Analysis of“Three Nitrogen”pollution characteristics and mechanism in shallow groundwater of Zhecheng area

By studying on pollution situation and distribution of "three nitrogen" in Zhecheng area, this paper analyzes the pollution sources、Pollution mechanism and control countermeasures. The results show that nitrate nitrogen are in limit almost, ammonia nitrogen exceeding with large area and nitrite nitrogen pollution present dotted distribution; excessive use of agricultural nitrogen fertilizer and pesticide is the main reason of shallow groundwater pollution of "three nitrogen", the second is industrial wastewater and domestic sewage discharge. Lithology and thickness of vadose zone, weakly-alkaline water are important reason why ammonia nitrogen is widely distributed.