| 太子河流域中游地区河流硝酸盐来源及迁移转化过程 |
| 摘要点击 3597 全文点击 1243 投稿时间：2017-04-25 修订日期：2017-06-18 |
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| 中文关键词 硝酸盐 稳定同位素 氯离子 太子河流域 来源示踪 |
| 英文关键词 nitrate stable isotopes chloride Taizi River source tracing |
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| 中文摘要 |
| 选取太子河中游地区为研究对象，联合硝酸盐（NO3-）、氯离子（Cl-）、硝酸盐氮、氧同位素（δ15N和δ18O）和水的氧同位素（δ18O）识别不同季节2016年5月和8月（对应枯水期和丰水期）地表水硝酸盐来源及迁移转化过程.结果表明通过Man-Whitney U检验，枯水期ρ（Cl-）、ρ（NO3-）、ρ（NH4+-N）和δ18O-NO3-显著高于丰水期，δ15N-NO3-无显著时间差异.根据NO3-/Cl-，δ15N-NO3-和δ18O-NO3-的范围，发现不同采样期，硝酸盐主要来自于多种源的混合.丰水期，细河、蓝河和下达河硝酸盐来源是化学肥料、土壤氮和生活污水及畜禽粪便排放废水.二道河主要是土壤氮和化学肥料.枯水期，下达河硝酸盐主要来自于化学肥料和土壤氮，细河、蓝河和二道河硝酸盐来源主要是土壤氮和生活污水及畜禽粪便的排放.丰水期，ρ（NO3-）与ρ（NH4+）呈负相关关系，与δ15N-NO3-呈正相关关系，说明研究区域发生了氨氮的挥发和硝化过程.二道河和蓝河随着ρ（NO3-）和ρ（Cl-）降低，ρ（NH4+）和δ15N-NO3-增加，说明有明显的反硝化过程发生.不同采样期NO3-和Cl-呈显著正相关关系，表明各采样河流均发生了混合过程.研究结论为丘陵地区硝酸盐来源的季节差异分析提供参考. |
| 英文摘要 |
| This study analyzed the nitrate (NO3-), ammonia nitrogen (NH4+-N), chloride (Cl-), δ15 N-NO3-, δ18O-NO3-, and δ18O-H2O in the surface water to identify the nitrate sources and transformation processes in midstream areas of the Taizi River basin in May and August 2016, corresponding to the dry season and wet season, respectively. The results indicated that the NO3-, Cl-, and NH4+-N concentrations and the δ18O-NO3- in the dry season were greater than those in the wet season, and the δ15 N-NO3- did not show significant seasonal variations based on the Man-Whitney U test. The NO3- was derived mainly from the mixed sources according to the ranges of NO3-/Cl-, δ15 N-NO3-, and δ18O-NO3-. The nitrate sources in the surface water were synthetic fertilizer, soil nitrogen, manure, and sewage in the Xihe River (XR), Lanhe River (LR), and Xiada River (XDR) and soil nitrogen and synthetic fertilizer in the Er dao River (EDR) during the wet season. The sources were synthetic fertilizer and soil nitrogen in the XDR and soil nitrogen, manure, and sewage in the XR, LR, and EDR during the dry season. The significant negative relationship between NO3- and NH4+ and the significant positive relationship between NO3- and δ15 N-NO3- in the wet season indicated that the volatilization and nitrification of soil N might be related to NO3- sources in the wet season. NH4+-N and δ15 N-NO3- increased with decreasing NO3- and Cl- in EDR and LR during the wet season, which indicated denitrification processes occurred. There was a significant relationship between NO3- and Cl-, indicating that mixing processes occurred in the surface water during the two sampling periods. This study will provide a better understanding for nitrate sources related to seasonal variations and transformation processes in hilly areas. |
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