光照下青岛市降尘中汞的形态变化及其向大气的释放  

Mercury Release and Species Change in Dustfall of Qingdao Under Lighting

作　　者：李冬婷 伊丹 王艳[1,2] 刘汝海[1,2] 周续缘 莫冰 Li Dongting;Yi Dan;Wang Yan;Liu Ruhai;Zhou Xuyuan;Mo Bing(College of Environmental Science and Engineering,Ocean University of China,Qingdao 266100,China;Key Laboratory of Marine Environment and Ecology,Ministry of Education,Ocean University of China,Qingdao 266100,China)

机构地区：[1]中国海洋大学环境科学与工程学院,山东青岛266100 [2]中国海洋大学海洋环境与生态教育部重点实验室,山东青岛266100

出　　处：《中国海洋大学学报（自然科学版）》2024年第12期101-109,共9页Periodical of Ocean University of China

基　　金：山东省自然科学基金项目(ZR2023MD004,ZR2020MD118);国家自然科学基金项目(41506128)资助。

摘　　要：本研究采集了青岛市代表性的降尘样品,分析了降尘中汞的形态,并模拟太阳光下汞的再释放。结果表明,青岛市大气降尘中总汞含量为工业区(6.31 mg/kg)>高教区(1.01 mg/kg)>居民区(0.18 mg/kg)>交通区(0.10 mg/kg),且降尘中的汞以惰性汞(IPM)为主(占比90%以上),其次为活性汞(RPM)(平均占比为4.93%),挥发态汞(VPM)最小(平均占比为1.96%)。模拟太阳光照下初始释放量较高,随光照时间增加,释放量逐渐降低,颗粒物中汞的光还原符合准一级动力学反应。光照下降尘汞的释放量受其物质组成和形态的影响,光照强度越大,汞的释放量越高。太阳辐射促进了降尘颗粒物中不同形态汞的转化,光照后VPM与RPM含量减少,RPM更容易发生光化学反应而转化。本研究表明地表降尘是大气中汞的重要来源,为大气汞的再释放源。In this study,representative dustfall samples from Qingdao were collected,and the speciation of mercury in the dustfall was analyzed and the re-release of mercury under lighting was simulated.The results showed that the levels of total Hg in the dustfall in Qingdao were as follows:industrial district(6.31 mg/kg)>educational district(1.01 mg/kg)>residential district(0.18 mg/kg)>traffic district(0.10 mg/kg),and the Hg in dust was dominated by inert particle-phase mercury(IPM)(more than 90%)followed by reactive particle-phase mercury(RPM)(average of 4.93%),and volatile particle-phase mercury(VPM)(average of 1.96%)was the smallest.The initial release under lighting was high,and the amount of release gradually decreased with the increase of lighting time,and the photoreduction of mercury in dustfull conformed to the quasi-primary kinetic reaction.The release of mercury under lighting in dustfull was influenced by its material composition and speciation.The higher the light intensity,the higher the release of mercury.Light promoted the transformation of different speciation of Hg in dustfall,and the content of VPM and RPM decreased after light exposure,and RPM was more likely to be transformed by photochemical reactions.This study shows that surface dustfall is an important source of atmospheric mercury and a source of atmospheric mercury re-emission.

关 键 词：降尘 汞的形态 光照 释放 光还原 

分 类 号：X131.1[环境科学与工程—环境科学]