天津农田重金属污染特征分析及降雨沥浸影响  

Characteristics of Heavy Metals Pollution of Farmland and the Leaching Effect of Rainfall in Tianjin

作　　者：许萌萌 刘爱风 师荣光[2] 蓝靖[3] 田永 赵宗山 

机构地区：[1]中国科学院青岛生物能源与过程研究所,生物基材料重点实验室,青岛266101 [2]农业部环境保护科研监测所,天津300191 [3]青岛农业大学化学与药学院,青岛266109

出　　处：《环境科学》2018年第3期1095-1101,共7页Environmental Science

基　　金：国家自然科学基金项目(21477138); 中国博士后科学基金项目(2016M602210)

摘　　要：降雨过程对农田土壤重金属的淋洗效应是影响重金属在土壤中迁移与转化的重要过程.本文不仅考察了天津市污灌区农田表层土壤中7种重金属的含量水平和空间分布特征,还结合之前发表的地表径流中重金属含量数据,探讨了自然界降雨对土壤重金属的淋洗作用.多元分析结果表明,农田土壤中各种金属含量差异较大.其中Zn含量最高[(106.61±56.24)mg·kg-1],Cd含量最低[(0.31±0.31)mg·kg-1],但Cd含量4倍于当地土壤背景值(0.090 mg·kg-1).7种土壤重金属综合污染指数排序为Cd>Cu>Ni>Zn>As≈Cr>Pb.土壤Cd、Cu、Ni和Zn分别属于中度污染、轻度污染和警戒水平,而As、Cr和Pb均属于安全等级.多元分析结果还表明,研究区内土壤Cd主要来源于人为活动,包括工业及机动车排放、污水灌溉等,Zn、Cu、Cr、Ni和Pb受人为源和自然源的综合影响,而As则主要为自然源.降雨过程对土壤中7种重金属的浸出情况排序为Cd>As>Cu≈Pb>Ni>Cr≈Zn.综上,天津市土壤Cd污染较为突出,需要进行重点监测及专项治理.The leaching effect of the rainfall process for removing heavy metals from farmland soils is a critical physical process. To study the leaching effect of the rainfall process on heavy metals in soil,the pollution characteristics of seven heavy metals in farmland soil have been investigated in the suburban Tianjin region by combining the current data with previously reported runoff data in the same region. There is a large difference for these tested heavy metals in soils,with Zn having the highest concentration at 106. 61 ± 56. 24 mg·kg^-1 and Cd having the lowest concentration at 0. 31 ± 0. 31 mg·kg^-1. Compared with the background value in Tianjin,only the content of Cd is at higher levels（a four-fold increase）. The results from a single factor pollution index and comprehensive pollution index analysis indicate that the comprehensive pollution index ranking is Cd〉 Cu 〉Ni 〉Zn〉 As≈Cr 〉Pb. Cd,Cu,Ni,and Zn are in the moderate pollution,mild pollution,and alert level categories,respectively. Except for As,the results from a correlation analysis,the principal component analysis（PCA）,and the cluster analysis indicate the possible similar origins of Cr,Ni,Cu,Zn,Cd,and Pb. The multivariate statistical analysis indicates that Cd is mainly derived from human activities,Zn,Cu,Cr,Ni,and Pb are affected by anthropogenic and natural sources,and As is mainly influenced by natural conditions. By comparing the ratios of individual heavy metals to Cr in soils and runoffs,the leaching behaviors have been studied,with the leaching capacity ranked as Cd As 〉Cu≈Pb Ni Cr≈Zn. In summary,Cd pollution in soil is more prominent than pollution from other metals and should receive attention.

关 键 词：重金属 农田土壤 降雨径流 天津市郊 多元分析 

分 类 号：X52[环境科学与工程—环境工程] X53