Li Yan-Li, Yang Zi-Rui, Yin Xi-Jie, Sun Wei
Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo 454000, China.
Open Laboratory of Ocean & Coast Environmental Geology, Third Institute of Oceanography State Administration, Xiamen 361005, China.
Huan Jing Ke Xue. 2018 Mar 8;39(3):1076-1084. doi: 10.13227/j.hjkx.201705248.
A total of 14 samples were collected in May 2016(dry season)and August 2016 (wet season) in the downstream area of the Taizi River. △ N-NO and △ O-NO were determined using the azide method, and △ O-HO was determined using a CO-HO equilibration technique. To identify NO sources and transformations in the downstream area of Taizi River Basin, ion chromatography, Nessler's reagent spectrophotometry, the azide method, and CO-HO equilibration methods were utilized to determine the concentrations of NO, Cl, NH-N, and isotopic compositions (△ N and △ O) of NO and the △ O-HO in surface water. The results showed that the NO was mainly derived from mixed sources. During the dry season, the nitrate in the surface water was derived from soil nitrogen, manure, and sewage in the upper reaches, and mainly derived from synthetic fertilizer, manure, and sewage in the middle and lower reaches of the Beisha River. The nitrate was mainly derived from manure and sewage in the Nansha River. The nitrate was mainly derived from soil nitrogen in the upper reaches, mainly derived from synthetic fertilizer, manure, and sewage in the middle reaches, and mainly derived from manure and sewage in the lower reaches of the Haicheng River. During the wet season, the nitrate sources in surface water were soil nitrogen, synthetic fertilizer, manure, and sewage in the Beisha River; synthetic fertilizer, manure, and sewage in the middle and lower reaches of the Haicheng River and the Nansha River; and soil nitrogen and synthetic fertilizer in the upper reaches of the Haicheng River. NO and NH-N concentrations decreased with increasing △ N-NO from the dry season to the wet season, indicating that volatilization of NH-N and denitrification of NO might occur during the wet season. There is a slightly positive relationship between the reciprocal of the concentration of 1/(NO) and △ N-NO during the wet season, indicating that mixing processes occurred in surface water. The results will provide information on nitrate sources during seasonal variations in the plain areas.
2016年5月（旱季）和2016年8月（雨季），在太子河下游地区共采集了14个样本。采用叠氮化物法测定△N-NO和△O-NO，采用CO-HO平衡技术测定△O-HO。为了确定太子河流域下游地区的氮氧化物来源和转化情况，利用离子色谱法、纳氏试剂分光光度法、叠氮化物法和CO-HO平衡法测定了地表水中氮氧化物、氯离子、氨氮的浓度以及氮氧化物的同位素组成（△N和△O）和△O-HO。结果表明，氮氧化物主要来源于混合源。旱季时，地表水硝酸盐来源于上游土壤氮、粪便和污水，北沙河中下游主要来源于合成肥料、粪便和污水。南沙河硝酸盐主要来源于粪便和污水。海城河硝酸盐上游主要来源于土壤氮，中游主要来源于合成肥料、粪便和污水，下游主要来源于粪便和污水。雨季时，地表水硝酸盐来源为北沙河土壤氮、合成肥料、粪便和污水；海城河中下游和南沙河合成肥料、粪便和污水；海城河上游土壤氮和合成肥料。从旱季到雨季，随着△N-NO的增加，氮氧化物和氨氮浓度降低，表明雨季可能发生氨氮挥发和氮氧化物反硝化作用。雨季时，1/(氮氧化物)浓度的倒数与△N-NO之间存在微弱的正相关关系，表明地表水中发生了混合过程。研究结果将为平原地区季节性变化期间的硝酸盐来源提供信息。
