There is some numerical classification based on quantitative estimation of organisms which is present in the water, based on the index values

 Dear Dr.kani

please if you know , introduce reference.

thanks

You can use AMBI or M-AMBI index instead of Shanon index. Actually both these two index calculate base of Shanon and Richness index and can group polluted area and  give you ecological status

Mohammad

Dear Gerami

Is it apply on plankton community ?

Could you please introduce its reference ?

Thanks

Mahnaz

if you work with DNA, then allele frequency and genetic distance (Fst and Gst values) can be used as index for population differentiation.

Thank you so much for your answer, but my question is about the recognize the pollution level on the base of Shannon index.

I think the Ebrahimnezhad suggestion  is perfect.

thanks all