摘要
运用吹扫-捕集气相色谱法测定了2017年夏季长江口及其邻近海域海水中4种常见的挥发性卤代烃(VHCs,包括一氟三氯甲烷(CFC-11)、碘甲烷(CH_3I)、三氯甲烷(CH3CCl3)和四氯乙烯(C_2Cl_4))以及大气中CFC-11、CH_3I和C_2Cl_4的浓度。结果表明,表层海水中4种VHCs浓度的水平分布受长江径流输入影响强烈,整体上呈现近岸高、远海低的趋势。垂直方向上4种VHCs浓度最高值出现在10m水层,长江口内断面的浓度整体高于口外断面的浓度。海水中VHCs的浓度分布受水文环境、生物释放和人为因素等的共同影响。相关性分析表明CH_3I与Chl a浓度不存在明显的相关性,而CFC-11与CH_3I、C_2Cl_4浓度存在显著相关性(P<0.01),表明调查海域人为源对CH_3I和C_2Cl_4的影响大于天然源。大气中CFC-11、CH_3I和C_2Cl_4的浓度分布整体上呈现近岸高、远海低的趋势。CFC-11的浓度低于全球平均值,表明我国CFC-11的排放得到了有效控制。后向轨迹分析表明来自近岸的陆源污染物的扩散和输送是调查海域大气中3种VHCs的重要来源。CFC-11、CH_3I和C_2Cl_4的海-气通量平均值分别为24.99nmol/(m2·d)、7.80nmol/(m2·d)、1.55nmol/(m2·d),表明夏季长江口及其邻近海域是大气中这3种VHCs的源。
The concentrations of four volatile halocarbons(VHCs)including CFC-11,CH 3 I,CH 3 CCl 3 and C 2 Cl 4 in the seawater of the Changjiang River Estuary and its adjacent marine area were determined by purge and trap-chromatography during the summer of 2016.Furthermore,CFC-11,CH 3 I,and C 2 Cl 4 concentrations in the marine atmosphere were also determined.The results showed that the concentrations of four VHCs in the coastal waters were higher than those in the open sea because of the influence of the Changjiang River runoff.In the vertical distributions,the four VHCs had a common feature with the maxima appearing in the 10 m layer.The concentrations of the VHCs were high inside the estuary(Section C)and low outside(Section A6).The distributions of the VHCs were influenced by water mass,biological production and terrestrial input.No correlation was observed between CH 3 I and chlorophyll a(Chl a)concentrations,while CFC-11 had significant positive correlations with CH 3 I and C 2 Cl 4(p<0.01),indicating that the influence of anthropogenic sources on CH 3 I was greater than that of natural sources.In the atmosphere,the concentration distributions of CFC-11,CH 3 I and C 2 Cl 4 showed a downtrend from inshore to offshore regions.The concentration of CFC-11 was lower than the global average,indicating that the emission of CFC-11 in China has been effectively controlled.The results of backward trajectory showed that the diffusion and transport of land-based pollutants from the nearshore was an important source of three kinds of VHCs in the marine atmosphere.The mean sea-to-air flux of CFC-11,CH 3 I and C 2 Cl 4 were respectively 24.99 nmol/(m 2·d),7.80 nmol/(m 2·d),1.55 nmol/(m 2·d),which indicated that the Changjiang River Estuary and its adjacent marine area acted as a source of atmospheric CFC-11,CH 3 I and C 2 Cl 4 in summer.
作者
汪浩
何真
张婧
杨桂朋
Wang Hao;He Zhen;Zhang Jing;Yang Guipeng(College of Chemistry and Chemical Engineering,Ocean University of China,Qingdao 266100,China;Laboratory for Marine Ecology and Environmental Science,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China)
出处
《海洋学报》
CAS
CSCD
北大核心
2018年第10期96-109,共14页
基金
国家重点研发计划项目(2016YFA0601304)
海洋国家实验室"鳌山人才"卓越科学家计划项目(2015ASTP)
关键词
挥发性卤代烃
长江口
分布
海-气通量
volatile halocarbon
Changjiang River Estuary
distribution
sea-to-air fluxes
