丹江口水库流域氮素时空分布特征

The Temporal and Spatial Distribution of Nitrogen in Danjiangkou Reservoir Watershed

为全面了解丹江口水库流域氮素污染状况,对库区26个点位及10条主要入库河流入库口处的表层水样进行了丰水期、平水期、枯水期采样与监测,探讨了氮素时空分布特征。入库口总氮检出范围为1.31－10.96 mg/L,其中泗河和神定河入库口总氮最高。总氮为库区水质主要限制因子,年均总氮质量浓度为1.13－2.71 mg/L;汉江库区整体上总氮污染水平略高于丹江库区,且与丹江库区相比,汉江库区受点源排放的影响较大。10条入库河流总氮的总年均输入量为63 347.31 t/a,其中汉江的总氮输入量最大;入库河流总氮控制的关键在于溶解性有机氮和硝酸盐氮的控制。

In order to investigate the pollution characteristic of nitrogen in Danjiangkou Reservoir watershed,surface water at 26 sampling sites in the reservoir area and 10 sampling sites in the main tributaries were collected and analyzed in different seasons.The concentrations of total nitrogen（ TN） are in the range of 1. 31- 10. 96 mg / L for the main tributaries,and the concentrations of TN in Sihe River and Shendinghe River are obviously higher than that in other rivers. TN is the limit factor for the water quality in Danjiangkou Reservoir,and the annual average concentration of TN is 1. 13- 2. 71 mg / L. Generally,the concentration of TN in the reservoir area in Hanjiang watershed（ HK） is higher than that in the reservoir area in Danjiang watershed（ DK）,and compared with DK,the HK is strongly influenced by the discharge of point sources. The annual average input amount of TN from10 tributaries is 63 347. 31 t,and among the 10 tributaries,Hanjiang River has a biggest contribution for inputting of TN. The result of nitrogen forms analysis shows that the key to control TN in tributaries is to control the input of dissolved organic nitrogen（ DON） and nitrate-nitrogen.