典型城市河段中水体的氮磷形态变化影响因子研究

Study on Influencing Factors of Nitrogen and Phosphorus Migration and Transformation in Typical Urban Scenic River

以太湖流域某城市为研究对象,针对城市不同类型河段底泥氮磷释放的问题,通过对河段水质和沉积物的长期观测,并运用单因子和地累积指数法分析评价该地区沉积物的污染现状,发现水体中COD等受季节变化的影响存在相似时空变化规律;河道沉积物中的总氮、总磷和有机质数值均超出本底值,钙、铁、锰在此区域处于低污染等级;TN、总磷、硝氮/氨氮是影响氮磷之间形态变化的关键因子;沉积物中氮磷变化易受水质中总氮、氨氮、硝态氮浓度的影响,钙、铁等是导致沉积物释放营养盐的关键。

In order to explore the key factors affecting the release of nitrogen and phosphorus from different types of river sediment, we used single factor single factor index method and geo-accumulation index method to analyzed and evaluated the current situation of sediment pollution in the city of Taihu Lakebasin. The results showed that COD were affected by seasonal changes in three different river segments having similar spatio-temporal variation laws.;the values of total nitrogen, total phosphorus and organic matter in river sediments exceed the background values, Calcium, iron and manganese were in the low pollution level in this area;TP, TN and nitrogen-ammoniac-nitrogen ratio were the key factors affecting the migration and transformation of nitrogen and phosphorus in the reclaimed water;the change of nitrogen and phosphorus in sediment was easily affected by the concentration of total nitrogen, ammonia nitrogen and nitrate nitrogen in water. Calcium and iron were the important factors affected nutrientsand phosphorus released in sediment.