Application of Cluster Analysis and Multivariate Statistical Techniques Associated with Water Quality Index to Evaluate Water Quality of Tigris River in Iraq

Abstract

The study comprised investigation of the seasonal and spatial variations in water quality of the Tigris River in Iraq for the period (2005-2012). Cluster analysis (CA) and principal component analysis (PCA) were applied to analyze the similarities among sampling sites to identify the source apportionment of pollution parameters in river. Three principal components were extracted explaining 88.64 % of the total variance and indicating that the main components affecting water quality are soil leaching and runoff associated with dissolved ions, domestic wastewater discharge and industrial effluents from point source. In addition to the multivariate statistical techniques, water quality index (WQI) was used for the assessment of water quality through an index number. The WQI of the river for the studied period was 79.7 units classified as fair quality, which requires treatment for drinking use and no treatment for irrigation purposes.