Abstract
In this report, first of all, the method to deduce the biological class (saprobic zone) from physical and chemical items of water quality of rivers was developed. Then, the synthetic evaluation of water quality or water pollution level of rivers from both the physical and chemical indexes and the biological index was done by the principal component analysis method (PCA). The first principal component of PCA was proved to be available for the evaluation of water quality or water pollution level of rivers. Using the physical and chemical variables and the biological variable duduced by the manner described above, the synthetic evaluation of water quality of rivers was done by PCA, and the first principal component was found to be the same factor as mentioned above.
