摘要
CFCs是一种合成的含氯离子和氟离子的有机化学品,主要组成包括CFC-11、CFC-12与CFC-113等。其自1930年以来开始被大量生产,年生产量达106t。由于其具有挥发性与良好的化学稳定性,通过量化地下水中CFCs的平衡分压,将该平衡分压与大气CFCs浓度变化标准曲线进行对比,即可确定目标区域地下水的年龄。自20世纪70年代中期美国首次尝试利用CFCs用于研究地下水年龄以来,国际上日益重视,广泛开展了其在确定地下水年龄、揭示浅层地下水和深层地下水之间的水力联系、确定地下水各种来源水的混合比例等地下水循环演化方面的研究,但目前中国等发展中国家对该技术的研究及应用还处于初步发展阶段。从CFCs的特性、生产及环境释放入手,阐述CFCs测试技术的关键环节——地下水的野外采样、CFCs的提取、测定及CFCs方法测定地下水年龄的原理与计算方法,并以全球视角对CFCs年龄示踪技术在国内外的应用进行综述。在比较分析目前测定地下水年龄测定的主要方法中,指出CFCs环境示踪技术相比SF6、3H/3He等其它环境示踪技术具有分析便捷、价格适中、精度较高的显著优点,特别是在已经做过历年大气CFCs浓度监测等相关研究的地区的应用。
Chlorofluorocarbons （CFCs） have been widely used as tools and tracers to date younger groundwater over the world in the past 30 years. CFCs such as CFC-11, CFC-12 and CFC-113 are organic compounds that contain chlorine and fluorine. They have been largely produced since the 1930s and the annual world production of CFCs peaked with 106 metric tons. CFCs can accumulate in the atmosphere and are responsible for depleting stratospheric ozone. Because of their volatile and chemical stability, we can date the groundwater age in the target area through contrasting the equilibrium pressure of CFCs in groundwater with the standard curve of CFCs concentration in the atmosphere. Since the first time use of CFCs to date groundwater age in United States in the mid-1970s, CFCs groundwater age-dating has attracted much attention. The CFCs technique is used to date groundwater age, reveal the hydraulic linkage between shallow and deep groundwater, and estimate the various groundwater recharge sources. However, this technology has not been well adopted and evaluated in developing countries such as China. This article introduces the characteristics, production and emission of CFCs, presents the key procedures of CFCs groundwater testing such as field sampling, extraction and determination of CFCs, and age dating, and reviews the applications of using the CFCs groundwater age-dating technique. Comparing to the groundwater age-dating techniques using other tracers （SFr, 3H/3He, etc.）, the CFCs technique offers significant advantages in terms of simplicity, reduced costs, and high accuracy, especially for the research areas where the atmospheric concentration of CFCs has been monitored. We conclude that the CFCs groundwater age-dating technique should prove useful and valuable in groundwater-related research and application.
出处
《生态环境学报》
CSCD
北大核心
2012年第8期1503-1508,共6页
Ecology and Environmental Sciences
基金
中国科学院"百人计划"项目
作者简介
作者简介：李静（1984年生），女，助理研究员，博士，主要从事生态系统管理研究。E-mail：jingli@igsnrr．ac．cn
通信作者：李发东（1972年生），男，研究员，博士，博士生导师，中国科学院百人计划入选者，主要从事生态水文与水环境研究。E—mail：lifadong@igsnrr．ac．cn
