Table 1 Evaluation criteria for the single-factor pollution index and the Nemerow pollution index.
Water quality level | Pi | Pollution assessment | PN | Pollution assessment |
|---|---|---|---|---|
I | ≤ 1 | No pollution | <0.59 | No pollution |
II | (1,2] | Slightly pollution | [0.59,0.74) | Slightly pollution |
III | (2,3] | Lightly pollution | [0.74,1.00) | Lightly pollution |
IV | (3,5] | Moderately polluted | [1.00,3.50) | Moderately polluted |
V | >5 | Seriously pollution | ≥ 3.50 | Seriously pollution |
