北极海水中氟氯烃分布特征和示踪研究

发布时间：2018-01-05 01:17

本文关键词：北极海水中氟氯烃分布特征和示踪研究　出处：《国家海洋局第一海洋研究所》2014年硕士论文　论文类型：学位论文

【摘要】：氟氯烃(CFCs)在大气环境科学、气候变化研究方面一直受到广泛的关注从二十世纪70年代开始,氟氯烃在示踪海洋水系结构、洋流水团运动及其相互作用、水团年龄、海气交换过程的研究价值日益显著。20世纪80年代后期,CFCs的生产达到了高峰,在对其实行控制之前,全世界向大气中排放的氟氯烃己达到了2000万吨。近几十年来,由于人类释放了大量氟氯烃等破坏臭氧的物质,臭氧层不时出现一些空洞,特别是在南极地区每年冬天都会观测到臭氧空洞。2011年确认北极臭氧减少幅度打破了观测记录,首次出现了类似南极上空的臭氧空洞。国际上普遍采用自行设计的吹扫捕集装置富集海水中氟氯烃,然后采用气相色谱一电子捕获检测器进行分析检测。本文结合国际上现有研究成果,自主开发了一种新型氟氯烃检测装置,并完成了应用于北极海水中氟氯烃现场测定的前期基础性研究。自行设计吹扫捕集-气相色谱-ECD检测系统,优化实验条件,成功测定四种CFCs。主要实验流程：将25 mL水样注入吹扫室中,吹扫气体为高纯氮气,流速70 mL/min,吹扫时间5 min,捕集温度-37℃,解析温度130℃,脱附时间2.5 min,使目标物进入气相色谱分离检测。气相色谱载气压力为0.066 MPa；色谱柱箱恒温50℃,检测器温度280℃。本实验以CFCs标准气体进样,体积为20μL,平行测定3次,以吹扫1 h的水样作为空白水样,测定空白值,计算回收率。回收率CFC-12为98.8%±1.5%,CFC-11为99.9%±1.8%,CFC-113为98.9%±3.9%,CC14为97.1%±1.8%,表明该法回收率较高。标准气体中的CFCs经低温吹扫捕集,再加热解析后进入气相色谱仪分析。结果表明,测得的氟氯烃的精密度符合分析实验的要求,CFC-12、CFC-11、CFC-113、CCl4的相对标准偏差(RSD)均在5%之内。将该方法用于测定第五次北极科考的海水样品,以北冰洋的白令海、白令海峡、楚科奇海及挪威-格陵兰海为研究海区,考察这些海区的CFCs的含量、分布与地形地貌及其它相关要素的关系；根据这些分布特征,研究北冰洋的水团表观年龄。我们初步分析CFCs浓度与温度、盐度的关系,以期对深层水团示踪提供支持。将白令海BL断面的水团分为高温低盐、高温高盐、低温低盐、低温高盐四种水团。从CFCs的浓度角度分析,我们可以大胆猜想不同温度、盐度的水团CFCs有其特定的浓度范围,反过来CFCs可以指示水团的变化,可以根据CFCs的不同浓度,以及不同CFCs之间的比值确定水团来源是否一致。将格陵兰海BB断面的水团分为高温低盐、高温高盐、低温低盐、低温高盐四种水团。将挪威海AT断面的水团分为高温高盐、低温低盐、低温高盐三种水团。运用自己制作的图表分析前人测定的CFCs浓度及比值,提出合理怀疑并分析原因。采用pCFCs定年法对白令海、挪威-格陵兰海的深层水团的表观年龄进行了估算。结果表明：对于白令海深层水团,pCFC-12算法得到年龄分布在46～54年,pCFC-11算法得到的年龄分布在42～47年。对于挪威-格陵兰海深层水团,pCFC-12算法得到水团年龄分布在40-54年,pCFC-11算法得到的水团年龄分布在43～59年。
[Abstract]:Chlorofluorocarbons (CFCs) in atmospheric environmental science, climate change research has attracted extensive attention from the beginning of twentieth Century 70s, CFCs in tracer of oceanic water structure, ocean water mass movement and the interaction between water age, air sea exchange of value increasingly prominent.20 century in late 80s, CFCs production reached a peak, before the in fact, for the whole world to control emissions in the atmosphere has reached 20 million tons of CFCs. In recent decades, due to the release of a large number of human CFCs and other ozone destroying the ozone layer material, from time to time, some of the holes, especially the ozone hole observed.2011 years to confirm the Arctic ozone reduction broke the record in the Antarctic region every winter for the first time, similar to the Antarctic ozone hole. The commonly used international designed by Purge and trap device in seawater fluoride enrichment Chlorinated hydrocarbon, then using gas chromatography with electron capture detector was used for analysis. Based on existing research results, developed a new kind of CFC detection device, and completed the early basic research was applied to the determination of the Arctic sea chlorofluorocarbons site. Since the design of purge and trap gas chromatography with -ECD detection the system, optimizing the experimental conditions, the successful determination of four CFCs. experimental procedures: 25 mL water injected into the purge chamber, a purge gas for high pure nitrogen flow rate of 70 mL/min, 5 min purge time, trapping temperature is -37 DEG C, analytical 130 degrees Celsius temperature, desorption time of 2.5 min, which entered into gas phase chromatographic separation of gas chromatography to detect the target. The pressure of the gas is 0.066 MPa; chromatographic column box with constant temperature of 50 DEG C, the detector temperature is 280 degrees centigrade. In this experiment, the CFCs standard gas sampling volume, 20 L, 3 determinations to purge 1 h water as the blank sample Determination of blank value, the recovery rate was calculated. The recovery rate of CFC-12 was 98.8% + 1.5%, CFC-11 = 99.9% + 1.8% + 3.9%, CFC-113 was 98.9%, CC14 was 97.1% + 1.8%, shows that the recovery rate is high. The standard CFCs in the gas by cryogenic purge and trap, and then enters the heating analytical gas chromatography analysis. The results show that the measured precision according to experimental analysis of chlorofluorocarbons requirements, CFC-12, CFC-11, CFC-113, the relative standard deviation of CCl4 (RSD) were within 5%. The method for the determination of fifth seawater samples of the Arctic expedition to the Arctic, Bering Sea, Bering Sea and the Norway gorge, Chukotka the Greenland Sea as the research area, the area of CFCs was studied. The relationship between distribution and topography and other related factors; according to the distribution feature of the water table of the Arctic ocean view, age. Our preliminary analysis of CFCs concentration and temperature, salinity, in order to deep Layer water mass tracer to provide support. The BL section of the Bering Sea water is divided into high temperature and low salinity, high temperature and high salinity, low temperature and low salinity, low temperature and high salinity water masses in four. From the analysis of the concentration of CFCs angle, we can safely assume that different temperature, salinity of the water masses CFCs has its specific concentration range, CFCs can reverse changes indicating water, according to the different concentration of CFCs, and the ratio between different CFCs to determine whether the source of water. The water masses in the Greenland Sea BB section is divided into high temperature and low salinity, high temperature and high salinity, low temperature and low salinity, low temperature and high salinity water masses. The four kinds of water masses in Norway sea AT section is divided into high temperature and high salinity. Low temperature and low salinity, low temperature and high salinity water masses. Three kinds of use to produce their own chart analysis of CFCs concentration and the ratio of the previous determination, reasonable doubt and analyze the reasons. The pCFCs dating of the Bering Sea, the concept of age in deep water table of the Greenland Sea - Norway It was estimated. The results show that: for the Bering Sea in deep water, the age ranged from 46 to 54 years of pCFC-12 algorithm, pCFC-11 algorithm is the age distribution in 42 ~ 47 years. For the Norway Greenland Sea deep water, get water age distribution in 40-54 pCFC-12 algorithm, pCFC-11 algorithm to get the water age distribution in 43 ~ for 59 years.

【学位授予单位】：国家海洋局第一海洋研究所
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P734

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