[Input Characteristics and Pollution Assessment of Nutrients Pollution in the Primary Pollution Source of the Daliao River].

A total of 13 surface water samples were collected from sewage outfalls and 3 main tributaries ( Hunhe River, Taizi River and Haicheng River) of the Daliao River to clarify the pollution characteristics of various species of nitrogen and phosphorus in July 2013, respectively. The results showed that the concentrations of DON in the Hunhe River, NO3(-)-N in the Taizi River, NH4(+) -N, PO4(3-) -P and DOP in the Haicheng River were higher than others. In water samples from the 3 main tributaries of the Daliao River, the TN and TP contents were above the national environmental quality standards for surface water (GB 3838-2002, grade V) except for the TP that was classified as grade IV in the Taizi River. The percentages of various N species showed that NO3(-) -N was the major N species in the Taizi River and Haicheng River, meanwhile DON was the major N species in the Hunhe River. The percentages of various P species showed that TPP was the major P species in the Hunhe River and Taizi River, and DOP was the major P species in the Haicheng River. TN content was above the national environmental quality standards for surface water (GB 3838-2002, grade V) in sewage outfalls. But TP content was classified as grade IV to above grade V. And the concentrations of NH4(+) -N, TN and TP in sewage outfalls of Shachang and Gangjian were higher than those in other sewage outfalls. The percentages of various N species in sewage outfalls showed that DIN was the major N species in sewage outfalls. There were higher level of TN and TP content in the Daliao River than those of tribtaries, and NO3(-) -N and TPP were the major N and P species, respectively. In general, the nutrients analysis of tributaries, sewage outfalls and the Daliao River showed that nutrients of the Daliao River were affected by sewage outfalls. And the effect was significant and non-ignorable.