南京大学学报(自然科学版) ›› 2019, Vol. 55 ›› Issue (2): 301–308.doi: 10.13232/j.cnki.jnju.2019.02.015

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不同土地利用单元汇水径流中氮的同位素特征及其转化途径解析

乐　凡1,2，李荣富1,2，马天海3，闫中月1,2，阮晓红1,2*   

  1. 1. 南京大学表生地球化学教育部重点实验室，南京，210023； 2．南京大学地球科学与工程学院水科学系，南京，210023； 3. 南京大学金陵学院，南京，210089
  • 接受日期:2018-11-27 出版日期:2019-04-01 发布日期:2019-03-31
  • 通讯作者: 阮晓红 E-mail:ruanxh@nju.edu.cn
  • 基金资助:
    水体污染控制与治理科技重大专项(2017ZX07602003)，江苏省水利科技项目(2016022)

Analyses of isotopic characteristics and transformations of nitrogen in the runoff of sub－catchments with various land uses

Le Fan1,2，Li Rongfu1,2，Ma Tianhai3，Yan Zhongyue1,2，Ruan Xiaohong1,2*   

  1. 1.MOE Key Laboratory of Suficial Geochemistry，Nanjing University，Nanjing，210023，China； 2.Department of Hydro Sciences，School of Earth Sciences and Engineering，Nanjing University，Nanjing，210023，China； 3.Nanjing University，Jinling College，Nanjing，210089，China
  • Accepted:2018-11-27 Online:2019-04-01 Published:2019-03-31
  • Contact: Ruan Xiaohong E-mail:ruanxh@nju.edu.cn

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摘要： 不同来源氮的δ15N值域存在重叠，导致δ15N溯源结果存在不确定性，因此对δ15N溯源结果的校验具有重要意义. 淮河入海水道具有明确的汇水分区及差异的土地利用方式，为δ15N溯源结果验证提供了良好的研究场所. 基于2017年枯、丰水期淮河入海水道水体δ15N，δ18O值域特征，结合汇水片区土地利用方式，甄别并校验了氮的主要来源；综合15N，18O分馏特征，探讨了氮的转化途径. 结果表明：(1)运西高片和通榆低片农业区，农田退水分别通过古盐河及沿程汇流入河，其δ15N－NO－3分别为6.4‰±0.4‰和7.9‰±0.8‰，验证了土壤氮δ15N与理论值(0～8‰)的一致性；δ15N－NH＋4分别为8.4‰±9.0‰和23.5‰±7.6‰，表明NH＋4来源于沿河生活污水. 而两运夹城镇区，片区污水排放通道清安河δ15N－NO－3和δ15N－NH＋4分别高达25.9‰和40.3‰，基本位于城镇污水δ15N理论值(4‰～35‰). (2)运东高片城镇和农业混合区，区域汇水沿程入河，其δ15N－NO－3为7.7‰～11.6‰，位于土壤氮和城镇污水δ15N重叠区；而δ15N－NH＋4为17.9‰±7.3‰，显示了城镇污水δ15N特征. (3)沿程取样点δ18O－NO－3为3.5‰±5.1‰，位于硝化作用理论范围(－5‰～15‰)，表明发生了持续的硝化过程；沿程δ15N－NO－3和δ18O－NO－3无同步富集，表明反硝化过程不显著．

关键词: 氮同位素, 氮溯源校验, 迁移转化途径, 土地利用类型, 汇水分区

Abstract: Due to the overlap of δ15N range among various nitrogen sources，it is of great significance to assess the uncertainty of nitrogen sources identification based on isotope approach. The Huaihe River Channel(HRC)watershed，which consists of distinct sub－catchments and typical land use types，provides an ideal study area to verify nitrogen sources identification based on δ15N. In the present study，water samples were collected during the dry and wet seasons in 2017. The values of δ15N and δ18O，and characteristics of the catchment runoff and land uses were analyzed to elucidate the sources of nitrogen.Furthermore，15N and18O fractionation characteristics were analyzed to reveal the dominant nitrogen transformation pathways. The results showed that agricultural drainage area within Yunxi and Tongyu flowing into the HRC by Guyan River or through the runoff along the HRC has mean δ15N－NO－3 values 6.4‰±0.4‰ and 7.9‰±0.8‰，respectively，which were consistent with the previously reported δ15N end member of soil organic nitrogen(0～8‰)，while the mean δ15N－NH＋4 values were 8.4‰±9.0‰，23.5‰±7.6‰，respectively，indicating that NH＋4 mainly derived from rural sewage along the river. In the urban area of Liangyunjia，domestic sewage is discharged through Qing’an river. Measured δ15N－NO－3 and δ15N－NH＋4 were as high as 25.9‰ and 40.3‰，which were higher than most of the reported δ15N values of sewage(4‰～35‰). In the mixing area of Yundong between agricultural and urban，catchment runoff flows into the HRC along the river. Measured δ15N－NO－3 value(7.7‰～11.6‰)was located in the overlap δ15N range of soil organic nitrogen and sewage，while δ15N－NH＋4 value(17.9‰±7.3‰)suggested that NH＋4 mainly derived from urban sewage. All δ18O－NO－3 values were located in theoretical δ18O range of nitrate derived from nitrification，suggesting that nitrification was the dominant transformation pathway. Denitrification may have not predominantly occurred in the overlying water according to the absence of synchronous enrichment of15N and18O of nitrate.

Key words: nitrogen isotope, nitrogen sources identification and verification, transformation pathways, land use, catchment runoff

中图分类号: 

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[1]　Liu C Q，Li S L，Lang Y C，et al. Using δ15N－and δ18O－values to identify nitrate sources in karst groundwater，Guiyang，Southwest China. Environmental Science & Technology，2006，40(22)：6928－6933.
[2] Ma Y，Song X F. Using stable isotopes to determine seasonal variations in water uptake of summer maize under different fertilization treatments. Science of the Total Environment，2016，550：471－483.
[3] Yang Y Y，Toor G S. δ15N and δ18O reveal the sources of nitrate－nitrogen in urban residential stormwater runoff. Environmental Science & Technology，2016，50(6)：2881－2889.
[4] Xue D M，Botte J，De Baets B，et al. Present limitations and future prospects of stable isotope methods for nitrate source identification in surface－ and groundwater. Water Research，2009，43(5)：1159－1170.
[5] Nikolenko O，Jurado A，Borges A V，et al. Isotopic composition of nitrogen species in groundwater under agricultural areas：A review. Science of the Total Environment，2018，621：1415－1432.
[6] Silva S R，Ging P B，Lee R W，et al. Forensic applications of nitrogen and oxygen isotopes in tracing nitrate sources in urban environments. Environmental Forensics，2002，3(2)：125－130.
[7] Amberger A，Schmidt H L. Natural isotope contents of nitrate as indicators for its origin. Geochimica et Cosmochimica Acta，1987，51：2699－2705.
[8] Li S L，Liu C Q，Li J，et al. Assessment of the sources of nitrate in the Changjiang River，China using a nitrogen and oxygen isotopic approach. Environmental Science & Technology，2010，44(5)：1573－1578.
[9] Liang X Q，Nie Z Y，He M M，et al. Application of15N－18O double stable isotope tracer technique in an agricultural nonpoint polluted river of the Yangtze Delta Region. Environmental Science and Pollution Research，2013，20(10)：6972－6979.
[10] 李荣富，罗跃辉，曾洪玉等. 稳定同位素技术在环境水体氮的生物地球化学循环研究中的应用. 南京大学学报(自然科学版)，2016，52(1)：16－26.(Li R F，Luo Y H，Zeng H Y，et al. Review on applications of stable isotope techniques in studying biogeochemical cycle of nitrogen in environmental water. Journal of Nanjing University(Natural Sciences)，2016，52(1)：16－26.)
[11] Li Y L，Li Y F，Zhao T Q，et al. Identifying nitrate sources and transformations in Taizi River Basin，Northeast China. Environmental Science and Pollution Research，2017，24(25)：20759－20769.
[12] Samantara M K，Padhi R K，Satpathy K K，et al. Groundwater nitrate contamination and use of Cl/Br ratio for source appointment. Environmental Monitoring and Assessment，2015，187(2)：50.
[13] Nakagawa K，Amano H，Takao Y，et al. On the use of coprostanol to identify source of nitrate pollution in groundwater. Journal of Hydrology，2017，550：663－668.
[14] Meghdadi A，Javar N. Quantification of spatial and seasonal variations in the proportional contribution of nitrate sources using a multi－isotope approach and Bayesian isotope mixing model. Environmental Pollution，2018，235：207－222.
[15] Han L，Huang M S，Ma M H，et al. Evaluating sources and processing of nonpoint source nitrate in a small suburban watershed in China. Journal of Hydrology，2018，559：661－668.
[16] Gu B H. Stable isotopes as indicators for seasonally dominant nitrogen cycling processes in a subarctic lake. International Review of Hydrobiology，2012，97(3)：233－243.
[17] Rock L，Ellert B H，Mayer B. Tracing sources of soil nitrate using the dual isotopic composition of nitrate in 2 M KCl－extracts. Soil Biology and Biochemistry，2011，43(12)：2397－2405.
[18] Sigman D M，Casciotti K L，Andreani M，et al. A bacterial method for the nitrogen isotopic analysis of nitrate in seawater and freshwater. Analytical Chemistry，2001，73(17)：4145－4153.
[19] Casciotti K L，Sigman D M，Galanter Hastings M，et al. Measurement of the oxygen isotopic composition of nitrate in seawater and freshwater using the denitrifier method. Analytical Chemistry，2002，74(19)：4905－4912.
[20] Hosono T，Tokunaga T，Kagabu M，et al. The use of δ15N and δ18O tracers with an understanding of groundwater flow dynamics for evaluating the origins and attenuation mechanisms of nitrate pollution. Water Research，2013，47(8)：2661－2675. [21] 岳甫均，李　军，刘小龙等. 利用氮同位素技术探讨天津地表水氮污染. 生态学杂志，2010，29(7)：1403－1408.(Yue F J，Li J，Liu X L，et al. Nitrogen pollution of surface water in Tianjin based on nitrogen isotope approach. Chinese Journal of Ecology，2010，29(7)：1403－1408.)
[22] Mengis M，Schif S L，Harris M，et al. Multiple geochemical and isotopic approaches for assessing ground water NO－3 elimination in a riparian zone. Groundwater，1999，37(3)：448－457.
[23] Andersson K K，Hooper A B. O2 and H2O are each the source of one O in NO－2 produced from NH3 by Nitrosomonas：15N－NMR evidence. FEBS Letters，1983，164(2)：236－240.
[24] Kendall C，Euiott E M，Wankel S D. Tracing anthropogenic inputs of nitrogen to ecosys－tems ∥ Michener R，Lajtha K. Stable Isotopes in Ecology and Environmental Science. 2nd ed. Malden，MA：Blackwell Publishing，2007：375－449.
[25] Granger J，Sigman D M，Rohde M M，et al. N and O isotope effects during nitrate assimilation by unicellular prokaryotic and eukaryotic plankton cultures. Geochimica et Cosmochimica Acta，2010，74(3)：1030－1040.
[26] Casciotti K L. Inverse kinetic isotope fractionation during bacterial nitrite oxidation. Geochimica et Cosmochimica Acta，2009，73(7)：2061－2076.
[27] 丁京涛，席北斗，许其功等. 稳定同位素技术在地表水硝酸盐污染研究中的应用. 湖泊科学，2013，25(5)：617－627.(Ding J T，Xi B D，Xu Q G，et al. Application of stable isotope on nitrate pollution researches of surface water. Journal of Lake Sciences，2013，25(5)：617－627.)
[28] Matiatos I. Nitrate source identification in groundwater of multiple land－use areas by combining isotopes and multivariate statistical analysis：A case study of Asopos basin(Central Greece)．Science of the Total Environment，2016，541：802－814.
[29] Yue F J，Li S L，Liu C Q，et al. Tracing nitrate sources with dual isotopes and long term monitoring of nitrogen species in the Yellow River，China. Scientific Reports，2017，7(1)：8537.
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