Distribution And Tracing Of HCFCs In Arctic Seawater

Chlorofluorocarbons(CFCs) in aspects of atmospheric environment research and climate change has been widespread concern, from the beginning of the 1970s, the research value of chlorofluorocarbon in the tracing ocean water system structure, ocean water mass movement and their interactions, water masses age, the air-sea exchange process increasingly significant. The late 1980s, chlorofluorocarbon production reached its peak. Before the implementation of its control over the world to CFCs, emissions to the atmosphere have reached 20 million tons. In recent decades, due to the release of a large amount of CFCs and other ozone-depleting substances that some of the ozone holes appear from time to time. Especially in the Antarctic ozone holes were observed each winter. Depletion data they observed this spring Arctic ozone were analyzed:the final confirmation of this magnitude to break the Arctic ozone depletion observation records, the first time appearance of hole like Antarctic ozone holes.In the international community, people generally use the purge and trap device designed by themselves to enrich seawater CFCs, and then use gas chromatography-electron capture detector for analysis testing. Combining with existing international research results, we developed a novel detection device of CFCs, and completed preliminary basic research applied to the Arctic waters of CFC-site measurements.We designed P&T-GC-ECD detection systems, we made an optimization of experimental conditions and a successful determination of four kinds of CFCs. The main experimental procedure:The 25 mL water sample injected into the purge chamber, and the range of flow rate of purge was 70 mL/min. The purge time of this method was 5 min, and trapping temperature was -37℃.The analytical temperature was 130℃, then the desorption time was 2.5 min. The pressure of GC gas was 0.066 MPa. Chromatographic column box temperature was 50℃, and detector temperature was 280℃.In this experiment, CFCs standard gas injection volume was 20μL, parallel determination three times to purge water samples for 1 h in water as a blank sample, a blank value determination, calculation of recovery. Recovery of CFC-12 was 98.8%± 1.5%, CFC-11 was 99.9%±1.8%, CFC-113 was 98.9%±3.9%, CC14 was 97.1%± 1.8%. This indicates a higher recovery of the act. The results showed that the measured precision of HCFCs in line with the requirements of the experimental analysis, CFC-12, CFC-11, CFC-113, CC14 relative standard deviation (RSD) were within 5%.This method is used to sample the fifth Arctic expedition determined to obtain a large number of reliable data that can be used to analyze the surface waters of the surface distribution of CFCs, vertical distribution and cross section distributions. And we used them to calculate the water mass movement and study water mass age.In order to provide support for deep water mass tracer,preliminary analysis of the relationship between CFCs concentration and temperature, salinity was made. The water mass of the BL sections of The Bering Sea are divided into groups of high temperature -low salinity, high temperature-high salinity, low temperature-low salinity and low temperature -high salinity water masses. From the perspective of CFCs concentration analysis, we can safely guess different temperature, salinity of water masses CFCs has its specific concentration range. In turn, CFCs can indicate changes in water masses, according to different concentrations of CFCs, as well as the different CFCs ratio to determine the source of the water masses are consistent.The Greenland Sea BB sections are divided into four kinds of water masses, such as high temperature-low salinity, high temperature-high salinity, low temperature-low salinity and low temperature -high salinity water masses. The Norwegian Sea AT sections are divided into three kinds of water masses such as high temperature-high salinity, low temperature-low salinity and low temperature -high salinity water masses. The authors use to produce their own charts, analysis CFCs concentration and determination of the ratio of their predecessors, put forward a reasonable doubt and analyze the reasons.PCFCs dating method using the Bering Sea, Norway-Mission apparent age of the Greenland waters were estimated. The results show:The age of these water masses from the pCFC-12 are distribution in 46 to 54 years, the age of these water masses from the pCFC-11 are distribution in 42 to 47 years. Through the Norwegian-Greenland waters computing age group, the age of these water masses from the pCFC-12 are distribution in the 40 to 54 years. The age of these water masses from the pCFC-11 are distribution in 43 to 59 years.