动态顶空-箱式法在湖泊挥发性有机物释放观测中的应用  

Application of Dynamic Headspace-Static Box in Observation of VOCs Released from Lakes

作　　者：余益军 沈伟[1] 程钟 于红霞 YU Yijun;SHEN Wei;CHENG Zhong;YU Hongxia(Changzhou Environmental Monitoring Centre,Changzhou 213001,China;State Key Laboratory of Pollution Control and Resource Reuse,School of the Environment,Nanjing University,Nanjing 210023,China)

机构地区：[1]江苏省常州环境监测中心,江苏常州213001 [2]污染控制与资源化研究国家重点实验室,南京大学环境学院,江苏南京210023

出　　处：《中国环境监测》2022年第2期96-103,共8页Environmental Monitoring in China

基　　金：江苏省省级环保科研课题(2019023);江苏省环境监测科研基金项目(1603)。

摘　　要：湖泊是挥发性有机物(VOCs)的重要自然源,适用的观测手段是湖泊VOCs释放研究的基础。该研究以人工观测池模拟水华水体,以动态顶空-箱式法收集水气界面释放的VOCs,联用甲烷-非甲烷总烃分析仪和飞行时间质谱仪,并辅以阀切换,实现野外2种场景VOCs释放的同时高时间分辨率在线观测。结果表明,合理设置参数后方法重现性好、精度高,相对偏差绝大部分在±10%内;直接进样-氢火焰离子化检测、膜富集-飞行时间质谱检测分别适用于水面释放甲烷和非甲烷VOCs的观测。人为引入浓藻的试验池甲烷、非甲烷VOCs释放速率分别为66.2、2.18 mg/(m^(2)·d),而对照池则分别为2.39、1.15 mg/(m^(2)·d),正午前后非甲烷VOCs释放强度大,傍晚至凌晨则甲烷释放强烈;经试验组、对照组的差异对比以及试验组内物质释放速率之间相关性分析,初步推断藻类释放了壬烷、癸烷、异戊二烯、苯乙烯、氯苯、二氯苯、三氯苯、三氯乙烯、四氯乙烯等物质。Lake is a neglected but also an important natural source of volatile organic compounds(VOCs).Observation methods with high time resolution are the basis for the field study of VOCs release from lakes,while few related works have been reported.In this study,a static box combined with a methane/non-methane hydrocarbon analyzer and an online Time-of-Flight Mass Spectrometry(TOF/MS)were employed to achieve real-time observation of VOCs released from lakes.Released behaviors in two scenes were determined simultaneously with high time resolution based on valve switching in the field.By proper setting of the valve switching,the method showed good reproducibility and accuracy and the relative deviation was mostly within±10%.The release rates of methane and TVOC from the test pool were 66.2 and 2.18 mg/(m^(2)·d),respectively,while those for the control were 2.39 and 1.15 mg/(m^(2)·d),indicating the methane pathway was more important than other VOCs pathways in the carbon circulation of algal cells.Peak period of methane release was found in the evening to early morning,while that for other VOCs was at noon.Analysis of VOCs’release rates on the test and control indicated that algae cells could release nonane,decane,isoprene,styrene,chlorobenzene,dichlorobenzene,trichlorobenzene,trichloroethylene,tetrachloroethylene and so on,in which many of these substances were generally considered to be from human sources.

关 键 词：藻类 挥发性有机物 释放 自然源 

分 类 号：X823[环境科学与工程—环境工程]