In the formula, K j——the share ratio of i units pollution out of j sections’ total pollutions;
Pj ——the omnibus index of j sections’ water contamination;
Pij——the pullulated indicator of i units pollution in j section;
Cij ——the average value of i units pollution in j section;
Ci0——the V standard value of i units pollutions in GB3838-2002;
n ——the units of pollutions which involved in the evaluation.