Institute of Resources & Environment, Henan Polytechnic University, Jiaozuo, 454003, China.
Institute of Resources & Environment, Henan Polytechnic University, Jiaozuo, 454003, China.
Environ Pollut. 2024 Jan 15;341:122906. doi: 10.1016/j.envpol.2023.122906. Epub 2023 Nov 10.
Dissolved organic nitrogen (DON) deposition was the substantial component of dissolved total nitrogen (DTN) deposition in the world's nitrogen deposition hot spots areas. However, the information on the importance for DON deposition and its sources was still scarce, which limited the comprehensive assessment of the ecological threat from nitrogen deposition. Six sampling sites around the Danjiangkou Reservoir were set up to collect the dry and wet deposition samples from October 2017 to September 2021. The results showed that dry and wet DTN deposition averaged 34.72 kg ha yr and 22.27 kg ha yr, respectively. Dry NH-N, NO-N and DON deposition averaged 14.28 kg ha yr, 5.91 kg ha yr and 14.53 kg ha yr, respectively. Wet NH-N, NO-N and DON deposition averaged 11.14 kg ha yr, 3.89 kg ha yrand 7.24 kg ha yr, respectively. The contributions of DON to DTN were 41.85% (in dry deposition) and 32.50% (in wet deposition), respectively. Dry DON deposition varied between 26.44 kg ha yr and 9.11 kg ha yr, and significantly differed among six sampling sites (P < 0.05). The different intensity of agricultural activities disturbance at the sampling sites was the important reason for the spatial variations of DON deposition. DON deposition was significantly correlated with ammonium nitrogen (NH-N) deposition (P < 0.05). According to the results of positive matrix factorization (PMF) model, agriculture source contributed significantly to the DON deposition, the contributions at six sampling sites ranged from 45.8% to 73.7% in dry deposition, and from 56.8% to 81.6% in wet deposition. In summary, our findings found that agricultural activities were the important factors influencing the spatial patterns of DON deposition around Danjiangkou Reservoir and provided new evidence for the anthropogenic source of DON deposition in China.
溶解有机氮（DON）沉降是世界氮沉降热点地区溶解总氮（DTN）沉降的主要组成部分。然而，关于 DON 沉降及其来源的重要性的信息仍然很少，这限制了对氮沉降带来的生态威胁的全面评估。在丹江口水库周围设置了六个采样点，从 2017 年 10 月到 2021 年 9 月采集干、湿沉降样品。结果表明，干、湿 DTN 沉降量分别为 34.72kg·ha-1·yr-1和 22.27kg·ha-1·yr-1。干沉降 NH-N、NO-N 和 DON 沉降量分别为 14.28kg·ha-1·yr-1、5.91kg·ha-1·yr-1和 14.53kg·ha-1·yr-1。湿沉降 NH-N、NO-N 和 DON 沉降量分别为 11.14kg·ha-1·yr-1、3.89kg·ha-1·yr-1和 7.24kg·ha-1·yr-1。DON 对 DTN 的贡献分别为 41.85%（干沉降）和 32.50%（湿沉降）。干 DON 沉降量在 26.44kg·ha-1·yr-1至 9.11kg·ha-1·yr-1之间变化，在六个采样点之间差异显著（P<0.05）。采样点农业活动干扰的不同强度是 DON 沉降空间变化的重要原因。DON 沉降与铵态氮（NH-N）沉降显著相关（P<0.05）。根据正定矩阵因子（PMF）模型的结果，农业源对 DON 沉降的贡献显著，六个采样点的干沉降贡献范围为 45.8%至 73.7%，湿沉降贡献范围为 56.8%至 81.6%。综上所述，我们的研究结果发现，农业活动是影响丹江口水库周围 DON 沉降空间格局的重要因素，为中国 DON 沉降的人为来源提供了新的证据。
