Wang Shuo, Zhi Wei, Li Shengjie, Lyu Tao, Ji Guodong
Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China.
The National Key Laboratory of Water Disaster Prevention, Yangtze Institute for Conservation and Development, Key Laboratory of Hydrologic-Cycle and Hydrodynamic-System of Ministry of Water Resources, College of Hydrology and Water Resources, Hohai University, Nanjing 210024, China.
Natl Sci Rev. 2024 Dec 11;12(2):nwae458. doi: 10.1093/nsr/nwae458. eCollection 2025 Feb.
The riverine NO fluxes are assumed to linearly increase with nitrate loading. However, this linear relationship with a uniform EF is poorly constrained, which impedes the NO estimation and mitigation. Our meta-analysis discovered a universal NO emission baseline (EF = k/[NO ], k = 0.02) for natural rivers. Anthropogenic impacts caused an overall increase in baselines and the emergence of hotspots, which constitute two typical patterns of anthropogenic sources. The k values of agricultural and urban rivers increased to 0.09 and 0.05, respectively, with 11% and 14% of points becoming NO hotspots. Priority control of organic and NH pollution could eliminate hotspots and reduce emissions by 51.6% and 63.7%, respectively. Further restoration of baseline emissions on nitrate removal is a long-term challenge considering population growth and declining unit benefits (ΔN-NO/N-NO ). The discovery of EF lines emphasized the importance of targeting hotspots and managing baseline emissions sustainably to balance social and environmental benefits.
河流中一氧化氮（NO）通量被假定为随硝酸盐负荷呈线性增加。然而，这种具有统一排放因子（EF）的线性关系受到的约束较弱，这阻碍了对NO的估算和减排。我们的荟萃分析发现了天然河流的普遍NO排放基线（EF = k/[NO]，k = 0.02）。人为影响导致基线总体上升和热点出现，这构成了人为源的两种典型模式。农业河流和城市河流的k值分别增至0.09和0.05，分别有11%和14%的点成为NO热点。优先控制有机和NH污染可消除热点，并分别将排放量降低51.6%和63.7%。考虑到人口增长和单位效益下降（ΔN-NO/N-NO），进一步恢复硝酸盐去除的基线排放是一项长期挑战。排放因子线的发现强调了针对热点并可持续管理基线排放以平衡社会和环境效益的重要性。
