Index Values | Equation/Class | References |
Geoaccumulation index | Igeo = log2[Cn/(1.5 × Bn)] | [43] |
Igeo < 0 | Unpolluted | [44] |
0 < Igeo < 1 | Unpolluted to moderately polluted | [45] |
1 < Igeo < 2 | Moderately polluted | [35] |
2 < Igeo < 3 | Moderately to strongly polluted | [32] |
3 < Igeo < 4 | Strongly polluted | [34] |
4 < Igeo < 5 | Strongly polluted to extremely polluted | |
Igeo > 5 | Extremely polluted | |
Pollution load index | PLI= | [44] |
P.L.I. < 1 | Unpolluted | [45] |
1 < P.L.I. < 2 | Moderately polluted | [46] |
2 < P.L.I. < 10 | Strongly polluted | [34] |
P.L.I. > 10 | Extremely polluted | [35] |
Risk Index | [47] | |
RI < 150 | Low ecological risk | [31] |
150 < RI < 300 | Moderate ecological risk | [48] |
300 < RI < 600 | Significant ecological risk | [35] |
RI > 600 | Very high ecological risk | [27] |