大气颗粒态汞的粒径分布特征及风险评价——以天津城区样品为例  

Particle Size Distribution and Risk Assessment of Atmospheric Particle-Bound Mercury——A Case Study of Samples from Tianjin Urban Area

作　　者：樊熊菲 张可[1] 郑旺 范雨生 帅旺财 袁圣柳 陈玖斌 FAN Xiongfei;ZHANG Ke;ZHENG Wang;FAN Yusheng;SHUAI Wangcai;YUAN Shengliu;CHEN Jiubin(Institute of Surface-Earth System Science,School of Earth System Science,Tianjin University,Tianjin 300072,China;Chemistry Department,Trent University,Peterborough Ontario,Canada)

机构地区：[1]天津大学地球系统科学学院表层地球系统科学研究院,天津300072 [2]Chemistry Department,Trent University,Peterborough Ontario,Canada

出　　处：《地球与环境》2022年第3期328-339,319,共13页Earth and Environment

基　　金：国家自然科学基金青年科学基金项目(41903014);国家自然科学基金重点项目(41830647)。

摘　　要：颗粒态汞在大气中停留时间短、易沉降,易对局地环境与人体健康造成危害,明确不同粒径颗粒态汞的分布,对进一步认知大气汞循环及环境归趋具有重要意义。本文讨论了2018年天津市四季大气颗粒态汞的粒径分布特征及季节性差异,判定了其可能来源,评估了其潜在生态和人体健康风险。结果表明,受初级排放源及活性气态汞的气-粒分配影响,颗粒态汞在PM_(<0.5)、PM_(<0.5-1)粒径中明显富集,其环境健康危害一直被低估。大气颗粒态汞的平均浓度为181.1±97.2 pg/m^(3),冬季浓度较高,可能受人为排放量大、沉降率低、气-粒分配系数K;与温度成反比因素控制。夏季浓度较低,除受清洁海相气团影响外,天气潮湿,汞的清除作用加大也是重要因素。颗粒态汞来源不同,冬季主要来源于北方燃煤供暖,春秋季与日常工业生产、车辆排放相关,夏季受自然源海相气团影响较大。尽管大气颗粒态汞通过呼吸给人体带来的健康风险较低,但细粒径风险值显著高于粗粒径,且其具有很强的生态环境危害,需要得到高度重视。Mercury(Hg)is a toxic heavy metal that exists in environment ubiquitously.Although the proportion of particle-bound mercury(Hg^(p))in the atmosphere is less than 10%,it has a short residence time and readily deposits,causing environmental and health hazards.Thus,clarifying the distribution of Hg^(p)in atmospheric particles of different sizes is of great importance for understanding the fate of atmospheric Hg and its post-depositional effect on surface ecosystem.In this study,fine particles of different grain sizes collected in Tianjin in 2018 were analyzed to characterize the size distribution and seasonal variation of Hg^(p),the possible sources of Hg^(p),and to evaluate the human health risks and potential ecological risks of Hg^(p).The result showed that Hg^(p)was significantly enriched in PM_(<0.5)andPM_(<0.5-1)due to primary emission sources and gas-particle distribution,and its health and environmental hazards have been underestimated.The concentration of Hg^(p)in the winter,spring,and autumn of 2018 was highest in PM;,while in summer it enriched in a relatively coarse particle size of PM;.There were different sources of atmospheric Hg^(p)in the four seasons of Tianjin in 2018.The winter was closely related to coal-fired heating,while the spring and autumn were mainly related to industrial production and vehicle emissions,and the summer was greatly affected by marine air masses,which was mainly emitted from natural background.The average concentration of Hg^(p)in TSP was 181.1±97.2 pg/m^(3),with the highest appeared in winter and lowest in summer.The highest concentration of Hg^(p)in winter likely resulted from intense emissions,low sedimentation rate and the high gas-particle distribution coefficient K;that was inversely proportional to temperature.On the other side,the lowest concentration in summer was mainly controlled by the clean marine air mass,and the humid weather in summer favoring the Hg removal.Though the health risk of atmospheric Hg^(p)to the human body through the respiratory route was low,t

关 键 词：颗粒态汞 粒径分布 季节性变化 生态风险 

分 类 号：X513[环境科学与工程—环境工程]