摘要
选取太子河中游地区为研究对象,联合硝酸盐(NO_3^-)、氯离子(Cl^-)、硝酸盐氮、氧同位素(δ^(15)N和δ^(18)O)和水的氧同位素(δ^(18)O)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ManWhitney U检验,枯水期ρ(Cl^-)、ρ(NO_3^-)、ρ(NH_4^+-N)和δ^(18)O-NO_3^-显著高于丰水期,δ^(15)N-NO_3^-无显著时间差异.根据NO_3^-/Cl^-,δ^(15)N-NO_3^-和δ^(18)O-NO_3^-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(NO_3^-)与ρ(NH_4^+)呈负相关关系,与δ^(15)N-NO_3^-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(NO_3^-)和ρ(Cl^-)降低,ρ(NH_4^+)和δ^(15)N-NO_3^-增加,说明有明显的反硝化过程发生.不同采样期NO_3^-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.
This study analyzed the nitrate （NO -3 ）, ammonia nitrogen （NH ＋4 -N）, chloride （Cl - ）, δ15N-NO -3 , δ18O-NO -3 , and δ18O-H2 O 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 NO -3 , Cl - , and NH ＋4 -N concentrations and the δ18O-NO -3 in the dry season were greater than those in the wet season, and the δ15N-NO -3 did not show significant seasonal variations based on the Man-Whitney U test. The NO -3 was derived mainly from the mixed sources according to the ranges of NO -3 / Cl - , δ15N-NO -3 , and δ18O-NO -3 . 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 NO -3 and NH ＋4 and the significant positive relationship between NO -3 and δ15N-NO -3 in the wet season indicated that the volatilization and nitrification of soil N might be related to NO -3 sources in the wet season. NH ＋4 -N and δ15N-NO -3 increased with decreasing NO -3 and Cl - in EDR and LR during the wet season, which indicated denitrification processes occurred. There was a significant relationship between NO -3 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.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2017年第12期5039-5046,共8页
Environmental Science
基金
国家自然科学基金项目(41401029)
河南省博士后经费项目
河南理工大学青年骨干教师项目
