稳定同位素技术在地表水硝酸盐污染研究中的应用  

Application of stable isotope on nitrate pollution researches of surface water

作　　者：丁京涛[1] 席北斗[2] 许其功[2] 高如泰[2] 卢义[3] 黄健[1] 刘鸿亮[2] 

机构地区：[1]北京师范大学环境学院,北京100875 [2]中国环境科学研究院,北京100012 [3]重庆交通大学河海学院,重庆400000

出　　处：《湖泊科学》2013年第5期617-627,共11页Journal of Lake Sciences

基　　金：国家水体污染控制与治理科技重大专项项目(2012ZX07101-002)资助

摘　　要：地表水硝酸盐污染已成为全球面临的主要水环境问题之一,为了有效控制地表水中硝酸盐污染,确定地表水中硝酸盐的来源以及研究其在环境中的迁移转化过程就显得尤为重要.硝酸盐稳定氮(15N)、氧(18O)同位素作为一种有效的示踪技术在识别地表水中硝酸盐的来源及迁移转化过程中已得到了广泛的应用,但是硝酸盐在迁移转化过程中,15N、18O同位素会因为多种因素而发生分馏,同位素值发生变化使得这种技术的应用存在一定的局限性.本文系统总结了不同来源硝酸盐δ15N、δ18O值的组成特征及其影响因素,分析了在不同土地利用类型流域内,利用硝酸盐15N、18O同位素技术开展硝酸盐来源识别、负荷估算和反硝化作用评估的方法和研究进展.基于已有研究成果,提出在未来的研究过程中,一方面应以流域为单元,选择适当的研究方法并结合多种辅助指标研究多因素共同作用下NO-3污染源的δ15N-NO-3和δ18O-NO-3值的变化规律;另一方面应对比流域污染源详细的调查数据,分析现有负荷估算模型存在的不确定性,并构建合适的负荷计算模型;最后,应深入开展同位素在确定流域和河流中反硝化发生的范围、地点和程度方面的研究,特别是掌握河流系统中沉积物-水体中氮的循环过程.Since nitrate contamination in surface water is an environmental problem in many regions of the world, methods to trace the source of nitrate and its transformation mechanisms are important for nitrate pollution control. Nowadays, stable nitrogen （15N） and oxygen （ Is O ） isotope data can provide meaningful insight for tracing sources of nitrate and have been frequently used to identify nitrate source and its transformation mechanisms in surface water. However, the stable isotope methods have limitations be- cause the complex fractionations caused by multiple N-cycling processes can change the original isotopic values. This review paper systematically summarizes the isotopic composition and its influencing factors of various nitrate sources, the techniques and progres- ses in research on nitrate sources identification, and load estimation and assessment of denitrifieation in different types of land-use watersheds using nitrate stable isotope methods. Based upon the previous researches about the application of stable isotope meth- ods, we suggest that in the future it is important to treat a catchment as a unit and to apply several assisted indexes to study the var- iation of $15 N-NO3- and 61s O-N03- in different sources under the combined effects of multiple factors. In addition, comparative studies should be conducted to assess the uncertainty between polluting source survey data and the results of model simulation, and to build a better load computational model. Finally, further studies should be made to investigate the scale and extent of denitrifiea- tion in a catchment/river using the nitrate stable isotope methods, especially in the sediment-water system.

关 键 词：硝酸盐 污染源识别 地表水 稳定同位素 反硝化 

分 类 号：X131.2[环境科学与工程—环境科学]