SURFACE WATER QUALITY ASSESSMENT USING MULTIVARIATE STATISTICAL TECHNIQUES: A CASE STUDY OF SHAYING RIVER BASIN (LOWER REACH), CHINA

摘要

The surface water quality of the lower reach of Shay-ing River Basin (SRB) was assessed based on chemical analysis of 13 parameters in 15 sampling sites along the river during 2008 to 2010. According to the surface water standards of China (GB3838-2002), the water quality of all 15 sites was worse than Class V mainly due to the presence of ammonia nitrogen (NH_3-N) and total nitrate (TN). Multivariate statistical techniques were applied to characterize the water quality in the study area. Ordination diagram of correspondence analysis demonstrated that Sites 3 and 5 were the most affected by NH_3-N and TN. The sites located downstream of Fuyang City were found to be heavily polluted due to wastewater discharge from industry and domestic sewers. Three factors were identified by principal component analysis, representing 95.33% of the total variation. The first factor (PCI) captures variables of PI, BOD, NH_3-N, COD, TN, F and S. The second factor (PC2) is significantly related to Oil and total coliform, with total phosphorus accounting for the greatest loading for Factor 3 (PC3). Hierarchical cluster analysis showed that the sites were divided into several groups: two for PC1, three for PC2, and three for PC3. BOD, NH_3-N, and TN were the priority pollutants identified in the wastewater from SRB (lower reach). These priority pollutants should be reduced and purified before being discharged into rivers and a more comprehensive water quality monitoring network should be also established across the SRB as soon as possible.