北方典型干旱缺水型河流氮磷时空分布特征与富营养化评价

以北方典型干旱缺水型河流-滏阳河流域邢台段为研究对象,通过为期1年(2013年6月—2014年5月)的水质监测,阐述了流域内氮磷时空变化特征及富营养化水平。结果表明,流域内水体TN的平均质量浓度为28.27 mg·L-1(其中NH4+-N占67.94%),TP的平均质量浓度为1.37 mg·L-1(其中SRP占62.01%);流域内氮磷时空分布特征明显:在时间尺度上,水体中氮磷浓度均呈现出旱季(9月—次年5月)高于雨季(6—8月);空间尺度上,氮磷质量浓度分布差异明显且均呈现出市区流域高于市郊流域,沿河流流向逐渐减少的趋势;对数型幂函数普适指数公式对水体富营养化的评价结果显示:无论从时间尺度上还是空间尺度上,所有采样点都处于极富营养状态,其变化趋势与氮磷有明显的一致性,同时富营养化程度与地区污染水平呈现一定的相关性。水资源匮乏以及河流湖库化严重是造成该地区水体富营养化问题突出的主要原因。

Temporal and spatial variation of nitrogen and phosphorus and eutrophication assessment in typical arid river in northern China

Based on a year-long(June 2013 to May 2014) water-quality survey in a typical arid river in the northern China-Xingtai segment of the Fuyang River basin,the variation features of inorganic nitrogen(N) and phosphorus(P) were analyzed.Additionally,the degree of water eutrophication of this segment was assessed.The results showed that the average concentration of TN was 28.27 mg·L-1(NH4+-N,67.94%) and the average concentration of TP was 1.37 mg·L-1(SRP,62.01%).The temporal and spatial variation of N and P in this segment was therefore quite obvious.On a timescale,the concentrations of N and P during the arid season(September to May) were higher than were those during the rainy season(June to August).At a spatial scale,the concentrations of N and P showed the same trend,with the city segment being higher compared with the suburbs,as well as being lower along the river flow.The degree of water eutrophication of this segment was extremely high at the temporal and spatial scales,and the variation trend had an obvious tendency with nitrogen and phosphorus.To some extent in certain segments,the eutrophication degree had a positive relation with the contamination.The lack of water and the steady state of the stream are the main reasons for the prominent eutrophication in this segment.