摘要
为评估雄安新区农田土壤-农作物系统重金属潜在生态风险,分析测试新区小麦籽实和根系土壤中重金属含量及其赋存形态,利用综合污染指数(IPIN)、潜在生态风险指数(RI)、生物富集系数(BFC)和风险评价指数(RAC),采用主成分分析和相关分析等统计方法开展重金属潜在生态风险评估及来源解析.结果表明,新区根系土壤中Cd、Cu、Pb和Zn含量均值显著高于河北省表层土壤背景值.IPI_(N)介于0.2~5.18之间,94.83%的根系土样为安全无污染等级;土壤中Cd单指标潜在生态危害最大,其次为Hg元素,Cr、Ni和Zn潜在生态危害较小;总潜在生态风险以轻微和中等等级为主,占比分别为64.66%和30.17%.根系土壤中Cd生物活性形态组分(离子交换态和水溶态)占比达33.43%,生物有效性相对较高,其他各重金属元素赋存形态均以残渣态为主(残渣态占比>60%).RAC指数由大到小为Cd>Ni>Hg>As>Cu>Cr>Zn>Pb,重金属Cd的RAC均值为22.75%,以中等风险为主,其他各元素RAC均为低风险或无风险.根系土壤重金属主要潜在来源是在地质背景的基础上叠加了人为活动.农作物籽实中重金属迁移、富集能力依次为Zn>Cu>Cd>Hg>As>Ni>Pb>Cr,其中As、Cd、Pb和Zn的生物有效组分对小麦籽实吸收重金属起促进作用,农作物籽实中重金属含量与土壤p H值呈负相关,土壤理化指标(OM和CEC等)双向影响土壤中重金属生物有效态组分比例.
In order to evaluate the potential ecological risk of heavy metals in the soil-crop system in the Xiong'an New District,the heavy metal contents and forms in wheat seed and root soil samples are analyzed,and the comprehensive pollution index(IPIN),potential ecological risk index(RI),bio-enrichment coefficient(BFC),risk assessment code(RAC),principal component analysis,and correlation analysis are used to assess the potential ecological risk of heavy metals and analyze their sources.The results indicate that the average content of Cd,Cu,Pb,and Zn in the root soil is significantly higher than the soil background value in Hebei province.The IPI_(N)ranges from 0.2 to 5.18,94.83%of the soil samples are in the safe and pollution-free grade,and the potential ecological risks of heavy metal are slight and moderate,accounting for 64.66%and 30.17%,respectively.Cd has the greatest potential ecological harm,followed by Hg,Cr,Ni,and Zn.All the heavy metal elements besides Cd in the root soil are dominated by the residual form,which accounts for 60%,and the bioactive form(ion-exchange and water-soluble state)of Cd accounts for 33.43%,indicating relatively high bio-availability.The risk assessment code can be ranked as Cd>Ni>Hg>As>Cu>Cr>Zn>Pb,and the risk of Cd is moderate,while other elements are of low or no risk.The leading potential source of heavy metals is human activity combined with the geological background.The migration and enrichment capability of the wheat seeds is in order from strong to weak of Zn>Cu>Cd>Hg>As>Ni>Pb>Cr,and the biological effective components of As,Cd,Pb,and Zn plays an substantial role in promoting the absorption of heavy metals.The content of heavy metals in the wheat seeds has a negative correlation with the soil pH,and the physical and chemical indices,such as OM and CEC,has bi-directional influence on the biological effective state of the heavy metals.
作者
周亚龙
杨志斌
王乔林
王成文
刘飞
宋云涛
郭志娟
ZHOU Ya-long;YANG Zhi-bin;WANG Qiao-lin;WANG Cheng-wen;LIU Fei;SONG Yuntao;GUO Zhi-juan(Institute of Geophysical&Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang 065000,China;Research Center of Geochemical Survey and Assessment on Land Quality,China Geological Survey,Langfang 065000,China;Key Laboratory of Geochemical Cycling of Carbon and Mercury in the Earth's Critical Zone,Chinese Academy of Geological Sciences,Langfang 065000,China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2021年第4期2003-2015,共13页
Environmental Science
基金
中国地质调查局地调项目(DD20189123)。
关键词
土壤-农作物系统
重金属形态
潜在生态风险
污染来源
雄安新区
soil-crop system
heavy metal forms
potential ecological risk
pollution source
Xiong'an New District
