In this paper, when certain index’s pollution contribute rate is calculated, the arithmetic average value
of the actual monitoring numbers of some certain index in every section during the monitoring period
should be calculated firstly. Then, according to the formula above, the pollution contribute rate of this
index is calculated. According to the Table 1 of the National Water Quality Standard, when certain
index’s pollution contribute rate is calculated, the arithmetic average value of the actual monitoring
numbers of some certain index in every section during the monitoring period should be calculated firstly.