| 汉江上游金水河流域氮湿沉降 |
| 摘要点击 2790 全文点击 1374 投稿时间：2013-04-07 修订日期：2013-07-05 |
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| 中文关键词 金水河流域 氮湿沉降 氮截留 源头河流 氮负荷 |
| 英文关键词 Jinshui watershed wet deposition of atmospheric nitrogen nitrogen retention head watershed N loading |
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| 中文摘要 |
| 汉江上游金水河流域是南水北调工程的重要水源涵养区，但是氮污染已成为该流域水质的主要威胁因素. 该研究对汉江的金水河流域开展了为期1 a（2012-02~2013-02）的氮湿沉降观测，并利用氮输出模型估算了氮湿沉降对河流氮负荷的贡献量. 结果表明雨水中总氮（DTN）的浓度在0.24~2.89 mg·L-1之间，铵态氮（NH4+-N）、硝态氮（NO3-N）及有机氮（DON）分别占42.8%、13.3%和43.9%；雨水氮浓度随降雨量增大而变小，明显受到降雨的稀释作用. 流域内氮湿沉降主要来自人类活动，沉降负荷在4.97~7.00 kg·（hm2·a）-1之间，受降雨量的主要影响，上游地区的氮湿沉降负荷>下游地区>中游地区，春夏两季约占全年氮湿沉降的81%. 流域氮湿沉降对河流氮负荷贡献量约为34000~46000 kg，只占流域氮肥贡献量的5.05%~6.78%，远小于流域内农业活动化肥氮的贡献量，不是河流氮的主要来源. |
| 英文摘要 |
| The Jinshui River, a tributary of the Hanjiang River, is an important region of water conservation for the Middle Route of South to North Water Transfer Project. However, water quality has been deteriorated in recent years, in particular nitrogen increasing pollution. In this study, the wet deposition of atmospheric nitrogen in the Jinshui watershed was investigated between Feb. 2012-Feb. 2013, and the corresponding contribution to the river N loading was calculated using N retention model. The results indicated that the volume-weighted concentration of dissolved total nitrogen (DTN) was 0.24-2.89 mg·L-1, consisting of ammonium (NH4+-N)(42.8%), nitrate (NO3-N)(13.3%) and dissolved organic nitrogen (DON)(43.9%), which decreased with rainfall volume as a result of dilution. The wet deposition of atmospheric N was mainly from anthropogenic pollution and the flux was between 4.97-7.00 kg·(hm2·a)-1, dominated by seasonal rainfall, of which about 81% occurred in spring and summer and the flux in a decreasing order of upstream, downstream, and middlestream. The wet deposition contributed approximately 34000-46000 kg N to the river, accounting for only 5.05%-6.78% of the contribution by fertilizers, which was too small to be the main source of the river N loading. |
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