Comprehensive pollution index P value range water quality classification basis is ≦0.20. Most items are not checked out, but some items are checked out within the standard range. 0.2 1 ~ 0.40 is within the standard range, and some items are close to or exceed the standard. 0.4 1 ~ 0.70 is light pollution, and individual items were detected and exceeded 0.7 1 ~ 1.00.

The water quality index proposed by Boren of Beiguan in 1974 to evaluate water pollution under the influence of various pollutants. It is the first comprehensive indicator of water pollution in China. Its expression is: K = where: k is the comprehensive pollution index; Ck is the highest allowable standard of surface water pollutants according to the specific situation. Coi is the highest allowable standard of various pollutants in surface water; Ci is the concentration of various pollutants in surface water. The comprehensive pollution index is expected to use the simplest statistical value to evaluate the water pollution situation. The water pollution degree of different river sections can be compared in space, which is convenient for classification. In time, it can represent the general trend of water pollution in a river reach and a region; It improves the deficiency of single index in comprehensive characterization of water pollution; It solves the difficulties of calculation, comparison and comprehensive evaluation when describing water pollution with multiple indicators. It also overcomes the shortcoming that it is not easy to give concise quantitative values when evaluating water pollution with biological indicators. K is different from the general water quality index that represents the physical and chemical properties of water quality. When selecting water quality parameters, priority should be given to important harmful substances that cause water pollution.