地下水中痕量汞的形态分布与迁移机制  

Speciation and mobilization of ultra-trace Hg(II)in groundwater

作　　者：皮坤福 王焰新 LIU Juewen 杨雅楠 PHILIPPE Van Cappellen PI Kunfu;WANG Yanxin;LIU Juewen;YANG Ya’nan;PHILIPPE Van Cappellen(School of Environmental Studies&MOE Key Laboratory of Groundwater Quality and Health,China University of Geosciences,Wuhan,Hubei 430074,China;Ecohydrology Research Group,Department of Earth and Environmental Sciences,University of Waterloo,Waterloo,Ontario N2L3G1,Canada;Department of Chemistry&Waterloo Institute for Nanotechnology,University of Waterloo,Waterloo,Ontario N2L3G1,Canada)

机构地区：[1]中国地质大学(武汉)环境学院/地下水质与健康教育部重点实验室,湖北武汉430074 [2]滑铁卢大学地球与环境科学系生态水文学研究组,安大略省滑铁卢N2L3G1 [3]滑铁卢大学化学系/纳米技术研究所,安大略省滑铁卢N2L3G1

出　　处：《水文地质工程地质》2025年第2期1-13,I0001-I0004,共17页Hydrogeology & Engineering Geology

基　　金：国家重点研发计划项目(2023YFC3708001);111计划(B18049);中央高校基本科研业务费(CUG230614);加拿大自然科学与工程研究委员会战略合作伙伴项目(STPGP 507070)。

摘　　要：精确测定地下水中不同形态汞(Hg)的浓度变化,对于深入解析汞的迁移转化机制及其对水生态安全构成的潜在风险具有重要意义。然而,这一基础性研究工作目前面临挑战,瓶颈问题在于缺乏一种兼具高灵敏度、高可靠性且适宜现场快速部署的检测技术,以实现对地下水中超痕量Hg(II)的精准监测。鉴于此,文章介绍了基于脱氧核糖核酸(DNA)传感材料的新型检测手段,并深入探究了两种生物传感方法的可行性及优劣:其一是利用DNA功能化水凝胶直接检测地下水中的Hg(II);其二则是通过结合薄膜扩散梯度技术(DGT)与DNA传感元件,构建DNA-DGT传感器,实现Hg(II)的即时采样与检测。通过对来自加拿大格兰德河流域具有多种水文地球化学特征的地下水进行测试,发现DNA功能化水凝胶能够快速检测溶解态Hg(II),但不适用于低浓度Hg(II)(<1.60μg/L),而DNA-DGT传感器可以根据测试时长捕获不同浓度的超痕量Hg(II)形态。进一步结合DNA-DGT传感器检测和水文地球化学计算对地下水中Hg(II)形态进行量化分析,发现温度、pH值、Cl^(-)和溶解性有机质(dissolved organic matter,DOM)对痕量Hg(II)的形态分布、扩散效率及迁移能力产生显著影响。结合水文地球化学模拟分析,DNA-DGT测量结果揭示了Hg(II)的迁移转化过程与地下水中硫的氧化还原循环存在密切关联。研究强调了运用高灵敏度、便于现场部署的生物传感方法监测低浓度Hg(II),对于认识地下水中汞的迁移转化规律及其对安全供水构成的潜在威胁具有重要意义。Accurate quantification of various mercury(Hg)species dynamics in groundwater is critical for understanding Hg mobilization,fate,and consequent impacts on water ecological security.This foundational work,however,faces challenges due to the lack of highly sensitive,reliable,and field-deployable detection technologies that can determine and monitor ultra-trace Hg(II)in groundwater.Here,this research presents and assesses two types of biosensing methods for dissolved Hg(II)based on a deoxyribonucleic acid(DNA)sensing material:the DNA-functionalized hydrogel for direct Hg(II)detection in groundwater and the DNA-DGT sensor for simultaneous sampling and detection with the diffusive gradients in thin films technique(DGT).Applying tests to hydrogeochemically diverse groundwaters from the Grand River Watershed,Canada,the results indicate that the DNA-functionalized hydrogel is able to quickly detect dissolved Hg(II)but inapplicable to low Hg(II)concentrations(<1.60μg/L),whereas the DNA-DGT sensor can capture variably ultra-trace Hg(II)species depending on the deployment time.Quantification of Hg(II)species in groundwater via joint DNA-DGT sensing and hydrogeochemical calculation indicates that temperature,pH,Cl^(-),and dissolved organic matter significantly affected partitioning of trace Hg(II)between various mobile species,diffusion efficiency,and thus its mobility.Combined with hydrogeochemical modeling,the DNA-DGT measurements reveal that mobilization and transformation of Hg(II)are linked to redox cycling of sulfur in groundwater.This study therefore highlights that monitoring of low-level Hg(II)with ultra-sensitive,field-deployable biosensing methods is of significance to understanding mobility and fate of Hg in groundwater and its threat to safe drinking water supply.

关 键 词：汞 生物纳米传感 地下水污染 原位检测 水文地球化学模拟 迁移转化 

分 类 号：P641.12[天文地球—地质矿产勘探]