摘要
黑色岩系风化是我国西南地区土壤重金属元素环境背景值高的重要原因之一,目前关于黑色岩系高地质背景区农田土壤-农作物系统重金属的富集特征及影响因素的认识仍存在不足。本研究选择重庆市城口县典型黑色岩系高地质背景区为研究区,研究了土壤-玉米系统中的重金属元素总量、生物有效性与迁移富集过程及影响因素。结果表明,研究区土壤中重金属元素的富集程度为Cd>Zn>Cu>Ni>Cr>Pb,Cd、Zn、Cu和Ni含量均高于我国土壤背景值,Cd的平均含量达5.11 mg·kg^(-1)。研究区土壤Cd的污染程度最高(Igeo为1.35~7.04),82%的土壤样品达到了重度污染水平,潜在生态风险最高(Er平均值为1534),为该区域的特征污染元素。土壤样品有效态Cd含量为0.001~1.51 mg·kg^(-1),平均提取率为6.14%,且在酸性条件下随土壤pH增加显著降低,在近中性条件下对pH变化的响应不明显。玉米籽粒对重金属的富集程度低,其中Cd的干重含量为0.001~1.36 mg·kg^(-1),超标率为14%,基本处于安全水平。玉米籽粒中重金属含量与土壤重金属总量无明显关系,与有效态的关系在不同pH条件下存在差异。
The weathering of black shale is a vital contributor to the high background values of heavy metals(HMs)in soils in Southwest China.However,the accumulation characteristics and controlling factors of HMs in soil-crop systems are not well understood.We investigated the bulk contents and bioavailability of HMs and their transfer pattern from soil to maize in a typical black shale area with high geochemical background in Chengkou of Chongqing.The results showed that the accumulation factor of HMs in soils from the study area followed an order of Cd>Zn>Cu>Ni>Cr>Pb,with Cd,Zn,Cu and Ni exceeding the background value.Cd was the main HM contaminant in the study area.Average Cd content in bulk soils was 5.11 mg·kg^(-1).The soils were seriously polluted by Cd,with Igeoranging from 1.35 to 7.04.82%of soil samples were classified as heavy contamination based on Igeo.The Cd in these soils posted high ecological risk,with an average Erof 1534.The contents of bioavailable Cd in the soils ranged from 0.001 to 1.51 mg·kg^(-1),with an average extractability of 6.14%.Extractability of Cd decreased with increasing soil p H in acidic soils,and slightly changed with p H in near-neutral soils.The accumulation of HMs in maize was low,with the total Cd contents ranging from 0.001 to 1.36 mg·kg^(-1).14%of maize samples exceeded the safety threshold of cereal.There was no relationship between the contents of HMs in maize grains and their bulk contents in soils.The relationship between Cd content in maize grains and soil available Cd content depended on soil p H conditions.
作者
陈梓杰
肖唐付
刘意章
邢丹
杨军
朱正杰
宁增平
CHEN Zi-jie;XIAO Tang-fu;LIU Yi-zhang;XING Dan;YANG Jun;ZHU Zheng-jie;NING Zeng-ping(School of Environmental Science and Engineering,Guangzhou University,Guangzhou 510006,China;State Key Laboratory of Environmental Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China;Institute of Pepper,Guizhou Academy of Agricultural Science,Guiyang 550006,China;College of Agriculture and Food Engineering,Baise University,Baise 533000,Guangxi,China)
出处
《生态学杂志》
CAS
CSCD
北大核心
2021年第8期2315-2323,共9页
Chinese Journal of Ecology
基金
国家重点研发计划项目(2017YFD0800302)
国家自然科学基金(41773142)
贵州省科学技术基金资助项目(黔科合基础[2017]1195
[2018]1177)
中国科学院青年创新促进会(2021399)
贵州省高层次留学人才择优资助项目[(2020)10号]资助。
关键词
黑色岩系
镉污染
土壤
农作物
生物有效性
black shale
cadmium pollution
soil
food crop
bioavailability
