| 澜沧江水系氮磷污染及硝酸盐来源解析 |
| 摘要点击 3414 全文点击 1873 投稿时间：2021-12-19 修订日期：2022-03-30 |
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| 中文关键词 澜沧江流域 NO3--N 氮同位素 氧同位素 来源解析 |
| 英文关键词 Lancang River Basin NO3--N nitrogen isotope oxygen isotope source apportionment |
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| 中文摘要 |
| 有效控制氮磷输入是水质持续改善的关键因素.为识别澜沧江水系水体中氮磷浓度、氮污染物来源及其空间分布特征，在澜沧江流域开展了干流和支流水样的采集，分析流域不同区域水体氮磷浓度，并利用氮氧同位素技术结合稳定同位素SIAR模型，解析了水系不同区域氮素来源及其贡献率.结果表明：①澜沧江水系氮浓度偏低，ρ（TN）分布在0.34~4.18 mg·L-1之间，从上游至下游有升高趋势；ρ（TP）分布在0.11~2.34 mg·L-1之间.②澜沧江水系的δ15 N-NO3-和δ18 O-NO3-值分别分布在-5‰~5‰和-16‰~16‰之间，主要落在降雨及肥料和土壤氮范围内，主要存在硝化作用.③澜沧江干流中土壤氮和化学肥料的贡献率分别为37.67%~42.41%和34.22%~38.56%，粪便和生活污水占15.01%~20.79%，大气沉降仅占4.49%~7.32%.中游支流和下游支流中土壤氮的贡献明显高于化学肥料，土壤氮的贡献率达53.97%~61.57%，化学肥料占33.37%~38.30%，而大气沉降、粪便和生活污水的贡献率较低.研究分析了澜沧江水系上、中和下游干流和支流的氮素来源，为该区域的水质管理和污染源治理提供了依据. |
| 英文摘要 |
| The effective control of nitrogen (N) and phosphorus (P) input is a key factor in the improvement of water quality. In order to identify the concentrations of N and P and the sources of N pollutants and their spatial distribution characteristics in the Lancang River, water samples of Lancang mainstream and major tributaries were collected, and the N sources and contribution rates were analyzed by using nitrogen and oxygen isotope technology combined with a stable isotope SIAR model. The results showed that:① the N concentrations in the Lancang River were low, and the TN concentrations ranged from 0.34 to 4.18 mg·L-1 and increased from upstream to downstream; the TP concentrations ranged from 0.11 to 2.34 mg·L-1. ② δ15N-NO3- and δ18O-NO3- in the Lancang River were in the range of -5‰-5‰ and -16‰-16‰, respectively, and mainly fell in the range of rainfall, fertilizer, and soil N. The nitrification process occurred mainly in the Lancang River. ③ The contribution rates of soil N and chemical fertilizer in the mainstream of the Lancang River ranged from 37.67%-42.41% and 34.22%-38.56%, respectively, manure and sewage accounted for 15.01%-20.79%, and atmospheric deposition accounted for only 4.49%-7.32%. The contribution rates of soil N of 53.97%-61.57% in tributaries in the middle and downstream reaches were higher than that of chemical fertilizer (33.37%-38.30%), whereas the contributions of atmospheric deposition and manure and sewage were low. This study analyzed the N source of the Lancang mainstream and tributaries in the upper, middle, and lower reaches, providing a theoretical basis for water quality management and pollution source control in the Lancang River basin. |
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