An analysis of nitrogen pollution in river water of the Yellow River basin
黄河流域河水氮污染分析

A study has been carried out to analyze the monitoring data of nitrogen pollution of the Yellow River basin in 1980,1990, 1997 and 1999.The results indicate as follows: (1)The nitrogen content of the tributaries showed an increasing trend from the upper basin to the lower basin of the Yellow River, which led to the increasing trend of nitrogen concentration of the mainstream from the upper reaches to the lower reaches; (2)Nitrogen in the river water of the mainstream and the tributaries of the Yellow River was mainly attributed to point source. The ratio of point to non point sources decreased from 2.7 in 1990 to 1.8 in 1997 for total nitrogen of river water at Tongguan Station; (3) The ammonium nitrogen content of river water showed an accelerated increasing trend in the mainstream and the tributaries during 1980-1990-1999, which was caused by the increase of waste water discharge and nitrogenous fertilizer application in the Yellow River basin.