Hello,

I send you one link to one original paper, there you can find some answers, but it is Slovak language, you need to use google traslator or citations below the text. Try, maybe it could help you. Sincerely Andrea.J.

http://www.vuvh.sk/download/kniznica/zborniky/zb_hydrochemia12/27.pdf

It seems really a big question, many scientist fighting for  a long time to find useful biological  indicators for water pollution. And anyone cannot solve it in  a few words.   Usually, assessment of River Water Quality Using Macroinvertebrate Organisms as Pollution Indicators, due to its  stability, bioaccumulation and easy collectted.   You can find a sample in the follow paper:

Assessment of River Water Quality Using Macroinvertebrate Organisms as Pollution Indicators of Tamirabarani River Basin, Tamil Nadu, India

International Journal of Environmental Protection(IJEP)

ISSN: 2226-6437(Print)

inaddition, there are some other information in the follow website, hope its useful. http://isww.iwg.kit.edu/607_1717.php

De nombreuses études ont été réalisées sur ce thème et les principaux organismes utilisés comme indicateurs de qualité des eaux et particulièrement de pollution tels que : les macroinvertébrés benthiques (www.onema.fr/IMG/pdf/bioindication-outils-d-evaluation.pdf ; https://books.google.fr/books?isbn=148318188X ) ; les algues et les macrophytes (journals.cambridge.org/article_S0003408893000214 ; acces.ens-lyon.fr/.../les-diatomees-bio-indicatrices-de-la-qualite-des-cours d'eau ; www.documentation.eaufrance.fr/.../les-macrophytes-aquatiques-bioindicateurs

Daer kani,

Measurements of Water Quality parameters, assessing the presence of heavy metals (eg. Hg, Pb, Cd etc) in various macro-invertebrates (snails, clam, oyster, mussels, zoo plankton or even  benthic polychate worms also) as they functioning in bio-accumulation process (often filter the pollutants) that considered them pollution Indicators organisms in many parts of the Globe.

Many phytoplankton species are also helpful as bioindicators; Diatoms in particular can be useful.

http://cdn.intechopen.com/pdfs-wm/36803.pdf

Biological pollution indicators elucidate continuous ecological changes of an aquatic ecosystem. 

Please check the attached files for further reading.

Thank you so much for your valuable additions towards the question; i will be back to you after go through the things. 

A variety of organisms have been used in the literature as indicated in other responses. Clearly a common feature is a decline in biodiversity. We have seen this in algal populations (Algal Index) and molluscs are a very good static indicator and serve as excellent indicators of heavy metal pollution with age.

What I would like to contribute to the discussion is to point out that it will very much depend on the stream.  A stream that is in an area, largely unaffected by human activity will likely have a stable, natural ecosystem that can be monitored for changes as development takes place.  The other extreme would be a river flowing through a large city that has existed for hundreds, or thousands, of years.  In a case such as the latter, the living things that are inhabiting the stream are likely opportunistic creatures that are exploiting the current conditions to which they are adapted, but to which other creatures are not as well adapted.  In this type of circumstance one would need to understand the environmental tolerances of both the creatures that are present as well as the creatures that are absent to do an assessment of current condition of the stream.  If a specific pollutant it of concern, the best approach might be to identify an organism that is otherwise adapted to the stream's conditions but that is extremely sensitive to the pollutant of interest.

Daer kani,

I addition of my previously added answer concerning biological pollution indicators in stream or river, I am soley aggree with the answer of Eugenia López López. 

Anyway, sincere thanks to Eugenia López López for putting the answer.

Macro benthic invertabrates can be very useful in the asseement of long term pollution it is sophisticated process but one I find veryi Intriguing. With this method one can dectect the impact of very low but chronic effects on the receiving water quality by the invertabrate specieis composition and number.

Traditional indicators a fecal bacteria contamination, concentration of dissolved oxygen,etc are routinely used.

Check out the Ecology website. We have many publications available in PDF that might prove very useful.                http://www.ecy.wa.gov/

Biological indicators are aquatic plant and animal life that are susceptible to specific types and levels of pollutants. Many organisms require a specific range of physical and chemical parameters to flourish in a surface water.

I work for farmers assessing their impact on streams.  Measuring the discharge point of a drain flowing from a farm and comparing the result with Regional Council thresholds is easy.  But few farms have easily identifiable drains.  Therefore, I sample up upstream and downstream in streams that pass through or along farm boundaries and compare the differences with Regional Council Limits.  Does the stream meet the Limit or if it doesn't, is the concentration increasing - bad, stable - minor impact, decreasing - good.  So it is important that what is measured is effected locally.  I measure, Turbidity, Dissolved Reactive Phosphorous, Nitrite+Nitrate=NNN, Ammonium, Urea, and E. coli.  I use Urea as an indicator of E. coli from stock or dairy shed waste rather than waterfowl.

Measurements of Water Quality parameters, assessing the presence of heavy metals (eg. Hg, Pb, Cd etc) in various macro-invertebrates (snails, clam, oyster, mussels, zoo plankton or even  benthic polychate worms also) as they functioning in bio-accumulation process (often filter the pollutants) that considered them pollution Indicators organisms in many parts of the Globe.

Fish is useful to identify many types of pollutant as the bioaccumulation take place. Fish will provide long term effect of pollution as the lifespan of fish is long than macroinvertebrates Many researcher have found significant amount heavy metal in fish tissue exceeding food law limit. 

Good question.... There are various groups of aquatic organisms that have been used as biological indicators. Particularly pollution indicators could be macroinvertebrates as: chironomids, oligochaetes and some mollusks".

Following

members of molluscan and polychaete communities

Red bloom of algae is the best biological indicator for water pollution

I recommend Dr. Nagalakshmi Radhakrishnan for your answer.

Number of taxa i.e. snails indicate large quantities of Ca in water, water fleas clean the water. Appearance of blue-green algae indicate phosphorous rich water.