汞矿区稻田土壤汞形态分布特征及对甲基化的影响  

Distribution Characteristics of Mercury Occurrences in the Paddy Soil of Hg Mining Area and its Effect on Mercury Methylation

作　　者：陆本琦 刘江 吕文强 黎珊 冯新斌[1] 孟博[1] LU Ben-qi;LIU Jiang;LYU Wen-qiang;LI Shan;FENG Xin-bin;MENG Bo(State Key Laboratory of Environmental Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China;University of Chinese Academy of Sciences,Beijing 100049,China;School of Geography and Resources,Guizhou Education University,Guiyang 550018,China)

机构地区：[1]中国科学院地球化学研究所,环境地球化学国家重点实验室,贵阳550081 [2]中国科学院大学,北京100049 [3]贵州师范学院地理与资源学院,贵阳550018

出　　处：《矿物岩石地球化学通报》2021年第3期690-698,共9页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家自然科学基金项目(U1612442,42022024,41931297);中国科学院西部青年学者A类项目。

摘　　要：汞污染区稻米甲基汞超标现象普遍存在,汞在土壤中的形态分布被认为是影响甲基化过程的重要因素之一。本研究选取贵州省万山废弃汞矿区和土法炼汞区为研究区域,在水稻生长期间对稻田土壤剖面中总汞、甲基汞及形态汞进行测定,结合土壤环境因子指标,讨论土壤汞形态分布特征对甲基化的影响。研究表明,汞矿区稻田土壤中总汞和甲基汞均表现出随土壤深度加深而逐渐降低的趋势,且主要以有机结合态和残渣态形式存在,占总汞的98%以上。在废弃汞矿区,不同形态汞可能会转化为生物难以利用的形态:溶解态与可交换态、特殊吸附态与氧化态汞可能先转变为有机结合态,再转变为残渣态汞。在土法炼汞区表现为硫酸盐还原与铁还原过程驱动的汞甲基化过程,并且有机结合态汞可能也参与了甲基化过程。The concentration of methylmercury(MeHg) in rice is usually high in mercury(Hg) contaminated areas. The Hg occurrence in soil is considered as an important factor influences methylation processes. This study analyzed total Hg(THg), MeHg, Hg occurrences and environmental factors in the rice paddy soil profiles from an abandoned mercury mining area and an artisanal mining area in Wanshan, Guizhou, and discussed effects of soil’s Hg occurrences on methylation. Results showed that concentrations of THg and MeHg in paddy soils decreased gradually along the soil profiles. Organic-bound and residual Hg forms were predominated forms, accounting for more than 98% of THg in soils. In the abandoned Hg mining area, Hg immobilized by transforming processes of from soluble, exchangeable, specifically sorbed, or/and oxide-bound Hg forms to the organic-bound Hg form and even to the residual Hg form. In the artisanal mining area, the Hg methylation were mediated by sulfate reduction and iron reduction, and the organic-bound Hg might have been involved in the methylation process.

关 键 词：汞 甲基汞 稻田土壤 汞形态 

分 类 号：P595[天文地球—地球化学]