Study on Water Quality Assessment of Urban River

The paper presents the principle and calculation process of the principal component analysis which is a useful method of water quality assessment. Eight indicators include dissolved oxygen, permanganate index, BOD, ammonia nitrogen, copper, zinc, volatile phenol, oil in 20 monitoring sections of Ningbo urban river were analyzed by using principal component analysis. Three factors with 86.67% of accumulated contribution rates were extracted from the original data, which include organic matter factor, heavy metal matter factor, ammonia nitrogen and volatile phenol factor. The results show that 50% water sections can´t reach the standards, most of them located in Yinzhou River, Yin River and Fenghua River. The results consist with the actual situation.