Establishment of Identification Pollution Function Index and Its Application in Water Quality Assessment of Hanjiang River

In order to accurately measure the water quality of Ankang section of the Hanjiang River, based on the deterministic method of the water quality evaluation, the methods of the Identification Pollution Function Index based on Water Quality Standard for Fisheries (GB 11607-1989), and the Pollution Index based on the Environmental Quality Standards for Surface Water (GB 3838-2002) were constructed respectively, and the measurement results compared. The results showed that the water quality of Ankang section of the Hanjiang River is Grade Ⅱ of surface water and suitable for fishing, being slightly polluted by N and P. The results derived from the Identification Pollution Function Index were strongly consistent with those from Overlaying Pollution Index, Arithmetic-average Pollution Index and Nemerow Pollution Index, and are able to accurately express the quality and functions of water body and to compare the water quality among different water bodies. The Identification Pollution Function Index can be used as evaluation index for the water body of the Hanjiang River.