三峡库区二叠系孤峰组硅质岩分布区土壤-农作物重金属元素地球化学特征  

Accumulation of Heavy Metals in Agricultural Soils and Crops in the Permian Gufeng Formation Siliceous Rock Distribution Region in Three Gorges Reservoir Area

作　　者：双燕 李航 杨振鸿 易宗旺 李海 SHUANG Yan;LI Hang;YANG Zhenhong;YI Zongwang;LI Hai(Green Intelligence Environmental School,Yangtze Normal University;Chongqing Institute of Geology and Mineral Resources;Chongqing Key Laboratory of Water Environment Evolution and Pollution Control in Three Gorges Reservoir,Chongqing Three Gorges University;Chongqing Bureau of geology and Minerals Exploration;No.107 Geology Team,Chongqing Bureau of geology and Minerals Exploration)

机构地区：[1]长江师范学院绿色智慧环境学院 [2]重庆地质矿产研究院 [3]重庆三峡学院三峡库区水环境演变与污染防治重庆市重点实验室 [4]重庆市地质矿产勘查开发局 [5]重庆市地质矿产勘查开发局107地质队

出　　处：《地球与环境》2024年第2期188-198,共11页Earth and Environment

基　　金：重庆市科委自然科学基金计划(cstc2019jcyj-msxmX0201);重庆市高校创新研究群体(CXQT19030)。

摘　　要：三峡库区二叠系孤峰组硅质岩分布区土壤、农作物具有重金属富集特征,本文选择三峡库区典型孤峰组分布区为研究对象,研究了土壤-农作物系统中重金属元素含量、赋存形态与迁移富集规律及影响因素。结果表明,研究区土壤重金属富集程度为Cd>Mo>Hg>Cr>Ni>Cu>Zn>As>Pb,含量均高于我国土壤背景值。土壤Cd平均含量12.98 mg/kg,超标率达100%,单因子污染指数和地累积指数均显示为重度污染;平均生态风险因子(Er)为4929,表现为极高生态风险,因而是研究区重点关注的特征环境元素。Cd的赋存形态主要为可交换态、残渣态和可还原态,生物有效态含量与土壤pH值以及耕种程度密切相关。农作物中Cd的含量变化为:莴笋茎>莴笋叶>胡豆>卷心菜>土豆>油菜籽,Cd、Cr等元素超标现象较为严重。重金属元素在土壤-农作物体系的迁移能力变化顺序为:Cd>Zn>Cu>Ni>Cr>Pb。不同植物类型对重金属元素的富集能力差异显著,莴笋茎和莴笋叶对重金属元素富集能力最强,其中Cd的生物富集系数最高。元素赋存形态、土壤pH值以及农作物类型可能是影响重金属元素在土壤-农作物系统中迁移转化的重要因素。The agricultural soils and crops in the siliceous rock distribution area of the Permian Gufeng Formation in the Three Gorges Reservoir Area are characterized by enrichment of heavy metals.This paper studied concentration of heavy metals,the chemical speciation of Cd in the agricultural soils and crops in the typical Gufeng Formation distribution region in the Three Gorges Reservoir Area,to reveal the environmental impacts on the migration and enrichment process of heavy metals in soils-crops system.The results showed that the enrichment degree of heavy metals in the soil of the study area was Cd>Mo>Hg>Cr>Ni>Cu>Zn>As>Pb,with all elements higher than the background values of soil in China.The pollution degree of Cd in soil of the study area is the highest,with an average concentration of 12.98 mg/kg,and all the samples exceeded the official standard concentration.Both the single factor pollution index and geoaccumulation index of Cd present a serious pollution grade.The average ecological risk factor(E_r)was 4929,indicating a very high ecological risk.Cd was mainly occurred as exchangeable,residual,and reducible state.The content of Cd in crops from the study area followed an order of lettuce stem>lettuce leaf>bean>cabbage>potato>rape seeds,with Cd,Cr and other elements exceeding the safety threshold of agriculture products.The transport capacity of heavy metals varies significantly in different plant types.Lettuce stems and leaves are prone to enriched in Cd.The occurrence forms of elements,soil pH values and crop types are positively correlated with the migration of heavy metals in crops and crops system.

关 键 词：三峡库区 土壤 重金属元素 农作物 

分 类 号：P595[天文地球—地球化学]