Temporal and Spatial Variations of Total Nitrogen and Total Phosphorus in the Typical Reaches of Qinhuai River
秦淮河典型河段总氮总磷时空变异特征

The year-round concentrations of total nitrogen (TN) and total phosphorus(TP) were monitored from June 2010 to May 2011 in the typical reaches of the Qinhuai River. The spatial and temporal variations in TN and TP concentrations and the pollution status of the river water were investigated using typical statistics analysis. Results showed that the river water was seriously polluted in terms of TN and TP, and that the concentrations of both TN and TP showed high spatial and temporal variations. The average TN concentrations of the river water in the traditionally managed agricultural area, intensively managed agricultural area, and urban area were 1.80, 3.97 and 9.25 mg·L-1, respectively; The corresponding average TP concentrations were 0.03, 0.11 and 0.50 mg·L-1, respectively, showing similar spatial patterns with those of TN. The spatial variations in TN and TP concentrations in river water indicated that the urban area and intensively managed agricultural area,rather than the traditionally managed agricultural area,were the major sources for TN and TP in the river water. The average TN concentrations of river water during the wet season and dry season were 1.89 and 4.58 mg·L-1, respectively; and the corresponding average TP concentrations were 0.11 and 0.14 mg·L-1,respectively. The temporal variations indicated that the pollution status of the river water was more serious during the dry season than that during the wet season. Assessment results of eutrophication indicated that the majority of Qinhuai River reaches were in the stage of eutrophication, thus deserving immediate controlling measures.