name a few pollutants that are biological in nature that is associated with such water?
human feces,  non-pathogenic bacteria and animals such as insects, arthropods and small fish.
Wastewater
If the wastewater contains human feces, as is the case for sewage, then it may also contain pathogens of one of the four types: 

It can also contain non-pathogenic bacteria and animals such as insects, arthropods and small fish.
does a leech bite? Yes are there bites venomous or poisonous? UNANSWERABLE what is its scientific name? Hirudinea from where does the name originate? UNANSWERABLE is there any correlation between leech and pollution? Exposure to synthetic estrogen from municipal wastewater, can affect leeches' reproductive systems what kind of cultural reference does it have in human society? Horse leech could drive elephants mad by climbing up inside their trunks to drink blood. any specific culture where such references are given? "Natural History" what are some reusable options for the water that affects the leech? It can be reused in industry, in artificial recharge of aquifers, in agriculture and in the rehabilitation of natural ecosystems.
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Wastewater [SEP] Biological pollutants
If the wastewater contains human feces, as is the case for sewage, then it may also contain pathogens of one of the four types: It can also contain non-pathogenic bacteria and animals such as insects, arthropods and small fish.