),and atmospheric dry and wet deposition sources(13.03%).The PCA results showed that the soil heavy metals in the study area mainly came from agricultural activity sources(68.04%),natural sources(31.02%),and atmospheric deposition sources(0.94%).The conclusions of the two source analysis methods tended to be consistent,that is,agricultural activities were the main source of soil heavy metals in the study area.The vertical profile analysis showed that the contents of Cd,Hg,and Pb elements were high in the surface layer and low in the deep layer,and the phenomenon of anthropogenic input was obvious.These results can provide a scientific basis for the formulation of prevention and control countermeasures of farmland soil heavy metal pollution around Dongting Lake.

关 键 词：洞庭湖 农田土壤 重金属 生态风险 来源解析 

分 类 号：X53[环境科学与工程—环境工程]