摘要
近年来,极端天气引发的尾矿库泄露和溃坝事故频发,导致周边农田极易遭受高重金属含量的尾矿砂污染.为进一步探讨富含重金属的尾矿砂进入土壤后砷(As)、锑(Sb)的释放及迁移行为,评估其潜在的污染风险,本研究以安徽省某小型锑金矿区周边农田为例,分析了矿区表层和剖面土壤中砷和锑的含量,并利用污染农田土壤开展了柱淋溶实验.结果表明,研究区污染农田表层土壤中As和Sb的含量分别为(141±11.4)mg·kg-1和(104±5.2)mg·kg-1,分别超过中国土壤背景值12倍和85倍,也远高于对照田表层土壤,达到重度污染水平.尽管具有相似的地球化学性质,但As和Sb在土壤垂向迁移方面表现出不同的特性.土壤中的Sb主要分布于表层,其含量随剖面深度增加逐渐降低;而土壤As含量除表层较高外(113 mg·kg-1),在60 cm深度出现一个极大值(114 mg·kg-1).这表明表层污染土壤中的As和Sb会逐渐向下迁移,并且As的迁移能力高于Sb.在不同pH和不同浓度磷溶液淋滤下,As的释放强度均明显大于Sb,不同pH溶液淋滤条件下As的最大释放浓度达到1151μg·L-1,Sb的最大释放浓度只有10μg·L-1.不同浓度磷溶液淋滤条件下As和Sb的最大淋出浓度分别为1277μg·L-1和170μg·L-1.磷肥的大量施加可以促进尾矿砂污染土壤中As、Sb的释放,增大其潜在生态风险.
Recent years,tailings pond dam leakage and break accidents arising from extreme weather happened frequently,causing serious pollution to the surrounding farmland by tailings with high content of heavy metals.This study was to investigate the release and transport behavior of arsenic and antimony after the tailings entered the soil,and assess its potential pollution risks furtherly.The contents of arsenic and antimony in the surface and profile soil of a small antimony gold mining area in Anhui province were analyzed.Column leaching experiments were also carried out using the contaminated soil.The farmland soil in the study area was seriously polluted by arsenic and antimony.The contents of arsenic and antimony in the surface soil of the contaminated farmland were(141±11.4)mg·kg-1and(104±5.2)mg·kg-1,respectively,which were 12 and 85 times higher than their background value in Chinese soil,and also significantly higher than the control soil.The soil pollution reached the level of heavy pollution.Despite similar geochemical properties,the vertical migration of As and Sb showed different characteristics.Antimony in soil was mainly distributed in the surface layer,and its content decreased gradually with the increase of depth.In addition to high content in surface layer(113 mg·kg-1),arsenic content showed a maximum value at the depth of 60 cm(114 mg·kg-1).This indicated that arsenic and antimony in surface contaminated soils would gradually migrate downward,and the migration capacity of arsenic was higher than that of antimony.Under leaching conditions of different pH and phosphorus concentrations,the release intensity of arsenic was significantly greater than that of antimony.The maximum release concentrations of arsenic and antimony were 1151μg·L-1 and 10μg·L-1 under different pH conditions.The maximum release concentrations of arsenic and antimony were 1277μg·L-1 and 170μg·L-1,respectively,when leaching with different phosphorus solutions.The application of phosphate fertilizer could promote the release of arsenic and antimony in the soil contaminated by tailings,which increased a potential ecological risk.
作者
蔡永兵
邵俐
范行军
李飞跃
孟凡德
张华
CAI Yongbing;SHAO Li;FAN Xingjun;LI Feiyue;MENG Fande;ZHANG Hua(College of Resource and Environment,Anhui Science and Technology University,Fengyang,233100,China;Anhui Province Key Laboratory of Biochar and Cropland Pollution Prevention,Bengbu,233400,China;Key Laboratory of Coastal Zone Environmental Processes,Yantai Institute of Coastal Zone Research,Chinese Academy of Sciences,Yantai,264000,China)
出处
《环境化学》
CAS
CSCD
北大核心
2020年第9期2479-2489,共11页
Environmental Chemistry
基金
安徽省自然科学基金(1808085QD110,1908085QD166)
国家自然科学基金(41907137,21607002)
安徽省高校自然科学研究项目(KJ2020A0051)
大学生创新创业训练计划项目(S201910879071)资助~~
关键词
矿区
农田土壤
AS
SB
释放迁移
mining area
farmland soil
arsenic
antimony
release and transport
作者简介
通讯联系人:张华,E-mail:hzhang@yic.ac.cn
