| 汪浩,何真,张婧,杨桂朋.夏季长江口及其邻近海域挥发性卤代烃的分布和海-气通量研究[J].海洋学报,2018,40(10):96-109 |
| 夏季长江口及其邻近海域挥发性卤代烃的分布和海-气通量研究 |
| Distribution characteristics and sea-to-air fluxes of volatile halocarbons in the Changjiang River Estuary and its adjacent marine area in summer |
| 投稿时间：2018-04-24 修订日期：2018-06-13 |
| DOI：10.3969/j.issn.0253-4193.2018.10.010 |
| 中文关键词: 挥发性卤代烃 长江口 分布 海-气通量 |
| 英文关键词:volatile halocarbon Changjiang River Estuary distribution sea-to-air fluxes |
| 基金项目: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）。 |
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| 中文摘要: |
| 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（CH3I）、三氯甲烷（CH3CCl3）和四氯乙烯（C2Cl4））以及大气中CFC-11、CH3I和C2Cl4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10 m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CH3I与Chl a浓度不存在明显的相关性，而CFC-11与CH3I、C2Cl4浓度存在显著相关性（P<0.01），表明调查海域人为源对CH3I和C2Cl4的影响大于天然源。大气中CFC-11、CH3I和C2Cl4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、CH3I和C2Cl4的海-气通量平均值分别为24.99 nmol/（m2·d）、7.80 nmol/（m2·d）、1.55 nmol/（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。 |
| 英文摘要: |
| The concentrations of four volatile halocarbons (VHCs) including CFC-11, CH3I, CH3CCl3 and C2Cl4 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, CH3I, and C2Cl4 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 CH3I and chlorophyll a (Chl a) concentrations, while CFC-11 had significant positive correlations with CH3I and C2Cl4(p<0.01), indicating that the influence of anthropogenic sources on CH3I was greater than that of natural sources. In the atmosphere, the concentration distributions of CFC-11, CH3I and C2Cl4 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, CH3I and C2Cl4 were respectively 24.99 nmol/(m2·d), 7.80 nmol/(m2·d), 1.55 nmol/(m2·d), which indicated that the Changjiang River Estuary and its adjacent marine area acted as a source of atmospheric CFC-11, CH3I and C2Cl4 in summer. |
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