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]