1996-2009年渭河干流氮素污染特征

通过对渭河干流华县站1996-2009年氮浓度与流量监测数据进行分析,探讨了渭河流域氮素污染特征。结果表明:(1)氨氮、亚硝氮和硝氮的年平均浓度在研究年内呈减小趋势,分别从1996-2000年的7.31,0.74和2.25 mg/L,减小到2001-2009年的6.88,0.71和1.99 mg/L;总氮年均浓度与年均负荷1996-2006年总的趋势是减小;(2)研究年内氮素年平均浓度为:氨氮>硝氮>亚硝氮;(3)枯水期氨氮浓度均高于平水期和丰水期,可能是河流径流量少和流域废污水增加所致;(4) 1996-2006年氮污染的点源贡献都呈现减小趋势,非点源污染贡献呈上升趋势,并且总体上非点源污染贡献突出。

Nitrogen Pollution of Weihe River During 1996-2009

Through analyzing the nitrogen concentration and the flow at hydrologic station of Huaxian County during 1996-2009, the characteristics of nitrogen pollution in Weihe River were discussed. The results showed that:(1) The annual mean concentration of ammonia, nitrite and nitrate decreased in the study years from 7.31 mg/L, 0.74 mg/L and 2.25 mg/L during 1996-2000 to 6.88 mg/L, 0.71 mg/L and 1.99 mg/L during 2001-2006, the average concentration of total nitrogen was also decreased.(2) The magnitude of the nitrogen average concentration in Weihe River was:ammonia >nitrite >nitrate.(3) The concentration of ammonia in the dry season was higher than that in wet and normal seasons, which was due to the decrease of flow and the increase of waste water in the Weihe River basin.(4) The point source pollution load proportion of the nitrogen pollution decreased and the non-point source pollution load proportion increased, and the general trend was that the non-point source pollution load proportion increased strikingly from 1996 to 2006.